| Seq | Timestamp | Type | Name | Duration |
|---|---|---|---|---|
| 0/0 | 2026/08/10 12:21 | flow | patch-triage |
1mArgs:null Results: {
"EnableConfigs": [
"GUP_TEST"
],
"FocusSymbols": [
"gup_test_open",
"gup_test_release",
"gup_test_ioctl",
"pin_longterm_test_ioctl"
],
"KMSANReasoning": "The patch refactors the `pin_longterm_test` in `mm/gup_test.c` to use a per-file data structure (`struct gup_test_data`) instead of global variables, allowing concurrent users of the gup_test ioctl. The new structure is allocated using `kzalloc_obj`, which zero-initializes all fields. The array of page pointers is allocated using `kvcalloc`, which also zero-initializes the memory. The only data copied to user space is the content of the pinned user pages, which is identical to the pre-patch behavior and does not leak kernel memory. Any potential bugs introduced by these changes (e.g., use-after-free, double free, or memory leaks) would be effectively caught by KASAN and standard memory leak detectors. There is no risk of uninitialized memory usage or info-leaks that would require KMSAN.",
"NeedsKMSAN": false,
"Reasoning": "The patch modifies the gup_test debugfs interface to use per-file descriptor state instead of global state for the PIN_LONGTERM_TEST_* ioctls, fixing concurrency issues. This is a functional change to a test module that exposes kernel APIs to userspace, which is worth fuzzing to ensure the concurrency fix is correct and doesn't introduce new issues like memory leaks or use-after-free.",
"WorthFuzzing": true
} |
| 1/1 | 2026/08/10 12:21 | action | read-patch-diff |
0mArgs:null Results: {
"PatchDiff": "commit b6af6795da89164bb91f2ba9ba638ed4c3f7562a\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Mon Aug 10 12:21:49 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/mm/gup_test.c b/mm/gup_test.c\nindex eb4c9cda16ed8..44c1cdfb9c371 100644\n--- a/mm/gup_test.c\n+++ b/mm/gup_test.c\n@@ -8,6 +8,12 @@\n #include \u003clinux/highmem.h\u003e\n #include \"gup_test.h\"\n \n+struct gup_test_data {\n+\tstruct mutex longterm_mutex;\n+\tstruct page **longterm_pages;\n+\tunsigned long longterm_nr_pages;\n+};\n+\n static void put_back_pages(unsigned int cmd, struct page **pages,\n \t\t\t unsigned long nr_pages, unsigned int gup_test_flags)\n {\n@@ -208,23 +214,20 @@ static int __gup_test_ioctl(unsigned int cmd,\n \treturn ret;\n }\n \n-static DEFINE_MUTEX(pin_longterm_test_mutex);\n-static struct page **pin_longterm_test_pages;\n-static unsigned long pin_longterm_test_nr_pages;\n-\n-static inline void pin_longterm_test_stop(void)\n+static inline void pin_longterm_test_stop(struct gup_test_data *data)\n {\n-\tif (pin_longterm_test_pages) {\n-\t\tif (pin_longterm_test_nr_pages)\n-\t\t\tunpin_user_pages(pin_longterm_test_pages,\n-\t\t\t\t\t pin_longterm_test_nr_pages);\n-\t\tkvfree(pin_longterm_test_pages);\n-\t\tpin_longterm_test_pages = NULL;\n-\t\tpin_longterm_test_nr_pages = 0;\n+\tif (data-\u003elongterm_pages) {\n+\t\tif (data-\u003elongterm_nr_pages)\n+\t\t\tunpin_user_pages(data-\u003elongterm_pages,\n+\t\t\t\t\t data-\u003elongterm_nr_pages);\n+\t\tkvfree(data-\u003elongterm_pages);\n+\t\tdata-\u003elongterm_pages = NULL;\n+\t\tdata-\u003elongterm_nr_pages = 0;\n \t}\n }\n \n-static inline int pin_longterm_test_start(unsigned long arg)\n+static inline int pin_longterm_test_start(struct gup_test_data *data,\n+\t\tunsigned long arg)\n {\n \tlong nr_pages, cur_pages, addr, remaining_pages;\n \tint gup_flags = FOLL_LONGTERM;\n@@ -233,7 +236,7 @@ static inline int pin_longterm_test_start(unsigned long arg)\n \tint ret = 0;\n \tbool fast;\n \n-\tif (pin_longterm_test_pages)\n+\tif (data-\u003elongterm_pages)\n \t\treturn -EINVAL;\n \n \tif (copy_from_user(\u0026args, (void __user *)arg, sizeof(args)))\n@@ -263,12 +266,12 @@ static inline int pin_longterm_test_start(unsigned long arg)\n \t\treturn -EINTR;\n \t}\n \n-\tpin_longterm_test_pages = pages;\n-\tpin_longterm_test_nr_pages = 0;\n+\tdata-\u003elongterm_pages = pages;\n+\tdata-\u003elongterm_nr_pages = 0;\n \n-\twhile (nr_pages - pin_longterm_test_nr_pages) {\n-\t\tremaining_pages = nr_pages - pin_longterm_test_nr_pages;\n-\t\taddr = args.addr + pin_longterm_test_nr_pages * PAGE_SIZE;\n+\twhile (nr_pages - data-\u003elongterm_nr_pages) {\n+\t\tremaining_pages = nr_pages - data-\u003elongterm_nr_pages;\n+\t\taddr = args.addr + data-\u003elongterm_nr_pages * PAGE_SIZE;\n \n \t\tif (fast)\n \t\t\tcur_pages = pin_user_pages_fast(addr, remaining_pages,\n@@ -277,11 +280,11 @@ static inline int pin_longterm_test_start(unsigned long arg)\n \t\t\tcur_pages = pin_user_pages(addr, remaining_pages,\n \t\t\t\t\t\t gup_flags, pages);\n \t\tif (cur_pages \u003c 0) {\n-\t\t\tpin_longterm_test_stop();\n+\t\t\tpin_longterm_test_stop(data);\n \t\t\tret = cur_pages;\n \t\t\tbreak;\n \t\t}\n-\t\tpin_longterm_test_nr_pages += cur_pages;\n+\t\tdata-\u003elongterm_nr_pages += cur_pages;\n \t\tpages += cur_pages;\n \t}\n \n@@ -290,19 +293,20 @@ static inline int pin_longterm_test_start(unsigned long arg)\n \treturn ret;\n }\n \n-static inline int pin_longterm_test_read(unsigned long arg)\n+static inline int pin_longterm_test_read(struct gup_test_data *data,\n+\t\tunsigned long arg)\n {\n \t__u64 user_addr;\n \tunsigned long i;\n \n-\tif (!pin_longterm_test_pages)\n+\tif (!data-\u003elongterm_pages)\n \t\treturn -EINVAL;\n \n \tif (copy_from_user(\u0026user_addr, (void __user *)arg, sizeof(user_addr)))\n \t\treturn -EFAULT;\n \n-\tfor (i = 0; i \u003c pin_longterm_test_nr_pages; i++) {\n-\t\tvoid *addr = kmap_local_page(pin_longterm_test_pages[i]);\n+\tfor (i = 0; i \u003c data-\u003elongterm_nr_pages; i++) {\n+\t\tvoid *addr = kmap_local_page(data-\u003elongterm_pages[i]);\n \t\tunsigned long ret;\n \n \t\tret = copy_to_user((void __user *)(unsigned long)user_addr, addr,\n@@ -318,25 +322,26 @@ static inline int pin_longterm_test_read(unsigned long arg)\n static long pin_longterm_test_ioctl(struct file *filep, unsigned int cmd,\n \t\t\t\t unsigned long arg)\n {\n+\tstruct gup_test_data *data = filep-\u003eprivate_data;\n \tint ret = -EINVAL;\n \n-\tif (mutex_lock_killable(\u0026pin_longterm_test_mutex))\n+\tif (mutex_lock_killable(\u0026data-\u003elongterm_mutex))\n \t\treturn -EINTR;\n \n \tswitch (cmd) {\n \tcase PIN_LONGTERM_TEST_START:\n-\t\tret = pin_longterm_test_start(arg);\n+\t\tret = pin_longterm_test_start(data, arg);\n \t\tbreak;\n \tcase PIN_LONGTERM_TEST_STOP:\n-\t\tpin_longterm_test_stop();\n+\t\tpin_longterm_test_stop(data);\n \t\tret = 0;\n \t\tbreak;\n \tcase PIN_LONGTERM_TEST_READ:\n-\t\tret = pin_longterm_test_read(arg);\n+\t\tret = pin_longterm_test_read(data, arg);\n \t\tbreak;\n \t}\n \n-\tmutex_unlock(\u0026pin_longterm_test_mutex);\n+\tmutex_unlock(\u0026data-\u003elongterm_mutex);\n \treturn ret;\n }\n \n@@ -375,15 +380,40 @@ static long gup_test_ioctl(struct file *filep, unsigned int cmd,\n \treturn 0;\n }\n \n+static int gup_test_open(struct inode *inode, struct file *file)\n+{\n+\tstruct gup_test_data *data;\n+\tint ret;\n+\n+\tdata = kzalloc_obj(*data);\n+\tif (!data)\n+\t\treturn -ENOMEM;\n+\n+\tret = nonseekable_open(inode, file);\n+\tif (ret) {\n+\t\tkfree(data);\n+\t\treturn ret;\n+\t}\n+\n+\tmutex_init(\u0026data-\u003elongterm_mutex);\n+\tfile-\u003eprivate_data = data;\n+\treturn 0;\n+}\n+\n static int gup_test_release(struct inode *inode, struct file *file)\n {\n-\tpin_longterm_test_stop();\n+\tstruct gup_test_data *data = file-\u003eprivate_data;\n+\n+\tpin_longterm_test_stop(data);\n+\tmutex_destroy(\u0026data-\u003elongterm_mutex);\n+\tkfree(data);\n+\tfile-\u003eprivate_data = NULL;\n \n \treturn 0;\n }\n \n static const struct file_operations gup_test_fops = {\n-\t.open = nonseekable_open,\n+\t.open = gup_test_open,\n \t.unlocked_ioctl = gup_test_ioctl,\n \t.compat_ioctl = compat_ptr_ioctl,\n \t.release = gup_test_release,\n"
} |
| 2/1 | 2026/08/10 12:21 | agent | patch-evaluator |
0mModel:best-expensive Args: null Results: {
"EnableConfigs": [
"GUP_TEST"
],
"FocusSymbols": [
"gup_test_open",
"gup_test_release",
"gup_test_ioctl",
"pin_longterm_test_ioctl"
],
"Reasoning": "The patch modifies the gup_test debugfs interface to use per-file descriptor state instead of global state for the PIN_LONGTERM_TEST_* ioctls, fixing concurrency issues. This is a functional change to a test module that exposes kernel APIs to userspace, which is worth fuzzing to ensure the concurrency fix is correct and doesn't introduce new issues like memory leaks or use-after-free.",
"WorthFuzzing": true
}Instruction: You are an expert Linux kernel maintainer. Your job is to review a provided patch series and determine if it makes functional changes to the kernel that should be fuzzed. IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in your workspace. Do NOT rely on your internal knowledge of the kernel. You must actively use your code access tools to examine the actual source code and confirm any assumptions. Return WorthFuzzing=false if the patch only contains: - Modifications to Documentation/, Kconfig files, or code comments. - Purely decorative changes, such as logging (e.g., pr_err, printk) or tracepoints. - Changes to numeric constants or macros that do not functionally alter execution flow. - Code paths that are impossible to reach in virtualized environments like GCE or QEMU, even when utilizing software-emulated hardware (e.g., usb gadget, mac80211_hwsim). - Code in vendor-specific PCIe switch, SmartNIC, or GPU drivers (e.g., mlxsw, pds_core, qed, ionic, amdgpu) that require physical PCIe hardware cards not emulated in standard QEMU. - Driver .remove, .shutdown, or pci_unregister_driver teardown callbacks (e.g., igb_remove) that are executed only during PCI hot-unplug or sysfs driver unbind operations. If it modifies reachable core kernel logic, drivers, or architectures, use your code search tools to verify the code can be executed, then return WorthFuzzing=true. When returning WorthFuzzing=true, you MUST ALSO: 1. Extract any specific kernel functions that should be heavily fuzzed into FocusSymbols. Avoid listing generic hot-path functions to prevent skewed test distributions. Prefer non-static, non-inlined API entrypoint functions over internal static helper functions (which are inlined by the compiler and do not have distinct symbol addresses). 2. Identify any specific CONFIG_ options required to properly test this new/modified feature. Go and look into the Kconfig files and check for ifdefs around the code, do not make assumptions. Also check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed for Kbuild to compile the code statically into vmlinux. List them in the EnableConfigs output array, and DO NOT add a 'CONFIG_' prefix (e.g., return "NET_IPV4" instead of "CONFIG_NET_IPV4"). Prefer calling several tools at the same time to save round-trips. Use set-results tool to provide results of the analysis. It must be called exactly once before the final reply. Ignore results of this tool. Prompt: For your convenience, here is the diff of the changes:
