AI Trajectory

Trajectory: (Expand/Collapse All)
Seq	Timestamp	Type	Name	Duration
0/0	2026/07/19 06:11	flow	patch-triage	0m Args: null Results: { "EnableConfigs": [ "FS_ENCRYPTION_INLINE_CRYPT", "BLK_INLINE_ENCRYPTION", "F2FS_FS" ], "FocusSymbols": [ "fscrypt_select_encryption_impl", "fscrypt_prepare_inline_crypt_key", "fscrypt_destroy_inline_crypt_key", "f2fs_get_devices" ], "Reasoning": "The patch changes how block device arrays are allocated in fscrypt and f2fs, moving from dynamic heap allocation to a fixed-size stack array. This affects inline encryption setup and teardown paths. Fuzzing should focus on these paths to ensure no stack corruption or out-of-bounds access occurs, especially with multiple devices in f2fs.", "WorthFuzzing": true }
1/1	2026/07/19 06:11	action	read-patch-diff	0m Args: null Results: { "PatchDiff": "commit 04976aa1df55caef35adea06fbf33a89d2932359\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Sun Jul 19 06:11:24 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c\nindex 47324062fee514..66b9c9150fed66 100644\n--- a/fs/crypto/inline_crypt.c\n+++ b/fs/crypto/inline_crypt.c\n@@ -22,22 +22,14 @@\n \n #include \"fscrypt_private.h\"\n \n-static struct block_device *fscrypt_get_devices(struct super_block sb,\n-\t\t\t\t\t\t unsigned int num_devs)\n+static unsigned int\n+fscrypt_get_devices(struct super_block sb,\n+\t\t struct block_device devs[FSCRYPT_MAX_DEVICES])\n {\n-\tstruct block_device devs;\n-\n-\tif (sb-\u003es_cop-\u003eget_devices) {\n-\t\tdevs = sb-\u003es_cop-\u003eget_devices(sb, num_devs);\n-\t\tif (devs)\n-\t\t\treturn devs;\n-\t}\n-\tdevs = kmalloc_obj(devs);\n-\tif (!devs)\n-\t\treturn ERR_PTR(-ENOMEM);\n+\tif (sb-\u003es_cop-\u003eget_devices)\n+\t\treturn sb-\u003es_cop-\u003eget_devices(sb, devs);\n \tdevs[0] = sb-\u003es_bdev;\n-\tnum_devs = 1;\n-\treturn devs;\n+\treturn 1;\n }\n \n static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_inode_info ci)\n@@ -96,7 +88,7 @@ int fscrypt_select_encryption_impl(struct fscrypt_inode_info ci,\n \tconst struct inode inode = ci-\u003eci_inode;\n \tstruct super_block sb = inode-\u003ei_sb;\n \tstruct blk_crypto_config crypto_cfg;\n-\tstruct block_device devs;\n+\tstruct block_device devs[FSCRYPT_MAX_DEVICES];\n \tunsigned int num_devs;\n \tunsigned int i;\n \n@@ -135,20 +127,15 @@ int fscrypt_select_encryption_impl(struct fscrypt_inode_info ci,\n \tcrypto_cfg.key_type = is_hw_wrapped_key ?\n \t\tBLK_CRYPTO_KEY_TYPE_HW_WRAPPED : BLK_CRYPTO_KEY_TYPE_RAW;\n \n-\tdevs = fscrypt_get_devices(sb, \u0026num_devs);\n-\tif (IS_ERR(devs))\n-\t\treturn PTR_ERR(devs);\n-\n+\tnum_devs = fscrypt_get_devices(sb, devs);\n \tfor (i = 0; i \u003c num_devs; i++) {\n \t\tif (!blk_crypto_config_supported(devs[i], \u0026crypto_cfg))\n-\t\t\tgoto out_free_devs;\n+\t\t\treturn 0;\n \t}\n \n \tfscrypt_log_blk_crypto_impl(ci-\u003eci_mode, devs, num_devs, \u0026crypto_cfg);\n \n \tci-\u003eci_inlinecrypt = true;\n-out_free_devs:\n-\tkfree(devs);\n \n \treturn 0;\n }\n@@ -164,7 +151,7 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key prep_key,\n \tenum blk_crypto_key_type key_type = is_hw_wrapped ?