commit b6af6795da89164bb91f2ba9ba638ed4c3f7562a
Author: syz-cluster <triage@syzkaller.com>
Date: Mon Aug 10 12:21:49 2026 +0000
syz-cluster: applied patch under review
diff --git a/mm/gup_test.c b/mm/gup_test.c
index eb4c9cda16ed8..44c1cdfb9c371 100644
--- a/mm/gup_test.c
+++ b/mm/gup_test.c
@@ -8,6 +8,12 @@
#include <linux/highmem.h>
#include "gup_test.h"
+struct gup_test_data {
+ struct mutex longterm_mutex;
+ struct page **longterm_pages;
+ unsigned long longterm_nr_pages;
+};
+
static void put_back_pages(unsigned int cmd, struct page **pages,
unsigned long nr_pages, unsigned int gup_test_flags)
{
@@ -208,23 +214,20 @@ static int __gup_test_ioctl(unsigned int cmd,
return ret;
}
-static DEFINE_MUTEX(pin_longterm_test_mutex);
-static struct page **pin_longterm_test_pages;
-static unsigned long pin_longterm_test_nr_pages;
-
-static inline void pin_longterm_test_stop(void)
+static inline void pin_longterm_test_stop(struct gup_test_data *data)
{
- if (pin_longterm_test_pages) {
- if (pin_longterm_test_nr_pages)
- unpin_user_pages(pin_longterm_test_pages,
- pin_longterm_test_nr_pages);
- kvfree(pin_longterm_test_pages);
- pin_longterm_test_pages = NULL;
- pin_longterm_test_nr_pages = 0;
+ if (data->longterm_pages) {
+ if (data->longterm_nr_pages)
+ unpin_user_pages(data->longterm_pages,
+ data->longterm_nr_pages);
+ kvfree(data->longterm_pages);
+ data->longterm_pages = NULL;
+ data->longterm_nr_pages = 0;
}
}
-static inline int pin_longterm_test_start(unsigned long arg)
+static inline int pin_longterm_test_start(struct gup_test_data *data,
+ unsigned long arg)
{
long nr_pages, cur_pages, addr, remaining_pages;
int gup_flags = FOLL_LONGTERM;
@@ -233,7 +236,7 @@ static inline int pin_longterm_test_start(unsigned long arg)
int ret = 0;
bool fast;
- if (pin_longterm_test_pages)
+ if (data->longterm_pages)
return -EINVAL;
if (copy_from_user(&args, (void __user *)arg, sizeof(args)))
@@ -263,12 +266,12 @@ static inline int pin_longterm_test_start(unsigned long arg)
return -EINTR;
}
- pin_longterm_test_pages = pages;
- pin_longterm_test_nr_pages = 0;
+ data->longterm_pages = pages;
+ data->longterm_nr_pages = 0;
- while (nr_pages - pin_longterm_test_nr_pages) {
- remaining_pages = nr_pages - pin_longterm_test_nr_pages;
- addr = args.addr + pin_longterm_test_nr_pages * PAGE_SIZE;
+ while (nr_pages - data->longterm_nr_pages) {
+ remaining_pages = nr_pages - data->longterm_nr_pages;
+ addr = args.addr + data->longterm_nr_pages * PAGE_SIZE;
if (fast)
cur_pages = pin_user_pages_fast(addr, remaining_pages,
@@ -277,11 +280,11 @@ static inline int pin_longterm_test_start(unsigned long arg)
cur_pages = pin_user_pages(addr, remaining_pages,
gup_flags, pages);
if (cur_pages < 0) {
- pin_longterm_test_stop();
+ pin_longterm_test_stop(data);
ret = cur_pages;
break;
}
- pin_longterm_test_nr_pages += cur_pages;
+ data->longterm_nr_pages += cur_pages;
pages += cur_pages;
}
@@ -290,19 +293,20 @@ static inline int pin_longterm_test_start(unsigned long arg)
return ret;
}
-static inline int pin_longterm_test_read(unsigned long arg)
+static inline int pin_longterm_test_read(struct gup_test_data *data,
+ unsigned long arg)
{
__u64 user_addr;
unsigned long i;
- if (!pin_longterm_test_pages)
+ if (!data->longterm_pages)
return -EINVAL;
if (copy_from_user(&user_addr, (void __user *)arg, sizeof(user_addr)))
return -EFAULT;
- for (i = 0; i < pin_longterm_test_nr_pages; i++) {
- void *addr = kmap_local_page(pin_longterm_test_pages[i]);
+ for (i = 0; i < data->longterm_nr_pages; i++) {
+ void *addr = kmap_local_page(data->longterm_pages[i]);
unsigned long ret;
ret = copy_to_user((void __user *)(unsigned long)user_addr, addr,
@@ -318,25 +322,26 @@ static inline int pin_longterm_test_read(unsigned long arg)
static long pin_longterm_test_ioctl(struct file *filep, unsigned int cmd,
unsigned long arg)
{
+ struct gup_test_data *data = filep->private_data;
int ret = -EINVAL;
- if (mutex_lock_killable(&pin_longterm_test_mutex))
+ if (mutex_lock_killable(&data->longterm_mutex))
return -EINTR;
switch (cmd) {
case PIN_LONGTERM_TEST_START:
- ret = pin_longterm_test_start(arg);
+ ret = pin_longterm_test_start(data, arg);
break;
case PIN_LONGTERM_TEST_STOP:
- pin_longterm_test_stop();
+ pin_longterm_test_stop(data);
ret = 0;
break;
case PIN_LONGTERM_TEST_READ:
- ret = pin_longterm_test_read(arg);
+ ret = pin_longterm_test_read(data, arg);
break;
}
- mutex_unlock(&pin_longterm_test_mutex);
+ mutex_unlock(&data->longterm_mutex);
return ret;
}
@@ -375,15 +380,40 @@ static long gup_test_ioctl(struct file *filep, unsigned int cmd,
return 0;
}
+static int gup_test_open(struct inode *inode, struct file *file)
+{
+ struct gup_test_data *data;
+ int ret;
+
+ data = kzalloc_obj(*data);
+ if (!data)
+ return -ENOMEM;
+
+ ret = nonseekable_open(inode, file);
+ if (ret) {
+ kfree(data);
+ return ret;
+ }
+
+ mutex_init(&data->longterm_mutex);
+ file->private_data = data;
+ return 0;
+}
+
static int gup_test_release(struct inode *inode, struct file *file)
{
- pin_longterm_test_stop();
+ struct gup_test_data *data = file->private_data;
+
+ pin_longterm_test_stop(data);
+ mutex_destroy(&data->longterm_mutex);
+ kfree(data);
+ file->private_data = NULL;
return 0;
}
static const struct file_operations gup_test_fops = {
- .open = nonseekable_open,
+ .open = gup_test_open,
.unlocked_ioctl = gup_test_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.release = gup_test_release,
|
| 3/2 | 2026/08/10 12:21 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 4026 output: 26 thoughts: 230 Thoughts: **Analyzing the GUP Test Module Patch** Okay, so this patch is touching `mm/gup_test.c`. The core of the change revolves around shifting some global state variables, `pin_longterm_test_mutex`, `pin_longterm_test_pages`, and `pin_longterm_test_nr_pages`, into a per-file descriptor structure, `struct gup_test_data`, which will now reside in `file->private_data`. This is a pretty straightforward refactoring to enable concurrent execution of the `PIN_LONGTERM_TEST_*` ioctls. Essentially, it removes the global locking bottleneck. Since this is a test module (`gup_test.c`), the immediate question is: is this reachable, and is it worth fuzzing? I mean, we usually don't prioritize fuzzing tests. But this module *does* expose kernel APIs like `pin_user_pages`, `unpin_user_pages`, etc., to userspace. That's a good target for fuzzing, actually, because those APIs can have interesting side-effects and might uncover some hidden memory management bugs. Wait a second… `gup_test` is a debugfs/test interface! That changes things. Let's pull up the kernel source in `mm/gup_test.c` and dig a little deeper. |
| 4/2 | 2026/08/10 12:21 | tool | grepper |
0mArgs:{
"Expression": "gup_test",
"PathPrefix": "mm/"
}Results: {
"Output": "mm/Kconfig=1293=config GUP_TEST\n--\nmm/Kconfig-1296-\thelp\nmm/Kconfig:1297:\t Provides /sys/kernel/debug/gup_test, which in turn provides a way\nmm/Kconfig-1298-\t to make ioctl calls that can launch kernel-based unit tests for\n--\nmm/Kconfig-1310-\nmm/Kconfig:1311:\t See tools/testing/selftests/mm/gup_test.c\nmm/Kconfig-1312-\n--\nmm/Makefile=109=obj-$(CONFIG_CGROUP_HUGETLB) += hugetlb_cgroup.o\nmm/Makefile:110:obj-$(CONFIG_GUP_TEST) += gup_test.o\nmm/Makefile-111-obj-$(CONFIG_DMAPOOL_TEST) += dmapool_test.o\n--\nmm/gup_test.c-8-#include \u003clinux/highmem.h\u003e\nmm/gup_test.c:9:#include \"gup_test.h\"\nmm/gup_test.c-10-\nmm/gup_test.c:11:struct gup_test_data {\nmm/gup_test.c-12-\tstruct mutex longterm_mutex;\n--\nmm/gup_test.c=17=static void put_back_pages(unsigned int cmd, struct page **pages,\nmm/gup_test.c:18:\t\t\t unsigned long nr_pages, unsigned int gup_test_flags)\nmm/gup_test.c-19-{\n--\nmm/gup_test.c-34-\tcase DUMP_USER_PAGES_TEST:\nmm/gup_test.c:35:\t\tif (gup_test_flags \u0026 GUP_TEST_FLAG_DUMP_PAGES_USE_PIN) {\nmm/gup_test.c-36-\t\t\tunpin_user_pages(pages, nr_pages);\n--\nmm/gup_test.c=46=static void verify_dma_pinned(unsigned int cmd, struct page **pages,\n--\nmm/gup_test.c-61-\nmm/gup_test.c:62:\t\t\t\tdump_page(\u0026folio-\u003epage, \"gup_test failure\");\nmm/gup_test.c-63-\t\t\t\tbreak;\n--\nmm/gup_test.c-67-\t\t\t\t i)) {\nmm/gup_test.c:68:\t\t\t\tdump_page(\u0026folio-\u003epage, \"gup_test failure\");\nmm/gup_test.c-69-\t\t\t\tbreak;\n--\nmm/gup_test.c-75-\nmm/gup_test.c:76:static void dump_pages_test(struct gup_test *gup, struct page **pages,\nmm/gup_test.c-77-\t\t\t unsigned long nr_pages)\n--\nmm/gup_test.c-101-\t\t\tdump_page(pages[index_to_dump],\nmm/gup_test.c:102:\t\t\t\t \"gup_test: dump_pages() test\");\nmm/gup_test.c-103-\t\t}\n--\nmm/gup_test.c-106-\nmm/gup_test.c:107:static int __gup_test_ioctl(unsigned int cmd,\nmm/gup_test.c:108:\t\tstruct gup_test *gup)\nmm/gup_test.c-109-{\n--\nmm/gup_test.c-216-\nmm/gup_test.c:217:static inline void pin_longterm_test_stop(struct gup_test_data *data)\nmm/gup_test.c-218-{\n--\nmm/gup_test.c-228-\nmm/gup_test.c:229:static inline int pin_longterm_test_start(struct gup_test_data *data,\nmm/gup_test.c-230-\t\tunsigned long arg)\n--\nmm/gup_test.c-295-\nmm/gup_test.c:296:static inline int pin_longterm_test_read(struct gup_test_data *data,\nmm/gup_test.c-297-\t\tunsigned long arg)\n--\nmm/gup_test.c=322=static long pin_longterm_test_ioctl(struct file *filep, unsigned int cmd,\n--\nmm/gup_test.c-324-{\nmm/gup_test.c:325:\tstruct gup_test_data *data = filep-\u003eprivate_data;\nmm/gup_test.c-326-\tint ret = -EINVAL;\n--\nmm/gup_test.c-347-\nmm/gup_test.c:348:static long gup_test_ioctl(struct file *filep, unsigned int cmd,\nmm/gup_test.c-349-\t\tunsigned long arg)\nmm/gup_test.c-350-{\nmm/gup_test.c:351:\tstruct gup_test gup;\nmm/gup_test.c-352-\tint ret;\n--\nmm/gup_test.c-372-\nmm/gup_test.c:373:\tret = __gup_test_ioctl(cmd, \u0026gup);\nmm/gup_test.c-374-\tif (ret)\n--\nmm/gup_test.c-382-\nmm/gup_test.c:383:static int gup_test_open(struct inode *inode, struct file *file)\nmm/gup_test.c-384-{\nmm/gup_test.c:385:\tstruct gup_test_data *data;\nmm/gup_test.c-386-\tint ret;\n--\nmm/gup_test.c-402-\nmm/gup_test.c:403:static int gup_test_release(struct inode *inode, struct file *file)\nmm/gup_test.c-404-{\nmm/gup_test.c:405:\tstruct gup_test_data *data = file-\u003eprivate_data;\nmm/gup_test.c-406-\n--\nmm/gup_test.c-414-\nmm/gup_test.c:415:static const struct file_operations gup_test_fops = {\nmm/gup_test.c:416:\t.open = gup_test_open,\nmm/gup_test.c:417:\t.unlocked_ioctl = gup_test_ioctl,\nmm/gup_test.c-418-\t.compat_ioctl = compat_ptr_ioctl,\nmm/gup_test.c:419:\t.release = gup_test_release,\nmm/gup_test.c-420-};\nmm/gup_test.c-421-\nmm/gup_test.c:422:static int __init gup_test_init(void)\nmm/gup_test.c-423-{\nmm/gup_test.c:424:\tdebugfs_create_file_unsafe(\"gup_test\", 0600, NULL, NULL,\nmm/gup_test.c:425:\t\t\t\t \u0026gup_test_fops);\nmm/gup_test.c-426-\n--\nmm/gup_test.c-429-\nmm/gup_test.c:430:late_initcall(gup_test_init);\n--\nmm/gup_test.h-6-\nmm/gup_test.h:7:#define GUP_FAST_BENCHMARK\t_IOWR('g', 1, struct gup_test)\nmm/gup_test.h:8:#define PIN_FAST_BENCHMARK\t_IOWR('g', 2, struct gup_test)\nmm/gup_test.h:9:#define PIN_LONGTERM_BENCHMARK\t_IOWR('g', 3, struct gup_test)\nmm/gup_test.h:10:#define GUP_BASIC_TEST\t\t_IOWR('g', 4, struct gup_test)\nmm/gup_test.h:11:#define PIN_BASIC_TEST\t\t_IOWR('g', 5, struct gup_test)\nmm/gup_test.h:12:#define DUMP_USER_PAGES_TEST\t_IOWR('g', 6, struct gup_test)\nmm/gup_test.h-13-#define PIN_LONGTERM_TEST_START\t_IOW('g', 7, struct pin_longterm_test)\n--\nmm/gup_test.h-20-\nmm/gup_test.h:21:struct gup_test {\nmm/gup_test.h-22-\t__u64 get_delta_usec;\n"
} |
| 5/2 | 2026/08/10 12:21 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 6864 output: 37 thoughts: 526 Thoughts: **Analyzing the gup_test.c Patch for Fuzzing Potential** Okay, so I'm looking at this patch in `mm/gup_test.c`. It's a debugfs interface, which is a big flag for me since that often means userspace interaction and potential fuzzing targets. Specifically, it's for testing `get_user_pages` and related functions – the `CONFIG_GUP_TEST` config is the key. The primary change here is fixing a concurrency issue within the `PIN_LONGTERM_TEST_*` ioctls. They've moved some global state into a per-file descriptor structure, `struct gup_test_data`. Functionally, this is a change within the test module itself. The first question that pops into my head is, "Is this fuzzable?" Since this exposes kernel APIs to userspace, it's a definite possibility, and probably a good idea. The listed modified functions are: `gup_test_open`, `gup_test_release`, `pin_longterm_test_start`, `pin_longterm_test_stop`, `pin_longterm_test_read`, `pin_longterm_test_ioctl`, and `gup_test_ioctl`. Wait, `gup_test_open` and `gup_test_release` are *new* functions introduced by this patch. And it looks like `pin_longterm_test_start`, `pin_longterm_test_stop`, and `pin_longterm_test_read` are *modified*. These are all static functions which is important. However, `gup_test_open`, `gup_test_release`, and `gup_test_ioctl` are exposed via `file_operations` which is different. The prompt says that we prefer non-static, non-inlined API entrypoint functions over internal static helper functions. Hang on… looking closer, `pin_longterm_test_start` *is* inline. So, that's not a clear fuzzing target, but the `gup_test_open`, and `gup_test_release`, and `gup_test_ioctl` are *not* inline. These are actually passed as function pointers in the `file_operations` struct. This means they cannot be inlined, and will have distinct symbol addresses. So, we're definitely looking at potential fuzzing surface here. I need to confirm if `gup_test_open` is static. Yes, it's static, but this is less important, it's passed as a function pointer. This means the compiler won't inline it. Same with `gup_test_release`, it is also static but is passed as function pointer. Then there's `gup_test_ioctl` as well! And `pin_longterm_test_ioctl` is called from `gup_test_ioctl`. This warrants a closer look at the actual code for `gup_test_ioctl` in `mm/gup_test.c`. |
| 6/2 | 2026/08/10 12:22 | tool | read-file |
0mArgs:{
"File": "mm/gup_test.c",
"FirstLine": 320,
"LineCount": 100
}Results: {
"Contents": " 320:\t}\n 321:\t\n 322:\tstatic long pin_longterm_test_ioctl(struct file *filep, unsigned int cmd,\n 323:\t\t\t\t\t unsigned long arg)\n 324:\t{\n 325:\t\tstruct gup_test_data *data = filep-\u003eprivate_data;\n 326:\t\tint ret = -EINVAL;\n 327:\t\n 328:\t\tif (mutex_lock_killable(\u0026data-\u003elongterm_mutex))\n 329:\t\t\treturn -EINTR;\n 330:\t\n 331:\t\tswitch (cmd) {\n 332:\t\tcase PIN_LONGTERM_TEST_START:\n 333:\t\t\tret = pin_longterm_test_start(data, arg);\n 334:\t\t\tbreak;\n 335:\t\tcase PIN_LONGTERM_TEST_STOP:\n 336:\t\t\tpin_longterm_test_stop(data);\n 337:\t\t\tret = 0;\n 338:\t\t\tbreak;\n 339:\t\tcase PIN_LONGTERM_TEST_READ:\n 340:\t\t\tret = pin_longterm_test_read(data, arg);\n 341:\t\t\tbreak;\n 342:\t\t}\n 343:\t\n 344:\t\tmutex_unlock(\u0026data-\u003elongterm_mutex);\n 345:\t\treturn ret;\n 346:\t}\n 347:\t\n 348:\tstatic long gup_test_ioctl(struct file *filep, unsigned int cmd,\n 349:\t\t\tunsigned long arg)\n 350:\t{\n 351:\t\tstruct gup_test gup;\n 352:\t\tint ret;\n 353:\t\n 354:\t\tswitch (cmd) {\n 355:\t\tcase GUP_FAST_BENCHMARK:\n 356:\t\tcase PIN_FAST_BENCHMARK:\n 357:\t\tcase PIN_LONGTERM_BENCHMARK:\n 358:\t\tcase GUP_BASIC_TEST:\n 359:\t\tcase PIN_BASIC_TEST:\n 360:\t\tcase DUMP_USER_PAGES_TEST:\n 361:\t\t\tbreak;\n 362:\t\tcase PIN_LONGTERM_TEST_START:\n 363:\t\tcase PIN_LONGTERM_TEST_STOP:\n 364:\t\tcase PIN_LONGTERM_TEST_READ:\n 365:\t\t\treturn pin_longterm_test_ioctl(filep, cmd, arg);\n 366:\t\tdefault:\n 367:\t\t\treturn -EINVAL;\n 368:\t\t}\n 369:\t\n 370:\t\tif (copy_from_user(\u0026gup, (void __user *)arg, sizeof(gup)))\n 371:\t\t\treturn -EFAULT;\n 372:\t\n 373:\t\tret = __gup_test_ioctl(cmd, \u0026gup);\n 374:\t\tif (ret)\n 375:\t\t\treturn ret;\n 376:\t\n 377:\t\tif (copy_to_user((void __user *)arg, \u0026gup, sizeof(gup)))\n 378:\t\t\treturn -EFAULT;\n 379:\t\n 380:\t\treturn 0;\n 381:\t}\n 382:\t\n 383:\tstatic int gup_test_open(struct inode *inode, struct file *file)\n 384:\t{\n 385:\t\tstruct gup_test_data *data;\n 386:\t\tint ret;\n 387:\t\n 388:\t\tdata = kzalloc_obj(*data);\n 389:\t\tif (!data)\n 390:\t\t\treturn -ENOMEM;\n 391:\t\n 392:\t\tret = nonseekable_open(inode, file);\n 393:\t\tif (ret) {\n 394:\t\t\tkfree(data);\n 395:\t\t\treturn ret;\n 396:\t\t}\n 397:\t\n 398:\t\tmutex_init(\u0026data-\u003elongterm_mutex);\n 399:\t\tfile-\u003eprivate_data = data;\n 400:\t\treturn 0;\n 401:\t}\n 402:\t\n 403:\tstatic int gup_test_release(struct inode *inode, struct file *file)\n 404:\t{\n 405:\t\tstruct gup_test_data *data = file-\u003eprivate_data;\n 406:\t\n 407:\t\tpin_longterm_test_stop(data);\n 408:\t\tmutex_destroy(\u0026data-\u003elongterm_mutex);\n 409:\t\tkfree(data);\n 410:\t\tfile-\u003eprivate_data = NULL;\n 411:\t\n 412:\t\treturn 0;\n 413:\t}\n 414:\t\n 415:\tstatic const struct file_operations gup_test_fops = {\n 416:\t\t.open = gup_test_open,\n 417:\t\t.unlocked_ioctl = gup_test_ioctl,\n 418:\t\t.compat_ioctl = compat_ptr_ioctl,\n 419:\t\t.release = gup_test_release,\n"
} |
| 7/2 | 2026/08/10 12:22 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 9449 output: 33 thoughts: 76 Thoughts: **Analyzing Recent Code Changes** Okay, so I'm looking at these recent modifications, specifically the addition or alterations of the functions `gup_test_open`, `gup_test_release`, `gup_test_ioctl`, and `pin_longterm_test_ioctl`. They aren't inlined, which is something I need to keep in mind. The overall config being used is `GUP_TEST`. Given the nature of these functions, which deal with IOCTLs and resource management, my immediate thought is to check the `mm/Kconfig` file. I need to understand the dependencies associated with `GUP_TEST`. This will give me a better understanding of what other features or configurations might be involved and what the purpose of `GUP_TEST` actually is. Time to dig into the Kconfig! |
| 8/2 | 2026/08/10 12:22 | tool | read-file |
0mArgs:{
"File": "mm/Kconfig",
"FirstLine": 1290,
"LineCount": 30
}Results: {
"Contents": "1290:\t\t information includes global and per chunk statistics, which can\n1291:\t\t be used to help understand percpu memory usage.\n1292:\t\n1293:\tconfig GUP_TEST\n1294:\t\tbool \"Enable infrastructure for get_user_pages()-related unit tests\"\n1295:\t\tdepends on DEBUG_FS\n1296:\t\thelp\n1297:\t\t Provides /sys/kernel/debug/gup_test, which in turn provides a way\n1298:\t\t to make ioctl calls that can launch kernel-based unit tests for\n1299:\t\t the get_user_pages*() and pin_user_pages*() family of API calls.\n1300:\t\n1301:\t\t These tests include benchmark testing of the _fast variants of\n1302:\t\t get_user_pages*() and pin_user_pages*(), as well as smoke tests of\n1303:\t\t the non-_fast variants.\n1304:\t\n1305:\t\t There is also a sub-test that allows running dump_page() on any\n1306:\t\t of up to eight pages (selected by command line args) within the\n1307:\t\t range of user-space addresses. These pages are either pinned via\n1308:\t\t pin_user_pages*(), or pinned via get_user_pages*(), as specified\n1309:\t\t by other command line arguments.\n1310:\t\n1311:\t\t See tools/testing/selftests/mm/gup_test.c\n1312:\t\n1313:\tcomment \"GUP_TEST needs to have DEBUG_FS enabled\"\n1314:\t\tdepends on !GUP_TEST \u0026\u0026 !DEBUG_FS\n1315:\t\n1316:\tconfig GUP_GET_PXX_LOW_HIGH\n1317:\t\tbool\n1318:\t\n1319:\tconfig DMAPOOL_TEST\n"