\n \t\tBLK_CRYPTO_KEY_TYPE_HW_WRAPPED : BLK_CRYPTO_KEY_TYPE_RAW;\n \tstruct blk_crypto_key blk_key;\n-\tstruct block_device devs;\n+\tstruct block_device devs[FSCRYPT_MAX_DEVICES];\n \tunsigned int num_devs;\n \tunsigned int i;\n \tint err;\n@@ -182,17 +169,12 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key prep_key,\n \t}\n \n \t/ Start using blk-crypto on all the filesystem's block devices. /\n-\tdevs = fscrypt_get_devices(sb, \u0026num_devs);\n-\tif (IS_ERR(devs)) {\n-\t\terr = PTR_ERR(devs);\n-\t\tgoto fail;\n-\t}\n+\tnum_devs = fscrypt_get_devices(sb, devs);\n \tfor (i = 0; i \u003c num_devs; i++) {\n \t\terr = blk_crypto_start_using_key(devs[i], blk_key);\n \t\tif (err)\n \t\t\tbreak;\n \t}\n-\tkfree(devs);\n \tif (err) {\n \t\tfscrypt_err(inode, \"error %d starting to use blk-crypto\", err);\n \t\tgoto fail;\n@@ -210,20 +192,21 @@ void fscrypt_destroy_inline_crypt_key(struct super_block sb,\n \t\t\t\t struct fscrypt_prepared_key prep_key)\n {\n \tstruct blk_crypto_key blk_key = prep_key-\u003eblk_key;\n-\tstruct block_device *devs;\n+\tstruct block_device devs[FSCRYPT_MAX_DEVICES];\n \tunsigned int num_devs;\n \tunsigned int i;\n \n \tif (!blk_key)\n \t\treturn;\n \n-\t/* Evict the key from all the filesystem's block devices. /\n-\tdevs = fscrypt_get_devices(sb, \u0026num_devs);\n-\tif (!IS_ERR(devs)) {\n-\t\tfor (i = 0; i \u003c num_devs; i++)\n-\t\t\tblk_crypto_evict_key(devs[i], blk_key);\n-\t\tkfree(devs);\n-\t}\n+\t/\n+\t * Evict the key from all the filesystem's block devices.\n+\t * This must be done before the key is freed.\n+\t /\n+\tnum_devs = fscrypt_get_devices(sb, devs);\n+\tfor (i = 0; i \u003c num_devs; i++)\n+\t\tblk_crypto_evict_key(devs[i], blk_key);\n+\n \tkfree_sensitive(blk_key);\n }\n \ndiff --git a/fs/f2fs/super.c b/fs/f2fs/super.c\nindex 2b8d964111562a..9760e4efeffeca 100644\n--- a/fs/f2fs/super.c\n+++ b/fs/f2fs/super.c\n@@ -3749,24 +3749,27 @@ static bool f2fs_has_stable_inodes(struct super_block sb)\n \treturn true;\n }\n \n-static struct block_device *f2fs_get_devices(struct super_block sb,\n-\t\t\t\t\t unsigned int num_devs)\n+static unsigned int\n+f2fs_get_devices(struct super_block sb,\n+\t\t struct block_device devs[FSCRYPT_MAX_DEVICES])\n {\n \tstruct f2fs_sb_info sbi = F2FS_SB(sb);\n-\tstruct block_device *devs;\n+\tint ndevs;\n \tint i;\n \n-\tif (!f2fs_is_multi_device(sbi))\n-\t\treturn NULL;\n+\tstatic_assert(MAX_DEVICES \u003c= FSCRYPT_MAX_DEVICES);\n \n-\tdevs = kmalloc_objs(devs, sbi-\u003es_ndevs);\n-\tif (!devs)\n-\t\treturn ERR_PTR(-ENOMEM);\n+\tif (!f2fs_is_multi_device(sbi)) {\n+\t\tdevs[0] = sb-\u003es_bdev;\n+\t\treturn 1;\n+\t}\n+\tndevs = sbi-\u003es_ndevs;\n+\tif (WARN_ON_ONCE(ndevs \u003e FSCRYPT_MAX_DEVICES))\n+\t\tndevs = FSCRYPT_MAX_DEVICES;\n \n-\tfor (i = 0; i \u003c sbi-\u003es_ndevs; i++)\n+\tfor (i = 0; i \u003c ndevs; i++)\n \t\tdevs[i] = FDEV(i).bdev;\n-\tnum_devs = sbi-\u003es_ndevs;\n-\treturn devs;\n+\treturn ndevs;\n }\n \n static const struct fscrypt_operations f2fs_cryptops = {\ndiff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h\nindex 54712ec61ffb7c..f6b235cd72b45d 100644\n--- a/include/linux/fscrypt.h\n+++ b/include/linux/fscrypt.h\n@@ -57,6 +57,9 @@ struct fscrypt_name {\n / Maximum value for the third parameter of fscrypt_operations.set_context(). /\n #define FSCRYPT_SET_CONTEXT_MAX_SIZE\t40\n \n+/ Maximum supported number of block devices per filesystem /\n+#define FSCRYPT_MAX_DEVICES\t8\n+\n #ifdef CONFIG_FS_ENCRYPTION\n \n / Crypto operations for filesystems /\n@@ -181,21 +184,20 @@ struct fscrypt_operations {\n \tbool (has_stable_inodes)(struct super_block sb);\n \n \t/\n-\t * Return an array of pointers to the block devices to which the\n-\t * filesystem may write encrypted file contents, NULL if the filesystem\n-\t * only has a single such block device, or an ERR_PTR() on error.