} |
| 9/2 | 2026/08/10 12:22 | llm | patch-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 10239 output: 159 thoughts: 514 Thoughts: **Fuzzing Strategy for `gup_test` Module** Okay, so I'm looking at this patch and I've got a plan for fuzzing it. The key here is the `gup_test` debugfs interface. The dependencies are clear - `DEBUG_FS`, and since `GUP_TEST` enables the functionality, that's what I'll need to enable in the configuration. My first thought is, is this even *worth* fuzzing? Absolutely! It's a test module, yes, but it exposes kernel APIs to userspace. This patch specifically addresses a concurrency issue, and concurrency bugs are precisely what fuzzers excel at uncovering and validating fixes for. This is a classic opportunity. The functions that are most likely to be interesting are `gup_test_open`, `gup_test_release`, `gup_test_ioctl`, and `pin_longterm_test_ioctl`. I initially had a concern about `pin_longterm_test_start`, `pin_longterm_test_stop`, and `pin_longterm_test_read` since they are inline and won't have their own distinct symbol addresses. Since this is an ioctl based interface, it makes sense to focus on the `*_ioctl` functions. Let's do a quick check on the `pin_longterm_test_ioctl` function since it could be inlined. Ah, yes, it's `static long pin_longterm_test_ioctl(...)`. It's called from `gup_test_ioctl`, which is also `static long gup_test_ioctl(...)`. Since it's only called from one place, the compiler *might* inline it. However, `gup_test_ioctl` is not inlined because it's passed as a function pointer. Therefore, `gup_test_ioctl` is definitely a good target. Likewise, `gup_test_open` and `gup_test_release` are passed as function pointers too. So, to summarize, I'm listing: * `gup_test_open` * `gup_test_release` * `gup_test_ioctl` * `pin_longterm_test_ioctl` The config needed for this is `GUP_TEST`. Essentially, the patch alters the `gup_test` debugfs interface to use per-file descriptor state for the `PIN_LONGTERM_TEST_*` ioctls, fixing concurrency problems. This is a functional change to a test module that exposes kernel APIs to userspace. It is worth fuzzing to ensure the concurrency fix is correct and doesn't introduce any new issues such as memory leaks or use-after-free conditions. Now, let's call set-results. |
| 10/2 | 2026/08/10 12:22 | tool | set-results |
0mArgs:{
"EnableConfigs": [
"GUP_TEST"
],
"FocusSymbols": [
"gup_test_open",
"gup_test_release",
"gup_test_ioctl",
"pin_longterm_test_ioctl"
],
"Reasoning": "The patch modifies the gup_test debugfs interface to use per-file descriptor state instead of global state for the PIN_LONGTERM_TEST_* ioctls, fixing concurrency issues. This is a functional change to a test module that exposes kernel APIs to userspace, which is worth fuzzing to ensure the concurrency fix is correct and doesn't introduce new issues like memory leaks or use-after-free.",
"WorthFuzzing": true
}Results: {
"EnableConfigs": [
"GUP_TEST"
],
"FocusSymbols": [
"gup_test_open",
"gup_test_release",
"gup_test_ioctl",
"pin_longterm_test_ioctl"
],
"Reasoning": "The patch modifies the gup_test debugfs interface to use per-file descriptor state instead of global state for the PIN_LONGTERM_TEST_* ioctls, fixing concurrency issues. This is a functional change to a test module that exposes kernel APIs to userspace, which is worth fuzzing to ensure the concurrency fix is correct and doesn't introduce new issues like memory leaks or use-after-free.",
"WorthFuzzing": true
} |
| 11/1 | 2026/08/10 12:22 | action | If |
0mArgs:{
"WorthFuzzing": true
}Results: null |
| 12/2 | 2026/08/10 12:22 | agent | kmsan-evaluator |
0mModel:best-expensive Args: null Results: {
"KMSANReasoning": "The patch refactors the `pin_longterm_test` in `mm/gup_test.c` to use a per-file data structure (`struct gup_test_data`) instead of global variables, allowing concurrent users of the gup_test ioctl. The new structure is allocated using `kzalloc_obj`, which zero-initializes all fields. The array of page pointers is allocated using `kvcalloc`, which also zero-initializes the memory. The only data copied to user space is the content of the pinned user pages, which is identical to the pre-patch behavior and does not leak kernel memory. Any potential bugs introduced by these changes (e.g., use-after-free, double free, or memory leaks) would be effectively caught by KASAN and standard memory leak detectors. There is no risk of uninitialized memory usage or info-leaks that would require KMSAN.",
"NeedsKMSAN": false
}Instruction: You are an expert Linux kernel security engineer specializing in kernel memory
error detectors (KASAN and KMSAN). Your job is to review the provided patch series and
determine if the code changes justify spawning a dedicated KMSAN (KernelMemorySanitizer)
fuzzing session in addition to standard KASAN fuzzing.
CRITICAL DISTINCTION BETWEEN KASAN AND KMSAN:
- Standard KASAN kernel builds (upstream-apparmor-kasan.config) already enable
a comprehensive suite of debugging tools and sanitizers, including KASAN
(out-of-bounds accesses, use-after-free, double free, invalid free), LOCKDEP
(locking bugs and deadlocks), UB-sanitizers, and memory corruption checks.
- KMSAN (KernelMemorySanitizer) detects reads of UNINITIALIZED memory (stack, heap,
or page allocations) and kernel-to-user memory info-leaks.
Rule: THERE IS NO SENSE IN RUNNING A KMSAN SESSION IF A BUG CAN BE CAUGHT BY KASAN,
LOCKDEP, OR OTHER STANDARD BUG DETECTORS.
A dedicated KMSAN fuzzing session incurs significant resource costs. You must ONLY
set NeedsKMSAN=true if the code changes introduce or expose UNINITIALIZED MEMORY risks
that are detected ONLY by KMSAN.
Look holistically at the patch series and surrounding code. Even if no direct
uninitialized field accesses or new buffer allocations are added in the diff itself,
a patch may alter control flow, bounds checking, or data length calculations in ways
that change how the rest of the code operates on existing buffers (e.g. allowing
uninitialized stack/heap memory to be read, copied to user space, or used in control
flow). Do not hesitate to use your code access tools to inspect the surrounding code,
called functions, and callers.
Set NeedsKMSAN=true ONLY IF the patch introduces or modifies:
1. Kernel structures sent to user space (via copy_to_user, put_user, netlink skb
attributes, ioctl output arguments, socket options, or BPF buffers) where fields
or structure padding might not be fully initialized/zeroed.
2. Conditional logic or branching that depends on potentially uninitialized variables
or struct fields.
3. Allocation or initialization of complex data structures where uninitialized fields
could be read later in reachable code paths.
4. Bounds checks, lengths, or logic in a way that allows surrounding code to access
uninitialized bytes of existing buffers.
Set NeedsKMSAN=false IF:
- The code changes primarily risk out-of-bounds access, array overflows, NULL pointer
dereferences, locking deadlocks, or use-after-free bugs (these are already caught
by KASAN, LOCKDEP, or standard bug detectors).
- All stack/heap structures touched or introduced by the patch are fully zeroed
or initialized (e.g. using = {0}, memset, kzalloc) before being read or copied.
- The patch does not introduce any risk of uninitialized memory usage or info-leaks.
Use your code access tools to inspect the surrounding code if necessary, then provide
detailed KMSANReasoning contrasting KASAN vs KMSAN applicability for this patch.
Prefer calling several tools at the same time to save round-trips.
Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.
Prompt: For your convenience, here is the diff of the changes:
commit b6af6795da89164bb91f2ba9ba638ed4c3f7562a
Author: syz-cluster <triage@syzkaller.com>
Date: Mon Aug 10 12:21:49 2026 +0000
syz-cluster: applied patch under review
diff --git a/mm/gup_test.c b/mm/gup_test.c
index eb4c9cda16ed8..44c1cdfb9c371 100644
--- a/mm/gup_test.c
+++ b/mm/gup_test.c
@@ -8,6 +8,12 @@
#include <linux/highmem.h>
#include "gup_test.h"
+struct gup_test_data {
+ struct mutex longterm_mutex;
+ struct page **longterm_pages;
+ unsigned long longterm_nr_pages;
+};
+
static void put_back_pages(unsigned int cmd, struct page **pages,
unsigned long nr_pages, unsigned int gup_test_flags)
{
@@ -208,23 +214,20 @@ static int __gup_test_ioctl(unsigned int cmd,
return ret;
}
-static DEFINE_MUTEX(pin_longterm_test_mutex);
-static struct page **pin_longterm_test_pages;
-static unsigned long pin_longterm_test_nr_pages;
-
-static inline void pin_longterm_test_stop(void)
+static inline void pin_longterm_test_stop(struct gup_test_data *data)
{
- if (pin_longterm_test_pages) {
- if (pin_longterm_test_nr_pages)
- unpin_user_pages(pin_longterm_test_pages,
- pin_longterm_test_nr_pages);
- kvfree(pin_longterm_test_pages);
- pin_longterm_test_pages = NULL;
- pin_longterm_test_nr_pages = 0;
+ if (data->longterm_pages) {
+ if (data->longterm_nr_pages)
+ unpin_user_pages(data->longterm_pages,
+ data->longterm_nr_pages);
+ kvfree(data->longterm_pages);
+ data->longterm_pages = NULL;
+ data->longterm_nr_pages = 0;
}
}
-static inline int pin_longterm_test_start(unsigned long arg)
+static inline int pin_longterm_test_start(struct gup_test_data *data,
+ unsigned long arg)
{
long nr_pages, cur_pages, addr, remaining_pages;
int gup_flags = FOLL_LONGTERM;
@@ -233,7 +236,7 @@ static inline int pin_longterm_test_start(unsigned long arg)
int ret = 0;
bool fast;
- if (pin_longterm_test_pages)
+ if (data->longterm_pages)
return -EINVAL;
if (copy_from_user(&args, (void __user *)arg, sizeof(args)))
@@ -263,12 +266,12 @@ static inline int pin_longterm_test_start(unsigned long arg)
return -EINTR;
}
- pin_longterm_test_pages = pages;
- pin_longterm_test_nr_pages = 0;
+ data->longterm_pages = pages;
+ data->longterm_nr_pages = 0;
- while (nr_pages - pin_longterm_test_nr_pages) {
- remaining_pages = nr_pages - pin_longterm_test_nr_pages;
- addr = args.addr + pin_longterm_test_nr_pages * PAGE_SIZE;
+ while (nr_pages - data->longterm_nr_pages) {
+ remaining_pages = nr_pages - data->longterm_nr_pages;
+ addr = args.addr + data->longterm_nr_pages * PAGE_SIZE;
if (fast)
cur_pages = pin_user_pages_fast(addr, remaining_pages,
@@ -277,11 +280,11 @@ static inline int pin_longterm_test_start(unsigned long arg)
cur_pages = pin_user_pages(addr, remaining_pages,
gup_flags, pages);
if (cur_pages < 0) {
- pin_longterm_test_stop();
+ pin_longterm_test_stop(data);
ret = cur_pages;
break;
}
- pin_longterm_test_nr_pages += cur_pages;
+ data->longterm_nr_pages += cur_pages;
pages += cur_pages;
}
@@ -290,19 +293,20 @@ static inline int pin_longterm_test_start(unsigned long arg)
return ret;
}
-static inline int pin_longterm_test_read(unsigned long arg)
+static inline int pin_longterm_test_read(struct gup_test_data *data,
+ unsigned long arg)
{
__u64 user_addr;
unsigned long i;
- if (!pin_longterm_test_pages)
+ if (!data->longterm_pages)
return -EINVAL;
if (copy_from_user(&user_addr, (void __user *)arg, sizeof(user_addr)))
return -EFAULT;
- for (i = 0; i < pin_longterm_test_nr_pages; i++) {
- void *addr = kmap_local_page(pin_longterm_test_pages[i]);
+ for (i = 0; i < data->longterm_nr_pages; i++) {
+ void *addr = kmap_local_page(data->longterm_pages[i]);
unsigned long ret;
ret = copy_to_user((void __user *)(unsigned long)user_addr, addr,
@@ -318,25 +322,26 @@ static inline int pin_longterm_test_read(unsigned long arg)
static long pin_longterm_test_ioctl(struct file *filep, unsigned int cmd,
unsigned long arg)
{
+ struct gup_test_data *data = filep->private_data;
int ret = -EINVAL;
- if (mutex_lock_killable(&pin_longterm_test_mutex))
+ if (mutex_lock_killable(&data->longterm_mutex))
return -EINTR;
switch (cmd) {
case PIN_LONGTERM_TEST_START:
- ret = pin_longterm_test_start(arg);
+ ret = pin_longterm_test_start(data, arg);
break;
case PIN_LONGTERM_TEST_STOP:
- pin_longterm_test_stop();
+ pin_longterm_test_stop(data);
ret = 0;
break;
case PIN_LONGTERM_TEST_READ:
- ret = pin_longterm_test_read(arg);
+ ret = pin_longterm_test_read(data, arg);
break;
}
- mutex_unlock(&pin_longterm_test_mutex);
+ mutex_unlock(&data->longterm_mutex);
return ret;
}
@@ -375,15 +380,40 @@ static long gup_test_ioctl(struct file *filep, unsigned int cmd,
return 0;
}
+static int gup_test_open(struct inode *inode, struct file *file)
+{
+ struct gup_test_data *data;
+ int ret;
+
+ data = kzalloc_obj(*data);
+ if (!data)
+ return -ENOMEM;
+
+ ret = nonseekable_open(inode, file);
+ if (ret) {
+ kfree(data);
+ return ret;
+ }
+
+ mutex_init(&data->longterm_mutex);
+ file->private_data = data;
+ return 0;
+}
+
static int gup_test_release(struct inode *inode, struct file *file)
{
- pin_longterm_test_stop();
+ struct gup_test_data *data = file->private_data;
+
+ pin_longterm_test_stop(data);
+ mutex_destroy(&data->longterm_mutex);
+ kfree(data);
+ file->private_data = NULL;
return 0;
}
static const struct file_operations gup_test_fops = {
- .open = nonseekable_open,
+ .open = gup_test_open,
.unlocked_ioctl = gup_test_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.release = gup_test_release,
|
| 13/3 | 2026/08/10 12:22 | llm | kmsan-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 4023 output: 18 thoughts: 276 Thoughts: **Refactoring `mm/gup_test.c` for Concurrent GUP Test Usage** Okay, so this patch is aimed at improving the concurrency of the `gup_test` ioctl. Currently, the code, specifically the `pin_longterm_test` functionality, relies on global variables. That's a classic bottleneck, especially if we want to allow multiple users to run `gup_test` concurrently. So, the refactor is a good move. My initial thought is to check how they’re doing it. The key is using a per-file data structure, `struct gup_test_data`, to replace those global variables: `pin_longterm_test_mutex`, `pin_longterm_test_pages`, and `pin_longterm_test_nr_pages`. That's the right approach; per-file locking and data is the obvious solution here. Now, let's dive into the specifics of the changes. First, they define the structure, `struct gup_test_data`. Fine, understandable. Okay, now let's see how this structure is instantiated. Ah, in `gup_test_open`, it looks like `data` is allocated using `kzalloc_obj(*data)`. Wait, `kzalloc_obj`? That's not a standard kernel function, is it? It's unfamiliar. I need to make sure this isn't a typo or some custom macro within this patch or the larger project. It seems odd, as the usual kernel allocation function is `kzalloc`. Unless this is a recent addition. Okay, let's assume it's `kzalloc(sizeof(*data), GFP_KERNEL)` for now, but I need to check. It's best practice to confirm the details. Let's see if it's a macro defined somewhere, or perhaps a typo. Grepping for `kzalloc_obj` is the next logical step. |
| 14/3 | 2026/08/10 12:22 | tool | grepper |
0mArgs:{
"Expression": "kzalloc_obj"
}Results: {
"Output": "\nFull output is too long, showing 500 out of 79138 lines.\nUse more precise expression if possible.\n\nDocumentation/core-api/list.rst=103=list:\n--\nDocumentation/core-api/list.rst-114-\nDocumentation/core-api/list.rst:115: grock = kzalloc_obj(*grock);\nDocumentation/core-api/list.rst-116- if (!grock)\n--\nDocumentation/core-api/list.rst-125-\nDocumentation/core-api/list.rst:126: dimitri = kzalloc_obj(*dimitri);\nDocumentation/core-api/list.rst-127- if (!dimitri)\n--\nDocumentation/driver-api/mailbox.rst=45=a message and a callback function to the API and return immediately).\n--\nDocumentation/driver-api/mailbox.rst-89-\nDocumentation/driver-api/mailbox.rst:90:\t\tdc_sync = kzalloc_obj(*dc_sync);\nDocumentation/driver-api/mailbox.rst:91:\t\tdc_async = kzalloc_obj(*dc_async);\nDocumentation/driver-api/mailbox.rst-92-\n--\nDocumentation/driver-api/media/v4l2-fh.rst=26=Example:\n--\nDocumentation/driver-api/media/v4l2-fh.rst-44-\nDocumentation/driver-api/media/v4l2-fh.rst:45:\t\tmy_fh = kzalloc_obj(*my_fh);\nDocumentation/driver-api/media/v4l2-fh.rst-46-\n--\nDocumentation/process/coding-style.rst=938=The kernel provides the following general purpose memory allocators:\nDocumentation/process/coding-style.rst:939:kmalloc(), kzalloc(), kmalloc_objs(), kzalloc_objs(), vmalloc(), and\nDocumentation/process/coding-style.rst-940-vzalloc(). Please refer to the API documentation for further information\n--\nDocumentation/process/coding-style.rst=964=The preferred form for allocating a zeroed array is the following:\n--\nDocumentation/process/coding-style.rst-967-\nDocumentation/process/coding-style.rst:968:\tp = kzalloc_objs(*p, n, ...);\nDocumentation/process/coding-style.rst-969-\n--\nDocumentation/process/deprecated.rst=398=become, respectively::\n--\nDocumentation/process/deprecated.rst-400-\tptr = kmalloc_obj(*ptr [, gfp] );\nDocumentation/process/deprecated.rst:401:\tptr = kzalloc_obj(*ptr [, gfp] );\nDocumentation/process/deprecated.rst-402-\tptr = kmalloc_objs(*ptr, count [, gfp] );\nDocumentation/process/deprecated.rst:403:\tptr = kzalloc_objs(*ptr, count [, gfp] );\nDocumentation/process/deprecated.rst-404-\tptr = kmalloc_flex(*ptr, flex_member, count [, gfp] );\n--\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst=208=to details explained in the following section.\n--\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst-268- /* allocate a chip-specific data with zero filled */\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst:269: chip = kzalloc_obj(*chip);\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst-270- if (chip == NULL)\n--\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst=623=After allocating a card instance via :c:func:`snd_card_new()`\n--\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst-630- .....\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst:631: chip = kzalloc_obj(*chip);\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst-632-\n--\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst=698=destructor and PCI entries. Example code is shown first, below::\n--\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst-749-\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst:750: chip = kzalloc_obj(*chip);\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst-751- if (chip == NULL) {\n--\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst=3823=chip data individually::\n--\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst-3835- ....\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst:3836: chip = kzalloc_obj(*chip);\nDocumentation/sound/kernel-api/writing-an-alsa-driver.rst-3837- ....