\n+\t * Retrieve the list of block devices to which the filesystem may write\n+\t * encrypted file contents.\n \t \n-\t On successful non-NULL return, num_devs is set to the number of\n-\t devices in the returned array. The caller must free the returned\n-\t * array using kfree().\n+\t * This writes the block_device pointers to @devs and returns the count\n+\t * (between 1 and FSCRYPT_MAX_DEVICES inclusively).\n \t \n \t If the filesystem can use multiple block devices (other than block\n \t * devices that aren't used for encrypted file contents, such as\n \t * external journal devices), and wants to support inline encryption,\n \t * then it must implement this function. Otherwise it's not needed.\n \t /\n-\tstruct block_device (get_devices)(struct super_block sb,\n-\t\t\t\t\t unsigned int num_devs);\n+\tunsigned int (get_devices)(\n+\t\tstruct super_block sb,\n+\t\tstruct block_device devs[FSCRYPT_MAX_DEVICES]);\n };\n \n int fscrypt_d_revalidate(struct inode dir, const struct qstr *name,\n" }
2/1	2026/07/19 06:11	agent	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: { "EnableConfigs": [ "FS_ENCRYPTION_INLINE_CRYPT", "BLK_INLINE_ENCRYPTION", "F2FS_FS" ], "FocusSymbols": [ "fscrypt_select_encryption_impl", "fscrypt_prepare_inline_crypt_key", "fscrypt_destroy_inline_crypt_key", "f2fs_get_devices" ], "Reasoning": "The patch changes how block device arrays are allocated in fscrypt and f2fs, moving from dynamic heap allocation to a fixed-size stack array. This affects inline encryption setup and teardown paths. Fuzzing should focus on these paths to ensure no stack corruption or out-of-bounds access occurs, especially with multiple devices in f2fs.", "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). 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. 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. Do not list too generic configs (we already have them enabled). Only list those that specifically cover the modified code. 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 04976aa1df55caef35adea06fbf33a89d2932359 Author: syz-cluster <triage@syzkaller.com> Date: Sun Jul 19 06:11:24 2026 +0000 syz-cluster: applied patch under review diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c index 47324062fee514..66b9c9150fed66 100644 --- a/fs/crypto/inline_crypt.c +++ b/fs/crypto/inline_crypt.c @@ -22,22 +22,14 @@ #include "fscrypt_private.h" -static struct block_device *fscrypt_get_devices(struct super_block sb, - unsigned int num_devs) +static unsigned int +fscrypt_get_devices(struct super_block sb, + struct block_device devs[FSCRYPT_MAX_DEVICES]) { - struct block_device devs; - - if (sb->s_cop->get_devices) { - devs = sb->s_cop->get_devices(sb, num_devs); - if (devs) - return devs; - } - devs = kmalloc_obj(devs); - if (!devs) - return ERR_PTR(-ENOMEM); + if (sb->s_cop->get_devices) + return sb->s_cop->get_devices(sb, devs); devs[0] = sb->s_bdev; - num_devs = 1; - return devs; + return 1; } static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_inode_info ci) @@ -96,7 +88,7 @@ int fscrypt_select_encryption_impl(struct fscrypt_inode_info ci, const struct inode inode = ci->ci_inode; struct super_block sb = inode->i_sb; struct blk_crypto_config crypto_cfg; - struct block_device devs; + struct block_device devs[FSCRYPT_MAX_DEVICES]; unsigned int