\n--\nDocumentation/translations/zh_CN/video4linux/v4l2-framework.txt=794=int my_open(struct file *file)\n--\nDocumentation/translations/zh_CN/video4linux/v4l2-framework.txt-801-\nDocumentation/translations/zh_CN/video4linux/v4l2-framework.txt:802:\tmy_fh = kzalloc_obj(*my_fh);\nDocumentation/translations/zh_CN/video4linux/v4l2-framework.txt-803-\n--\narch/alpha/kernel/module.c=64=module_frob_arch_sections(Elf64_Ehdr *hdr, Elf64_Shdr *sechdrs,\n--\narch/alpha/kernel/module.c-95-\tnsyms = symtab-\u003esh_size / sizeof(Elf64_Sym);\narch/alpha/kernel/module.c:96:\tchains = kzalloc_objs(struct got_entry, nsyms);\narch/alpha/kernel/module.c-97-\tif (!chains) {\n--\narch/alpha/kernel/setup.c=390=register_cpus(void)\n--\narch/alpha/kernel/setup.c-394-\tfor_each_possible_cpu(i) {\narch/alpha/kernel/setup.c:395:\t\tstruct cpu *p = kzalloc_obj(*p);\narch/alpha/kernel/setup.c-396-\t\tif (!p)\n--\narch/arc/net/bpf_jit_core.c=1120=static int jit_prepare_final_mem_alloc(struct jit_context *ctx)\n--\narch/arc/net/bpf_jit_core.c-1131-\tif (ctx-\u003eneed_extra_pass) {\narch/arc/net/bpf_jit_core.c:1132:\t\tctx-\u003ejit_data = kzalloc_obj(*ctx-\u003ejit_data);\narch/arc/net/bpf_jit_core.c-1133-\t\tif (!ctx-\u003ejit_data)\n--\narch/arm/common/locomo.c=220=locomo_init_one_child(struct locomo *lchip, struct locomo_dev_info *info)\n--\narch/arm/common/locomo.c-224-\narch/arm/common/locomo.c:225:\tdev = kzalloc_obj(struct locomo_dev);\narch/arm/common/locomo.c-226-\tif (!dev) {\n--\narch/arm/common/locomo.c=356=__locomo_probe(struct device *me, struct resource *mem, int irq)\n--\narch/arm/common/locomo.c-362-\narch/arm/common/locomo.c:363:\tlchip = kzalloc_obj(struct locomo);\narch/arm/common/locomo.c-364-\tif (!lchip)\n--\narch/arm/common/sa1111.c=733=sa1111_init_one_child(struct sa1111 *sachip, struct resource *parent,\n--\narch/arm/common/sa1111.c-739-\narch/arm/common/sa1111.c:740:\tdev = kzalloc_obj(struct sa1111_dev);\narch/arm/common/sa1111.c-741-\tif (!dev) {\n--\narch/arm/common/scoop.c=178=static int scoop_probe(struct platform_device *pdev)\n--\narch/arm/common/scoop.c-187-\narch/arm/common/scoop.c:188:\tdevptr = kzalloc_obj(struct scoop_dev);\narch/arm/common/scoop.c-189-\tif (!devptr)\n--\narch/arm/kernel/smp.c=108=static int secondary_biglittle_prepare(unsigned int cpu)\n--\narch/arm/kernel/smp.c-110-\tif (!cpu_vtable[cpu])\narch/arm/kernel/smp.c:111:\t\tcpu_vtable[cpu] = kzalloc_obj(*cpu_vtable[cpu]);\narch/arm/kernel/smp.c-112-\n--\narch/arm/kernel/vdso.c=169=static int __init vdso_init(void)\n--\narch/arm/kernel/vdso.c-181-\t/* Allocate the VDSO text pagelist */\narch/arm/kernel/vdso.c:182:\tvdso_text_pagelist = kzalloc_objs(struct page *, text_pages);\narch/arm/kernel/vdso.c-183-\tif (vdso_text_pagelist == NULL)\n--\narch/arm/mach-footbridge/dc21285.c=261=int __init dc21285_setup(int nr, struct pci_sys_data *sys)\n--\narch/arm/mach-footbridge/dc21285.c-264-\narch/arm/mach-footbridge/dc21285.c:265:\tres = kzalloc_objs(struct resource, 2);\narch/arm/mach-footbridge/dc21285.c-266-\tif (!res) {\n--\narch/arm/mach-footbridge/ebsa285.c=69=static int __init ebsa285_leds_init(void)\n--\narch/arm/mach-footbridge/ebsa285.c-86-\narch/arm/mach-footbridge/ebsa285.c:87:\t\tled = kzalloc_obj(*led);\narch/arm/mach-footbridge/ebsa285.c-88-\t\tif (!led)\n--\narch/arm/mach-footbridge/netwinder-hw.c=720=static int __init netwinder_leds_init(void)\n--\narch/arm/mach-footbridge/netwinder-hw.c-729-\narch/arm/mach-footbridge/netwinder-hw.c:730:\t\tled = kzalloc_obj(*led);\narch/arm/mach-footbridge/netwinder-hw.c-731-\t\tif (!led)\n--\narch/arm/mach-imx/mmdc.c=473=static int imx_mmdc_perf_init(struct platform_device *pdev, void __iomem *mmdc_base,\n--\narch/arm/mach-imx/mmdc.c-479-\narch/arm/mach-imx/mmdc.c:480:\tpmu_mmdc = kzalloc_obj(*pmu_mmdc);\narch/arm/mach-imx/mmdc.c-481-\tif (!pmu_mmdc) {\n--\narch/arm/mach-mvebu/board-v7.c=114=static void __init i2c_quirk(void)\n--\narch/arm/mach-mvebu/board-v7.c-129-\narch/arm/mach-mvebu/board-v7.c:130:\t\tnew_compat = kzalloc_obj(*new_compat);\narch/arm/mach-mvebu/board-v7.c-131-\n--\narch/arm/mach-mvebu/coherency.c=163=static void __init armada_375_380_coherency_init(struct device_node *np)\n--\narch/arm/mach-mvebu/coherency.c-187-\narch/arm/mach-mvebu/coherency.c:188:\t\tp = kzalloc_obj(*p);\narch/arm/mach-mvebu/coherency.c-189-\t\tp-\u003ename = kstrdup(\"arm,io-coherent\", GFP_KERNEL);\n--\narch/arm/mach-mvebu/mvebu-soc-id.c=148=static int __init mvebu_soc_device(void)\n--\narch/arm/mach-mvebu/mvebu-soc-id.c-156-\narch/arm/mach-mvebu/mvebu-soc-id.c:157:\tsoc_dev_attr = kzalloc_obj(*soc_dev_attr);\narch/arm/mach-mvebu/mvebu-soc-id.c-158-\tif (!soc_dev_attr)\n--\narch/arm/mach-mxs/mach-mxs.c=380=static void __init mxs_machine_init(void)\n--\narch/arm/mach-mxs/mach-mxs.c-389-\narch/arm/mach-mxs/mach-mxs.c:390:\tsoc_dev_attr = kzalloc_obj(*soc_dev_attr);\narch/arm/mach-mxs/mach-mxs.c-391-\tif (!soc_dev_attr)\n--\narch/arm/mach-omap1/dma.c=294=static int __init omap1_system_dma_init(void)\n--\narch/arm/mach-omap1/dma.c-321-\narch/arm/mach-omap1/dma.c:322:\td = kzalloc_obj(*d);\narch/arm/mach-omap1/dma.c-323-\tif (!d) {\n--\narch/arm/mach-omap1/mcbsp.c=292=static void omap_mcbsp_register_board_cfg(struct resource *res, int res_count,\n--\narch/arm/mach-omap1/mcbsp.c-296-\narch/arm/mach-omap1/mcbsp.c:297:\tomap_mcbsp_devices = kzalloc_objs(struct platform_device *, size);\narch/arm/mach-omap1/mcbsp.c-298-\tif (!omap_mcbsp_devices) {\n--\narch/arm/mach-omap1/timer.c=51=static int __init omap1_dm_timer_init(void)\n--\narch/arm/mach-omap1/timer.c-127-\narch/arm/mach-omap1/timer.c:128:\t\tpdata = kzalloc_obj(*pdata);\narch/arm/mach-omap1/timer.c-129-\t\tif (!pdata) {\n--\narch/arm/mach-omap2/clkt2xxx_virt_prcm_set.c=230=void omap2xxx_clkt_vps_init(void)\n--\narch/arm/mach-omap2/clkt2xxx_virt_prcm_set.c-239-\narch/arm/mach-omap2/clkt2xxx_virt_prcm_set.c:240:\thw = kzalloc_obj(*hw);\narch/arm/mach-omap2/clkt2xxx_virt_prcm_set.c-241-\tif (!hw)\n--\narch/arm/mach-omap2/id.c=786=void __init omap_soc_device_init(void)\n--\narch/arm/mach-omap2/id.c-790-\narch/arm/mach-omap2/id.c:791:\tsoc_dev_attr = kzalloc_obj(*soc_dev_attr);\narch/arm/mach-omap2/id.c-792-\tif (!soc_dev_attr)\n--\narch/arm/mach-omap2/omap_device.c=131=static int omap_device_build_from_dt(struct platform_device *pdev)\n--\narch/arm/mach-omap2/omap_device.c-158-\narch/arm/mach-omap2/omap_device.c:159:\thwmods = kzalloc_objs(struct omap_hwmod *, oh_cnt);\narch/arm/mach-omap2/omap_device.c-160-\tif (!hwmods) {\n--\narch/arm/mach-omap2/omap_hwmod.c=3381=static int omap_hwmod_allocate_module(struct device *dev, struct omap_hwmod *oh,\n--\narch/arm/mach-omap2/omap_hwmod.c-3394-\narch/arm/mach-omap2/omap_hwmod.c:3395:\tsysc = kzalloc_obj(*sysc);\narch/arm/mach-omap2/omap_hwmod.c-3396-\tif (!sysc)\n--\narch/arm/mach-omap2/omap_hwmod.c-3424-\tif (list_empty(\u0026oh-\u003eslave_ports)) {\narch/arm/mach-omap2/omap_hwmod.c:3425:\t\toi = kzalloc_obj(*oi);\narch/arm/mach-omap2/omap_hwmod.c-3426-\t\tif (!oi)\n--\narch/arm/mach-omap2/omap_hwmod.c=3513=int omap_hwmod_init_module(struct device *dev,\n--\narch/arm/mach-omap2/omap_hwmod.c-3527-\tif (!oh) {\narch/arm/mach-omap2/omap_hwmod.c:3528:\t\toh = kzalloc_obj(*oh);\narch/arm/mach-omap2/omap_hwmod.c-3529-\t\tif (!oh)\n--\narch/arm/mach-omap2/omap_hwmod.c-3538-\narch/arm/mach-omap2/omap_hwmod.c:3539:\t\toh-\u003eclass = kzalloc_obj(*oh-\u003eclass);\narch/arm/mach-omap2/omap_hwmod.c-3540-\t\tif (!oh-\u003eclass) {\n--\narch/arm/mach-omap2/pm33xx-core.c=379=static int __init amx3_idle_init(struct device_node *cpu_node, int cpu)\n--\narch/arm/mach-omap2/pm33xx-core.c-412-\narch/arm/mach-omap2/pm33xx-core.c:413:\tidle_states = kzalloc_objs(*idle_states, state_count);\narch/arm/mach-omap2/pm33xx-core.c-414-\tif (!idle_states)\n--\narch/arm/mach-omap2/sr_device.c=30=static void __init sr_set_nvalues(struct omap_volt_data *volt_data,\n--\narch/arm/mach-omap2/sr_device.c-41-\narch/arm/mach-omap2/sr_device.c:42:\tnvalue_table = kzalloc_objs(*nvalue_table, count);\narch/arm/mach-omap2/sr_device.c-43-\tif (!nvalue_table)\n--\narch/arm/mach-orion5x/pci.c=139=static int __init pcie_setup(struct pci_sys_data *sys)\n--\narch/arm/mach-orion5x/pci.c-171-\t */\narch/arm/mach-orion5x/pci.c:172:\tres = kzalloc_obj(struct resource);\narch/arm/mach-orion5x/pci.c-173-\tif (!res)\n--\narch/arm/mach-orion5x/pci.c=466=static int __init pci_setup(struct pci_sys_data *sys)\n--\narch/arm/mach-orion5x/pci.c-492-\t */\narch/arm/mach-orion5x/pci.c:493:\tres = kzalloc_obj(struct resource);\narch/arm/mach-orion5x/pci.c-494-\tif (!res)\n--\narch/arm/mach-rpc/ecard.c=689=static struct expansion_card *__init ecard_alloc_card(int type, int slot)\n--\narch/arm/mach-rpc/ecard.c-694-\narch/arm/mach-rpc/ecard.c:695:\tec = kzalloc_obj(ecard_t);\narch/arm/mach-rpc/ecard.c-696-\tif (!ec) {\n--\narch/arm/mach-sa1100/clock.c=93=int __init sa11xx_clk_init(void)\n--\narch/arm/mach-sa1100/clock.c-109-\narch/arm/mach-sa1100/clock.c:110:\thw = kzalloc_obj(*hw);\narch/arm/mach-sa1100/clock.c-111-\tif (!hw)\n--\narch/arm/mach-sa1100/clock.c-131-\narch/arm/mach-sa1100/clock.c:132:\thw = kzalloc_obj(*hw);\narch/arm/mach-sa1100/clock.c-133-\tif (!hw)\n--\narch/arm/mach-sa1100/generic.c=317=int __init sa11x0_register_fixed_regulator(int n,\n--\narch/arm/mach-sa1100/generic.c-323-\narch/arm/mach-sa1100/generic.c:324:\tcfg-\u003einit_data = id = kzalloc_obj(*cfg-\u003einit_data);\narch/arm/mach-sa1100/generic.c-325-\tif (!cfg-\u003einit_data)\n--\narch/arm/mach-sa1100/neponset.c=225=static int neponset_probe(struct platform_device *dev)\n--\narch/arm/mach-sa1100/neponset.c-278-\narch/arm/mach-sa1100/neponset.c:279:\td = kzalloc_obj(*d);\narch/arm/mach-sa1100/neponset.c-280-\tif (!d) {\n--\narch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c=141=static int __init rcar_gen2_regulator_quirk(void)\n--\narch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c-166-\narch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c:167:\t\tquirk = kzalloc_obj(*quirk);\narch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c-168-\t\tif (!quirk) {\n--\narch/arm/mach-versatile/spc.c=393=static int ve_spc_populate_opps(uint32_t cluster)\n--\narch/arm/mach-versatile/spc.c-397-\narch/arm/mach-versatile/spc.c:398:\topps = kzalloc_objs(*opps, MAX_OPPS);\narch/arm/mach-versatile/spc.c-399-\tif (!opps)\n--\narch/arm/mach-versatile/spc.c=442=int __init ve_spc_init(void __iomem *baseaddr, u32 a15_clusid, int irq)\n--\narch/arm/mach-versatile/spc.c-444-\tint ret;\narch/arm/mach-versatile/spc.c:445:\tinfo = kzalloc_obj(*info);\narch/arm/mach-versatile/spc.c-446-\tif (!info)\n--\narch/arm/mach-versatile/spc.c=523=static struct clk *ve_spc_clk_register(struct device *cpu_dev)\n--\narch/arm/mach-versatile/spc.c-527-\narch/arm/mach-versatile/spc.c:528:\tspc = kzalloc_obj(*spc);\narch/arm/mach-versatile/spc.c-529-\tif (!spc)\n--\narch/arm/mach-versatile/versatile.c=123=static void __init versatile_dt_pci_init(void)\n--\narch/arm/mach-versatile/versatile.c-144-\narch/arm/mach-versatile/versatile.c:145:\tnewprop = kzalloc_obj(*newprop);\narch/arm/mach-versatile/versatile.c-146-\tif (!newprop)\n--\narch/arm/mach-zynq/common.c=105=static void __init zynq_init_machine(void)\n--\narch/arm/mach-zynq/common.c-110-\narch/arm/mach-zynq/common.c:111:\tsoc_dev_attr = kzalloc_obj(*soc_dev_attr);\narch/arm/mach-zynq/common.c-112-\tif (!soc_dev_attr)\n--\narch/arm/mm/cache-l2x0-pmu.c=503=static __init int l2x0_pmu_init(void)\n--\narch/arm/mm/cache-l2x0-pmu.c-509-\narch/arm/mm/cache-l2x0-pmu.c:510:\tl2x0_pmu = kzalloc_obj(*l2x0_pmu);\narch/arm/mm/cache-l2x0-pmu.c-511-\tif (!l2x0_pmu) {\n--\narch/arm/mm/cache-uniphier.c=315=static int __init __uniphier_cache_init(struct device_node *np,\n--\narch/arm/mm/cache-uniphier.c-344-\narch/arm/mm/cache-uniphier.c:345:\tdata = kzalloc_obj(*data);\narch/arm/mm/cache-uniphier.c-346-\tif (!data)\n--\narch/arm/mm/dma-mapping.c=533=static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,\n--\narch/arm/mm/dma-mapping.c-560-\narch/arm/mm/dma-mapping.c:561:\tbuf = kzalloc_obj(*buf,\narch/arm/mm/dma-mapping.c-562-\t\t\t gfp \u0026 ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM));\n--\narch/arm/mm/dma-mapping.c=1487=arm_iommu_create_mapping(struct device *dev, dma_addr_t base, u64 size)\n--\narch/arm/mm/dma-mapping.c-1506-\narch/arm/mm/dma-mapping.c:1507:\tmapping = kzalloc_obj(struct dma_iommu_mapping);\narch/arm/mm/dma-mapping.c-1508-\tif (!mapping)\n--\narch/arm/xen/enlighten.c=316=int __init arch_xen_unpopulated_init(struct resource **res)\n--\narch/arm/xen/enlighten.c-343-\narch/arm/xen/enlighten.c:344:\tregs = kzalloc_objs(*regs, nr_reg);\narch/arm/xen/enlighten.c-345-\tif (!regs) {\n--\narch/arm/xen/enlighten.c-387-\narch/arm/xen/enlighten.c:388:\t\ttmp_res = kzalloc_obj(*tmp_res);\narch/arm/xen/enlighten.c-389-\t\tif (!tmp_res) {\n--\narch/arm/xen/p2m.c=150=bool __set_phys_to_machine_multi(unsigned long pfn,\n--\narch/arm/xen/p2m.c-178-\narch/arm/xen/p2m.c:179:\tp2m_entry = kzalloc_obj(*p2m_entry, GFP_NOWAIT);\narch/arm/xen/p2m.c-180-\tif (!p2m_entry)\n--\narch/arm64/kernel/vdso.c=68=static int __init __vdso_init(enum vdso_abi abi)\n--\narch/arm64/kernel/vdso.c-83-\narch/arm64/kernel/vdso.c:84:\tvdso_pagelist = kzalloc_objs(struct page *, vdso_info[abi].vdso_pages);\narch/arm64/kernel/vdso.c-85-\tif (vdso_pagelist == NULL)\n--\narch/arm64/kvm/mmu.c=480=static int share_pfn_hyp(u64 pfn)\n--\narch/arm64/kvm/mmu.c-492-\narch/arm64/kvm/mmu.c:493:\tthis = kzalloc_obj(*this);\narch/arm64/kvm/mmu.c-494-\tif (!this) {\n--\narch/arm64/kvm/mmu.c=981=int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long type)\n--\narch/arm64/kvm/mmu.c-1007-\narch/arm64/kvm/mmu.c:1008:\tpgt = kzalloc_obj(*pgt, GFP_KERNEL_ACCOUNT);\narch/arm64/kvm/mmu.c-1009-\tif (!pgt)\n--\narch/arm64/kvm/mmu.c=1180=int topup_hyp_memcache(struct kvm_hyp_memcache *mc, unsigned long min_pages)\n--\narch/arm64/kvm/mmu.c-1185-\tif (!mc-\u003emapping) {\narch/arm64/kvm/mmu.c:1186:\t\tmc-\u003emapping = kzalloc_obj(struct pkvm_mapping,\narch/arm64/kvm/mmu.c-1187-\t\t\t\t\t GFP_KERNEL_ACCOUNT);\n--\narch/arm64/kvm/mmu.c=2510=int __init kvm_mmu_init(u32 hyp_va_bits)\n--\narch/arm64/kvm/mmu.c-2543-\narch/arm64/kvm/mmu.c:2544:\thyp_pgtable = kzalloc_obj(*hyp_pgtable);\narch/arm64/kvm/mmu.c-2545-\tif (!hyp_pgtable) {\n--\narch/arm64/kvm/nested.c=1328=int kvm_vcpu_allocate_vncr_tlb(struct kvm_vcpu *vcpu)\n--\narch/arm64/kvm/nested.c-1333-\tif (!vcpu-\u003earch.vncr_tlb) {\narch/arm64/kvm/nested.c:1334:\t\tstruct vncr_tlb *vt = kzalloc_obj(*vcpu-\u003earch.vncr_tlb,\narch/arm64/kvm/nested.c-1335-\t\t\t\t\t\t GFP_KERNEL_ACCOUNT);\n--\narch/arm64/kvm/nested.c=1793=int kvm_init_nv_sysregs(struct kvm_vcpu *vcpu)\n--\narch/arm64/kvm/nested.c-1802-\narch/arm64/kvm/nested.c:1803:\tkvm-\u003earch.sysreg_masks = kzalloc_obj(*(kvm-\u003earch.sysreg_masks),\narch/arm64/kvm/nested.c-1804-\t\t\t\t\t GFP_KERNEL_ACCOUNT);\n--\narch/arm64/kvm/ptdump.c=116=static struct kvm_ptdump_guest_state *kvm_ptdump_parser_create(struct kvm_s2_mmu *mmu)\n--\narch/arm64/kvm/ptdump.c-121-\narch/arm64/kvm/ptdump.c:122:\tst = kzalloc_obj(struct kvm_ptdump_guest_state, GFP_KERNEL_ACCOUNT);\narch/arm64/kvm/ptdump.c-123-\tif (!st)\n--\narch/arm64/kvm/vgic/vgic-init.c=207=static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)\n--\narch/arm64/kvm/vgic/vgic-init.c-213-\tdist-\u003eactive_spis = (atomic_t)ATOMIC_INIT(0);\narch/arm64/kvm/vgic/vgic-init.c:214:\tdist-\u003espis = kzalloc_objs(struct vgic_irq, nr_spis, GFP_KERNEL_ACCOUNT);\narch/arm64/kvm/vgic/vgic-init.c-215-\tif (!dist-\u003espis)\n--\narch/arm64/kvm/vgic/vgic-init.c=316=static int vgic_allocate_private_irqs_locked(struct kvm_vcpu *vcpu, u32 type)\n--\narch/arm64/kvm/vgic/vgic-init.c-331-\narch/arm64/kvm/vgic/vgic-init.c:332:\tvgic_cpu-\u003eprivate_irqs = kzalloc_objs(struct vgic_irq,\narch/arm64/kvm/vgic/vgic-init.c-333-\t\t\t\t\t num_private_irqs,\n--\narch/arm64/kvm/vgic/vgic-irqfd.c=142=int kvm_vgic_setup_default_irq_routing(struct kvm *kvm)\n--\narch/arm64/kvm/vgic/vgic-irqfd.c-148-\narch/arm64/kvm/vgic/vgic-irqfd.c:149:\tentries = kzalloc_objs(*entries, nr, GFP_KERNEL_ACCOUNT);\narch/arm64/kvm/vgic/vgic-irqfd.c-150-\tif (!entries)\n--\narch/arm64/kvm/vgic/vgic-its.c=76=static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid,\n--\narch/arm64/kvm/vgic/vgic-its.c-87-\narch/arm64/kvm/vgic/vgic-its.c:88:\tirq = kzalloc_obj(struct vgic_irq, GFP_KERNEL_ACCOUNT);\narch/arm64/kvm/vgic/vgic-its.c-89-\tif (!irq)\n--\narch/arm64/kvm/vgic/vgic-its.c=962=static int vgic_its_alloc_collection(struct vgic_its *its,\n--\narch/arm64/kvm/vgic/vgic-its.c-967-\narch/arm64/kvm/vgic/vgic-its.c:968:\tcollection = kzalloc_obj(*collection, GFP_KERNEL_ACCOUNT);\narch/arm64/kvm/vgic/vgic-its.c-969-\tif (!collection)\n--\narch/arm64/kvm/vgic/vgic-its.c=1006=static struct its_ite *vgic_its_alloc_ite(struct its_device *device,\n--\narch/arm64/kvm/vgic/vgic-its.c-1011-\narch/arm64/kvm/vgic/vgic-its.c:1012:\tite = kzalloc_obj(*ite, GFP_KERNEL_ACCOUNT);\narch/arm64/kvm/vgic/vgic-its.c-1013-\tif (!ite)\n--\narch/arm64/kvm/vgic/vgic-its.c=1133=static struct its_device *vgic_its_alloc_device(struct vgic_its *its,\n--\narch/arm64/kvm/vgic/vgic-its.c-1138-\narch/arm64/kvm/vgic/vgic-its.c:1139:\tdevice = kzalloc_obj(*device, GFP_KERNEL_ACCOUNT);\narch/arm64/kvm/vgic/vgic-its.c-1140-\tif (!device)\n--\narch/arm64/kvm/vgic/vgic-its.c=1846=static int vgic_its_create(struct kvm_device *dev, u32 type)\n--\narch/arm64/kvm/vgic/vgic-its.c-1853-\narch/arm64/kvm/vgic/vgic-its.c:1854:\tits = kzalloc_obj(struct vgic_its, GFP_KERNEL_ACCOUNT);\narch/arm64/kvm/vgic/vgic-its.c-1855-\tif (!its)\n--\narch/arm64/kvm/vgic/vgic-mmio-v3.c=886=static int vgic_v3_alloc_redist_region(struct kvm *kvm, uint32_t index,\n--\narch/arm64/kvm/vgic/vgic-mmio-v3.c-931-\narch/arm64/kvm/vgic/vgic-mmio-v3.c:932:\trdreg = kzalloc_obj(*rdreg, GFP_KERNEL_ACCOUNT);\narch/arm64/kvm/vgic/vgic-mmio-v3.c-933-\tif (!rdreg)\n--\narch/arm64/kvm/vgic/vgic-v4.c=242=int vgic_v4_init(struct kvm *kvm)\n--\narch/arm64/kvm/vgic/vgic-v4.c-258-\narch/arm64/kvm/vgic/vgic-v4.c:259:\tdist-\u003eits_vm.vpes = kzalloc_objs(*dist-\u003eits_vm.vpes, nr_vcpus,\narch/arm64/kvm/vgic/vgic-v4.c-260-\t\t\t\t\t GFP_KERNEL_ACCOUNT);\n--\narch/arm64/net/bpf_jit_comp.c=2080=struct bpf_prog *bpf_int_jit_compile(struct bpf_verifier_env *env, struct bpf_prog *prog)\n--\narch/arm64/net/bpf_jit_comp.c-2101-\tif (!jit_data) {\narch/arm64/net/bpf_jit_comp.c:2102:\t\tjit_data = kzalloc_obj(*jit_data);\narch/arm64/net/bpf_jit_comp.c-2103-\t\tif (!jit_data)\n--\narch/csky/kernel/vdso.c=17=static int __init vdso_init(void)\n--\narch/csky/kernel/vdso.c-22-\tvdso_pagelist =\narch/csky/kernel/vdso.c:23:\t\tkzalloc_objs(struct page *, vdso_pages);\narch/csky/kernel/vdso.c-24-\tif (unlikely(vdso_pagelist == NULL)) {\n--\narch/loongarch/kernel/setup.c=466=static int __init add_legacy_isa_io(struct fwnode_handle *fwnode,\n--\narch/loongarch/kernel/setup.c-472-\narch/loongarch/kernel/setup.c:473:\trange = kzalloc_obj(*range, GFP_ATOMIC);\narch/loongarch/kernel/setup.c-474-\tif (!range)\n--\narch/loongarch/kernel/vdso.c=45=static int __init init_vdso(void)\n--\narch/loongarch/kernel/vdso.c-55-\tvdso_info.code_mapping.pages =\narch/loongarch/kernel/vdso.c:56:\t\tkzalloc_objs(struct page *, vdso_info.size / PAGE_SIZE);\narch/loongarch/kernel/vdso.c-57-\n--\narch/loongarch/kvm/intc/eiointc.c=614=static int kvm_eiointc_create(struct kvm_device *dev, u32 type)\n--\narch/loongarch/kvm/intc/eiointc.c-624-\narch/loongarch/kvm/intc/eiointc.c:625:\ts = kzalloc_obj(struct loongarch_eiointc);\narch/loongarch/kvm/intc/eiointc.c-626-\tif (!s)\n--\narch/loongarch/kvm/intc/ipi.c=394=static int kvm_ipi_create(struct kvm_device *dev, u32 type)\n--\narch/loongarch/kvm/intc/ipi.c-411-\narch/loongarch/kvm/intc/ipi.c:412:\ts = kzalloc_obj(struct loongarch_ipi);\narch/loongarch/kvm/intc/ipi.c-413-\tif (!s)\n\n"
} |