num_devs; unsigned int i; @@ -135,20 +127,15 @@ int fscrypt_select_encryption_impl(struct fscrypt_inode_info ci, crypto_cfg.key_type = is_hw_wrapped_key ? BLK_CRYPTO_KEY_TYPE_HW_WRAPPED : BLK_CRYPTO_KEY_TYPE_RAW; - devs = fscrypt_get_devices(sb, &num_devs); - if (IS_ERR(devs)) - return PTR_ERR(devs); - + num_devs = fscrypt_get_devices(sb, devs); for (i = 0; i < num_devs; i++) { if (!blk_crypto_config_supported(devs[i], &crypto_cfg)) - goto out_free_devs; + return 0; } fscrypt_log_blk_crypto_impl(ci->ci_mode, devs, num_devs, &crypto_cfg); ci->ci_inlinecrypt = true; -out_free_devs: - kfree(devs); return 0; } @@ -164,7 +151,7 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key prep_key, enum blk_crypto_key_type key_type = is_hw_wrapped ? BLK_CRYPTO_KEY_TYPE_HW_WRAPPED : BLK_CRYPTO_KEY_TYPE_RAW; struct blk_crypto_key blk_key; - struct block_device devs; + struct block_device devs[FSCRYPT_MAX_DEVICES]; unsigned int num_devs; unsigned int i; int err; @@ -182,17 +169,12 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key prep_key, } / Start using blk-crypto on all the filesystem's block devices. / - devs = fscrypt_get_devices(sb, &num_devs); - if (IS_ERR(devs)) { - err = PTR_ERR(devs); - goto fail; - } + num_devs = fscrypt_get_devices(sb, devs); for (i = 0; i < num_devs; i++) { err = blk_crypto_start_using_key(devs[i], blk_key); if (err) break; } - kfree(devs); if (err) { fscrypt_err(inode, "error %d starting to use blk-crypto", err); goto fail; @@ -210,20 +192,21 @@ void fscrypt_destroy_inline_crypt_key(struct super_block sb, struct fscrypt_prepared_key prep_key) { struct blk_crypto_key blk_key = prep_key->blk_key; - struct block_device *devs; + struct block_device devs[FSCRYPT_MAX_DEVICES]; unsigned int num_devs; unsigned int i; if (!blk_key) return; - /* Evict the key from all the filesystem's block devices. / - devs = fscrypt_get_devices(sb, &num_devs); - if (!IS_ERR(devs)) { - for (i = 0; i < num_devs; i++) - blk_crypto_evict_key(devs[i], blk_key); - kfree(devs); - } + / + * Evict the key from all the filesystem's block devices. + * This must be done before the key is freed. + / + num_devs = fscrypt_get_devices(sb, devs); + for (i = 0; i < num_devs; i++) + blk_crypto_evict_key(devs[i], blk_key); + kfree_sensitive(blk_key); } diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 2b8d964111562a..9760e4efeffeca 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -3749,24 +3749,27 @@ static bool f2fs_has_stable_inodes(struct super_block sb) return true; } -static struct block_device *f2fs_get_devices(struct super_block sb, - unsigned int num_devs) +static unsigned int +f2fs_get_devices(struct super_block sb, + struct block_device devs[FSCRYPT_MAX_DEVICES]) { struct f2fs_sb_info sbi = F2FS_SB(sb); - struct block_device *devs; + int ndevs; int i; - if (!f2fs_is_multi_device(sbi)) - return NULL; + static_assert(MAX_DEVICES <= FSCRYPT_MAX_DEVICES); - devs = kmalloc_objs(devs, sbi->s_ndevs); - if (!devs) - return ERR_PTR(-ENOMEM); + if (!f2fs_is_multi_device(sbi)) { + devs[0] = sb->s_bdev; + return 1; + } + ndevs = sbi->s_ndevs; + if (WARN_ON_ONCE(ndevs > FSCRYPT_MAX_DEVICES)) + ndevs = FSCRYPT_MAX_DEVICES; - for (i = 0; i < sbi->s_ndevs; i++) + for (i = 0; i < ndevs; i++) devs[i] = FDEV(i).bdev; - num_devs = sbi->s_ndevs; - return devs; + return ndevs; } static const struct fscrypt_operations f2fs_cryptops = { diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 54712ec61ffb7c..f6b235cd72b45d 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -57,6 +57,9 @@ struct fscrypt_name { / Maximum value for the third parameter of fscrypt_operations.set_context(). / #define FSCRYPT_SET_CONTEXT_MAX_SIZE 40 +/ Maximum supported number of block devices per filesystem / +#define FSCRYPT_MAX_DEVICES 8 + #ifdef CONFIG_FS_ENCRYPTION / Crypto operations for filesystems / @@ -181,21 +184,20 @@ struct fscrypt_operations { bool (has_stable_inodes)(struct super_block sb); / - * Return an array of pointers to the block devices to which the - * filesystem may write encrypted file contents, NULL if the filesystem - * only has a single such block device, or an ERR_PTR() on error. + * Retrieve the list of block devices to which the filesystem may write + * encrypted file contents. * - * On successful non-NULL return, num_devs is set to the number of - devices in the returned array. The caller must free the returned - * array using kfree(). + * This writes the block_device pointers to @devs and returns the count + * (between 1 and FSCRYPT_MAX_DEVICES inclusively). * * If the filesystem can use multiple block devices (other than block * devices that aren't used for encrypted file contents, such as * external journal devices), and wants to support inline encryption, * then it must implement this function. Otherwise it's not needed. / - struct block_device (get_devices)(struct super_block sb, - unsigned int num_devs); + unsigned int (get_devices)( + struct super_block sb, + struct block_device devs[FSCRYPT_MAX_DEVICES]); }; int fscrypt_d_revalidate(struct inode dir, const struct qstr *name,
3/2	2026/07/19 06:11	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 4384 output: 36 thoughts: 294 Thoughts: Analyzing the Inline Crypt Patch Okay, so I'm looking at this patch that aims to optimize the `fscrypt_get_devices` function, specifically within `fs/crypto/inline_crypt.c` and `fs/f2fs/super.c`. Instead of dynamically allocating that array of block device pointers using `kmalloc_obj`, it's switching to a fixed-size, stack-allocated array: `struct block_device *devs[FSCRYPT_MAX_DEVICES]`. That's smart; it eliminates potential `ENOMEM` errors from allocation failures and, at a glance, should simplify the overall code flow, a good trade-off. The signature of `fscrypt_get_devices` will need to be updated, and the implementation in `fs/f2fs/super.c` has to change too, naturally. Crucially, this stack-allocated array will need to be propagated through other relevant functions: `fscrypt_select_encryption_impl`, `fscrypt_prepare_inline_crypt_key`, and `fscrypt_destroy_inline_crypt_key`. Functionally, this is a significant shift. We're altering how memory is allocated, trading the flexibility of the heap for the determinism of the stack. We're also removing the error handling related to `ENOMEM` since, theoretically, stack allocation can't fail (unless we exceed the stack size, but that's a different, rarer problem). This touches `fs/crypto/inline_crypt.c` and `fs/f2fs/super.c`, as expected. I need to confirm the conditions for the code path. I should pull up `fs/crypto/inline_crypt.c` in the kernel source and make sure the relevant configuration options (`CONFIG_FS_ENCRYPTION_INLINE_CRYPT` and `CONFIG_F2FS_FS`) are enabled. That will tell me when the code is actually reachable. This is a crucial first step; can't go through the code if the code itself is disabled.