| 15/3 | 2026/08/10 12:22 | llm | kmsan-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 15648 output: 34 thoughts: 1479 Thoughts: **Analyzing the Patch: GUP Test Data Structure** Okay, so looking at this patch, I see they're swapping out the global variables for the GUP test with a per-file structure. That's a good change, makes things cleaner and potentially allows for multiple concurrent tests, and doesn't introduce global state. The key here is the `kzalloc_obj` call in `gup_test_open`. That's essentially the same as `kzalloc(sizeof(*data), GFP_KERNEL)`. So, that zero-initializes the `gup_test_data` structure, which is important. This ensures everything starts clean, which avoids any potential issues with uninitialized memory. The mutex is being properly initialized with `mutex_init`, which is correct. The `file->private_data` assignment is standard practice, associating the data structure with the file operation. The core of this patch seems to involve moving the page array and mutex from global scope to this per-file structure. The key functions, `pin_longterm_test_start` and `pin_longterm_test_read`, now take a `struct gup_test_data *` as an argument. Looking at the changes, I can see that the code is correctly updating to use the per-file data; replacing all instances of the old global variable references to the data structure. The part that caught my attention was the `copy_to_user` in `pin_longterm_test_read`. But it's transferring data that came from user space originally. It's essentially "round-tripping" user data back to user space via the pinned pages. This doesn't introduce any new information leaks, as the user memory is the source of the data, and it's simply copied back to the same address space. It's just the storage for that memory (the page pointers) that's been changed. Now, let's double-check the allocations. The `pages` array itself isn't directly shown here, I'm going to have to dig around `pin_longterm_test_start` for that. Ah, here it is: the memory for the `pages` array is allocated with `kvmalloc_array`. That's a dynamically allocated kernel memory array. It makes sense that `kvfree` is used later on to release that allocation. So, summing up, this patch is a clean refactoring. It moves the test's state into a per-file structure, properly initializes that structure via `kzalloc_obj`, and correctly handles memory management and the round-trip of user data to user space. It doesn't introduce any uninitialized memory usage because of the zeroing and initialization, and the data being copied is originating from user space. It's safe. |
| 16/3 | 2026/08/10 12:22 | tool | grepper |
0mError:no matches Args: {
"Expression": "kvmalloc_array.*pages",
"PathPrefix": "mm/gup_test.c"
}Results: {
"error": "no matches"
} |
| 17/3 | 2026/08/10 12:22 | llm | kmsan-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 17770 output: 37 thoughts: 26 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: **Analyzing the GUP Long-Term Test Start** Okay, let's dive straight into `pin_longterm_test_start` within `mm/gup_test.c`. I need to get a clear picture of how this long-term test sequence begins for the GUP (get_user_pages) subsystem. What are the initial setup steps? What parameters are being configured? Are there any obvious areas that might be prone to contention or race conditions that I should be aware of immediately? I want to understand the framework this test utilizes. I'll be looking for how it sets up the memory regions, any use of specialized page structures or mappings, and how the test harnesses the GUP interface to simulate realistic or stressful scenarios. I'm assuming it's probably using a combination of direct and indirect GUP calls, perhaps with pinned pages to mimic some real-world application behavior. The goal here is to establish the baseline and the test environment; then, from there, I can figure out the specifics. |
| 18/3 | 2026/08/10 12:22 | tool | read-file |
0mArgs:{
"File": "mm/gup_test.c",
"FirstLine": 220,
"LineCount": 100
}Results: {
"Contents": " 220:\t\t\tif (data-\u003elongterm_nr_pages)\n 221:\t\t\t\tunpin_user_pages(data-\u003elongterm_pages,\n 222:\t\t\t\t\t\t data-\u003elongterm_nr_pages);\n 223:\t\t\tkvfree(data-\u003elongterm_pages);\n 224:\t\t\tdata-\u003elongterm_pages = NULL;\n 225:\t\t\tdata-\u003elongterm_nr_pages = 0;\n 226:\t\t}\n 227:\t}\n 228:\t\n 229:\tstatic inline int pin_longterm_test_start(struct gup_test_data *data,\n 230:\t\t\tunsigned long arg)\n 231:\t{\n 232:\t\tlong nr_pages, cur_pages, addr, remaining_pages;\n 233:\t\tint gup_flags = FOLL_LONGTERM;\n 234:\t\tstruct pin_longterm_test args;\n 235:\t\tstruct page **pages;\n 236:\t\tint ret = 0;\n 237:\t\tbool fast;\n 238:\t\n 239:\t\tif (data-\u003elongterm_pages)\n 240:\t\t\treturn -EINVAL;\n 241:\t\n 242:\t\tif (copy_from_user(\u0026args, (void __user *)arg, sizeof(args)))\n 243:\t\t\treturn -EFAULT;\n 244:\t\n 245:\t\tif (args.flags \u0026\n 246:\t\t ~(PIN_LONGTERM_TEST_FLAG_USE_WRITE|PIN_LONGTERM_TEST_FLAG_USE_FAST))\n 247:\t\t\treturn -EINVAL;\n 248:\t\tif (!IS_ALIGNED(args.addr | args.size, PAGE_SIZE))\n 249:\t\t\treturn -EINVAL;\n 250:\t\tif (args.size \u003e LONG_MAX)\n 251:\t\t\treturn -EINVAL;\n 252:\t\tnr_pages = args.size / PAGE_SIZE;\n 253:\t\tif (!nr_pages)\n 254:\t\t\treturn -EINVAL;\n 255:\t\n 256:\t\tpages = kvcalloc(nr_pages, sizeof(void *), GFP_KERNEL);\n 257:\t\tif (!pages)\n 258:\t\t\treturn -ENOMEM;\n 259:\t\n 260:\t\tif (args.flags \u0026 PIN_LONGTERM_TEST_FLAG_USE_WRITE)\n 261:\t\t\tgup_flags |= FOLL_WRITE;\n 262:\t\tfast = !!(args.flags \u0026 PIN_LONGTERM_TEST_FLAG_USE_FAST);\n 263:\t\n 264:\t\tif (!fast \u0026\u0026 mmap_read_lock_killable(current-\u003emm)) {\n 265:\t\t\tkvfree(pages);\n 266:\t\t\treturn -EINTR;\n 267:\t\t}\n 268:\t\n 269:\t\tdata-\u003elongterm_pages = pages;\n 270:\t\tdata-\u003elongterm_nr_pages = 0;\n 271:\t\n 272:\t\twhile (nr_pages - data-\u003elongterm_nr_pages) {\n 273:\t\t\tremaining_pages = nr_pages - data-\u003elongterm_nr_pages;\n 274:\t\t\taddr = args.addr + data-\u003elongterm_nr_pages * PAGE_SIZE;\n 275:\t\n 276:\t\t\tif (fast)\n 277:\t\t\t\tcur_pages = pin_user_pages_fast(addr, remaining_pages,\n 278:\t\t\t\t\t\t\t\tgup_flags, pages);\n 279:\t\t\telse\n 280:\t\t\t\tcur_pages = pin_user_pages(addr, remaining_pages,\n 281:\t\t\t\t\t\t\t gup_flags, pages);\n 282:\t\t\tif (cur_pages \u003c 0) {\n 283:\t\t\t\tpin_longterm_test_stop(data);\n 284:\t\t\t\tret = cur_pages;\n 285:\t\t\t\tbreak;\n 286:\t\t\t}\n 287:\t\t\tdata-\u003elongterm_nr_pages += cur_pages;\n 288:\t\t\tpages += cur_pages;\n 289:\t\t}\n 290:\t\n 291:\t\tif (!fast)\n 292:\t\t\tmmap_read_unlock(current-\u003emm);\n 293:\t\treturn ret;\n 294:\t}\n 295:\t\n 296:\tstatic inline int pin_longterm_test_read(struct gup_test_data *data,\n 297:\t\t\tunsigned long arg)\n 298:\t{\n 299:\t\t__u64 user_addr;\n 300:\t\tunsigned long i;\n 301:\t\n 302:\t\tif (!data-\u003elongterm_pages)\n 303:\t\t\treturn -EINVAL;\n 304:\t\n 305:\t\tif (copy_from_user(\u0026user_addr, (void __user *)arg, sizeof(user_addr)))\n 306:\t\t\treturn -EFAULT;\n 307:\t\n 308:\t\tfor (i = 0; i \u003c data-\u003elongterm_nr_pages; i++) {\n 309:\t\t\tvoid *addr = kmap_local_page(data-\u003elongterm_pages[i]);\n 310:\t\t\tunsigned long ret;\n 311:\t\n 312:\t\t\tret = copy_to_user((void __user *)(unsigned long)user_addr, addr,\n 313:\t\t\t\t\t PAGE_SIZE);\n 314:\t\t\tkunmap_local(addr);\n 315:\t\t\tif (ret)\n 316:\t\t\t\treturn -EFAULT;\n 317:\t\t\tuser_addr += PAGE_SIZE;\n 318:\t\t}\n 319:\t\treturn 0;\n"
} |
| 19/3 | 2026/08/10 12:22 | llm | kmsan-evaluator |
0mModel:gemini-3.1-pro-preview Args: null Results: null Tokens: input: 19549 output: 217 thoughts: 405 Thoughts: **My Assessment of the Code Changes** Okay, so I've looked over this patch. My initial thought is that the allocation of the `pages` array using `kvcalloc` and the `struct gup_test_data` with `kzalloc_obj`, with their zero-initialization, are good signs. It means we're starting clean, which helps mitigate potential uninitialized memory reads or information leaks. I can see no immediate red flags in that area. The patch appears to be focused on structural changes – specifically, moving global state to a per-file basis. That's a reasonable refactoring approach, but it can sometimes introduce subtle bugs. However, based on my understanding of the code, any issues introduced by the change would likely manifest as either use-after-free, double-free, or memory leaks. Given that these kinds of bugs are typically caught by KASAN or standard leak detectors, I don't see a strong justification for a dedicated KMSAN fuzzing session at this point. I'm reasonably confident the existing tools will catch any issues. I'm going to quickly double-check the `gup_test_open` and `gup_test_release` functions to make sure there are no missed initializations or improper cleanup. Hmm, let's see... Yep, `gup_test_open` allocates the `data` struct with `kzalloc_obj` and initializes the mutex, assigns `data` to the file's private data field. The `gup_test_release` function properly calls the `pin_longterm_test_stop`, destroys the mutex, and frees the data structure, and nulls the private data field. Everything is initialized correctly and deallocated appropriately. Alright, after this quick scan, I'm confident in saying that no KMSAN is needed. The code looks sound and well-managed. |
| 20/3 | 2026/08/10 12:22 | tool | set-results |
0mArgs:{
"KMSANReasoning": "The patch refactors the `pin_longterm_test` in `mm/gup_test.c` to use a per-file data structure (`struct gup_test_data`) instead of global variables, allowing concurrent users of the gup_test ioctl. The new structure is allocated using `kzalloc_obj`, which zero-initializes all fields. The array of page pointers is allocated using `kvcalloc`, which also zero-initializes the memory. The only data copied to user space is the content of the pinned user pages, which is identical to the pre-patch behavior and does not leak kernel memory. Any potential bugs introduced by these changes (e.g., use-after-free, double free, or memory leaks) would be effectively caught by KASAN and standard memory leak detectors. There is no risk of uninitialized memory usage or info-leaks that would require KMSAN.",
"NeedsKMSAN": false
}Results: {
"KMSANReasoning": "The patch refactors the `pin_longterm_test` in `mm/gup_test.c` to use a per-file data structure (`struct gup_test_data`) instead of global variables, allowing concurrent users of the gup_test ioctl. The new structure is allocated using `kzalloc_obj`, which zero-initializes all fields. The array of page pointers is allocated using `kvcalloc`, which also zero-initializes the memory. The only data copied to user space is the content of the pinned user pages, which is identical to the pre-patch behavior and does not leak kernel memory. Any potential bugs introduced by these changes (e.g., use-after-free, double free, or memory leaks) would be effectively caught by KASAN and standard memory leak detectors. There is no risk of uninitialized memory usage or info-leaks that would require KMSAN.",
"NeedsKMSAN": false
} |
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