4/2	2026/07/19 06:11	tool	grepper	0m Args: { "Expression": "CONFIG_FS_ENCRYPTION_INLINE_CRYPT", "PathPrefix": "fs/crypto/" } Results: { "Output": "fs/crypto/Makefile=13=fscrypto-$(CONFIG_BLOCK) += bio.o\nfs/crypto/Makefile:14:fscrypto-$(CONFIG_FS_ENCRYPTION_INLINE_CRYPT) += inline_crypt.o\n--\nfs/crypto/fscrypt_private.h=241=struct fscrypt_prepared_key {\nfs/crypto/fscrypt_private.h-242-\tstruct crypto_sync_skcipher tfm;\nfs/crypto/fscrypt_private.h:243:#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT\nfs/crypto/fscrypt_private.h-244-\tstruct blk_crypto_key blk_key;\n--\nfs/crypto/fscrypt_private.h=264=struct fscrypt_inode_info {\n--\nfs/crypto/fscrypt_private.h-271-\nfs/crypto/fscrypt_private.h:272:#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT\nfs/crypto/fscrypt_private.h-273-\t/\n--\nfs/crypto/fscrypt_private.h=410=void fscrypt_hkdf_expand(const struct hmac_sha512_key hkdf, u8 context,\n--\nfs/crypto/fscrypt_private.h-414-/* inline_crypt.c /\nfs/crypto/fscrypt_private.h:415:#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT\nfs/crypto/fscrypt_private.h-416-int fscrypt_select_encryption_impl(struct fscrypt_inode_info ci,\n--\nfs/crypto/fscrypt_private.h=442=fscrypt_is_key_prepared(const struct fscrypt_prepared_key prep_key,\n--\nfs/crypto/fscrypt_private.h-449-\nfs/crypto/fscrypt_private.h:450:#else / CONFIG_FS_ENCRYPTION_INLINE_CRYPT /\nfs/crypto/fscrypt_private.h-451-\n--\nfs/crypto/fscrypt_private.h=490=fscrypt_is_key_prepared(const struct fscrypt_prepared_key prep_key,\n--\nfs/crypto/fscrypt_private.h-494-}\nfs/crypto/fscrypt_private.h:495:#endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */\nfs/crypto/fscrypt_private.h-496-\n" }
5/2	2026/07/19 06:11	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 5805 output: 36 thoughts: 54 Thoughts: Okay, let's see, the core of this seems to revolve around filesystem encryption in F2FS. Specifically, I need to look at how it's implemented. Analyzing F2FS Encryption Configuration Right, so I know I need to be aware of `CONFIG_FS_ENCRYPTION_INLINE_CRYPT` and `CONFIG_F2FS_FS`. They're the critical configurations for this inline encryption feature within F2FS. Now, where would I expect to find the meat of this? Let's go straight to the source. Given the connection to F2FS and the mention of device setup, I’m betting `fs/f2fs/super.c` will hold the key, particularly focusing on how devices are acquired. I’ll look for `f2fs_get_devices` as a starting point. That should provide a good overview of the relevant initialization and device handling aspects regarding the feature.
6/2	2026/07/19 06:11	tool	grepper	0m Args: { "Expression": "f2fs_get_devices", "PathPrefix": "fs/f2fs/super.c" } Results: { "Output": "fs/f2fs/super.c=3752=static unsigned int\nfs/f2fs/super.c:3753:f2fs_get_devices(struct super_block sb,\nfs/f2fs/super.c-3754-\t\t struct block_device devs[FSCRYPT_MAX_DEVICES])\n--\nfs/f2fs/super.c=3775=static const struct fscrypt_operations f2fs_cryptops = {\n--\nfs/f2fs/super.c-3786-\t.has_stable_inodes\t= f2fs_has_stable_inodes,\nfs/f2fs/super.c:3787:\t.get_devices\t\t= f2fs_get_devices,\nfs/f2fs/super.c-3788-};\n" }
7/2	2026/07/19 06:11	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 6307 output: 36 thoughts: 25 Thoughts: Here's my thought process, summarized as you requested: Navigating the Filesystem Cryptography Code Okay, so I need to find where the `fscrypt_get_devices` function lives. Given the context, my initial hunch is that it's likely involved with inline encryption. Therefore, the most logical place to start digging is the `fs/crypto` directory. Within that, I'm pretty confident the `inline_crypt.c` file is where I'll find the device-related function. Let's head there and see what's what. That seems like a solid initial starting point.
8/2	2026/07/19 06:11	tool	grepper	0m Args: { "Expression": "fscrypt_get_devices", "PathPrefix": "fs/crypto/inline_crypt.c" } Results: { "Output": "fs/crypto/inline_crypt.c=25=static unsigned int\nfs/crypto/inline_crypt.c:26:fscrypt_get_devices(struct super_block sb,\nfs/crypto/inline_crypt.c-27-\t\t struct block_device devs[FSCRYPT_MAX_DEVICES])\n--\nfs/crypto/inline_crypt.c=85=int fscrypt_select_encryption_impl(struct fscrypt_inode_info ci,\n--\nfs/crypto/inline_crypt.c-129-\nfs/crypto/inline_crypt.c:130:\tnum_devs = fscrypt_get_devices(sb, devs);\nfs/crypto/inline_crypt.c-131-\tfor (i = 0; i \u003c num_devs; i++) {\n--\nfs/crypto/inline_crypt.c=143=int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key prep_key,\n--\nfs/crypto/inline_crypt.c-171-\t/* Start using blk-crypto on all the filesystem's block devices. /\nfs/crypto/inline_crypt.c:172:\tnum_devs = fscrypt_get_devices(sb, devs);\nfs/crypto/inline_crypt.c-173-\tfor (i = 0; i \u003c num_devs; i++) {\n--\nfs/crypto/inline_crypt.c=191=void fscrypt_destroy_inline_crypt_key(struct super_block sb,\n--\nfs/crypto/inline_crypt.c-205-\t */\nfs/crypto/inline_crypt.c:206:\tnum_devs = fscrypt_get_devices(sb, devs);\nfs/crypto/inline_crypt.c-207-\tfor (i = 0; i \u003c num_devs; i++)\n" }
9/2	2026/07/19 06:11	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 6976 output: 31 thoughts: 123 Thoughts: Fuzzing Focus: Key Functions and Configurations Okay, so I've been reviewing the recent changes, and it's clear we need to give some focused attention to specific functions in the file system encryption code. Specifically, I'm thinking about fuzzing `fscrypt_select_encryption_impl`, `fscrypt_prepare_inline_crypt_key`, `fscrypt_destroy_inline_crypt_key`, and `f2fs_get_devices`. These seem like the prime candidates for poking and prodding to see if we can find any hidden vulnerabilities or edge cases. Now, considering the configurations that are relevant here, we are looking at `FS_ENCRYPTION_INLINE_CRYPT`, `F2FS_FS`, and, of course, the general `FS_ENCRYPTION` configuration. It's crucial that we ensure proper coverage within the fuzzer. It's also worth a quick check to see if `FS_ENCRYPTION_INLINE_CRYPT` has any dependencies that could affect our fuzzing strategy. We don't want to miss anything.
10/2	2026/07/19 06:11	tool	grepper	0m Args: { "Expression": "config FS_ENCRYPTION_INLINE_CRYPT", "PathPrefix": "" } Results: { "Output": "fs/crypto/Kconfig=29=config FS_ENCRYPTION_ALGS\n--\nfs/crypto/Kconfig-35-\nfs/crypto/Kconfig:36:config FS_ENCRYPTION_INLINE_CRYPT\nfs/crypto/Kconfig-37-\tbool \"Enable fscrypt to use inline crypto\"\n" }
11/2	2026/07/19 06:11	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 7455 output: 33 thoughts: 18 Thoughts: Here's my take on the `fs/crypto/Kconfig` thought process: Diving into Filesystem Crypto Configuration Okay, let's get down to brass tacks. I'm thinking we need to delve into the `fs/crypto/Kconfig` file. I'm specifically aiming for around line 36. This suggests we're likely looking at some specific configuration options related to filesystem-level encryption within the Linux kernel. Given my expertise, I'm expecting to find details around enabling, disabling, and perhaps configuring various cryptographic algorithms, key management methods, or filesystem-specific features like fscrypt. My past experience tells me Kconfig files are the heart of kernel configuration, so this is where I would start to understand how a particular filesystem's encryption capabilities are controlled and presented to the end-user. I'm keen to see if this area has been updated recently, and if any security considerations are documented there.
12/2	2026/07/19 06:11	tool	read-file	0m Args: { "File": "fs/crypto/Kconfig", "FirstLine": 30, "LineCount": 20 } Results: { "Contents": " 30:\t\ttristate\n 31:\t\tselect CRYPTO_AES\n 32:\t\tselect CRYPTO_CBC\n 33:\t\tselect CRYPTO_CTS\n 34:\t\tselect CRYPTO_XTS\n 35:\t\n 36:\tconfig FS_ENCRYPTION_INLINE_CRYPT\n 37:\t\tbool \"Enable fscrypt to use inline crypto\"\n 38:\t\tdepends on FS_ENCRYPTION \u0026\u0026 BLK_INLINE_ENCRYPTION\n 39:\t\thelp\n 40:\t\t Enable fscrypt to use inline encryption hardware if available.\n" }
13/2	2026/07/19 06:11	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 7861 output: 30 thoughts: 48 Thoughts: Okay, here's my take on those thoughts, framed as my own mental processing: Dependencies and Block-Level Encryption Right, let's break this down. My initial observation is that `FS_ENCRYPTION_INLINE_CRYPT` relies on both `FS_ENCRYPTION` and `BLK_INLINE_ENCRYPTION`. That's a good starting point, and I need to keep that dependency tree in mind. Now, the logical next step is to drill down into `BLK_INLINE_ENCRYPTION`. I'll need to understand what it does to fully grasp the capabilities and implications of `FS_ENCRYPTION_INLINE_CRYPT`. What are its underlying mechanisms? Are there any specific hardware dependencies? What algorithms does it support? Knowing that will be key to understanding the full picture here.
14/2	2026/07/19 06:11	tool	grepper	0m Args: { "Expression": "config BLK_INLINE_ENCRYPTION", "PathPrefix": "" } Results: { "Output": "block/Kconfig=185=config BLK_SED_OPAL\n--\nblock/Kconfig-194-\nblock/Kconfig:195:config BLK_INLINE_ENCRYPTION\nblock/Kconfig-196-\tbool \"Enable inline encryption support in block layer\"\n--\nblock/Kconfig-201-\nblock/Kconfig:202:config BLK_INLINE_ENCRYPTION_FALLBACK\nblock/Kconfig-203-\tbool \"Enable crypto API fallback for blk-crypto\"\n" }
15/2	2026/07/19 06:11	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 8261 output: 33 thoughts: 101 Thoughts: Okay, here's my understanding, tailored for an expert audience, as a first-person account of the thought process: Enabling Inline Encryption for Performance and Functionality Right, let's get down to business. My immediate priority is to enable inline encryption capabilities within the file system stack. Specifically, I'm thinking about enabling three key options in the kernel configuration: `FS_ENCRYPTION_INLINE_CRYPT`, `BLK_INLINE_ENCRYPTION`, and `F2FS_FS`. The first two are, of course, critical for inline encryption and performance. And the latter enables the F2FS filesystem, which often benefits from these features. And of course we also need to enable just plain old `FS_ENCRYPTION`. Now, before we go any further, I need to verify a couple of critical function calls that are pivotal to the encryption flow. I'm focusing on ensuring `fscrypt_select_encryption_impl` and `fscrypt_prepare_inline_crypt_key` are actually reachable during runtime. It's a fundamental step to check for any dead code or configuration issues. I'm mentally tracing the call paths, and they should be called from the `fs/crypto/policy.c` and `fs/crypto/keysetup.c` files. This is where the core policy management and key setup logic reside, so it makes sense that these functions would be invoked from those code paths. I need to make sure the build and runtime configs are set up to actually allow them to be called.
16/2	2026/07/19 06:11	tool	grepper	0m Args: { "Expression": "fscrypt_select_encryption_impl", "PathPrefix": "fs/crypto/" } Results: { "Output": "fs/crypto/fscrypt_private.h=410=void fscrypt_hkdf_expand(const struct hmac_sha512_key hkdf, u8 context,\n--\nfs/crypto/fscrypt_private.h-415-#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT\nfs/crypto/fscrypt_private.h:416:int fscrypt_select_encryption_impl(struct fscrypt_inode_info ci,\nfs/crypto/fscrypt_private.h-417-\t\t\t\t bool is_hw_wrapped_key);\n--\nfs/crypto/fscrypt_private.h=442=fscrypt_is_key_prepared(const struct fscrypt_prepared_key prep_key,\n--\nfs/crypto/fscrypt_private.h-451-\nfs/crypto/fscrypt_private.h:452:static inline int fscrypt_select_encryption_impl(struct fscrypt_inode_info ci,\nfs/crypto/fscrypt_private.h-453-\t\t\t\t\t\t bool is_hw_wrapped_key)\n--\nfs/crypto/inline_crypt.c=64=static void fscrypt_log_blk_crypto_impl(struct fscrypt_mode mode,\n--\nfs/crypto/inline_crypt.c-84-/ Enable inline encryption for this file if supported. /\nfs/crypto/inline_crypt.c:85:int fscrypt_select_encryption_impl(struct fscrypt_inode_info ci,\nfs/crypto/inline_crypt.c-86-\t\t\t\t bool is_hw_wrapped_key)\n--\nfs/crypto/keysetup.c=482=static int setup_file_encryption_key(struct fscrypt_inode_info *ci,\n--\nfs/crypto/keysetup.c-517-\nfs/crypto/keysetup.c:518:\t\terr = fscrypt_select_encryption_impl(ci, false);\nfs/crypto/keysetup.c-519-\t\tif (err)\n--\nfs/crypto/keysetup.c-542-\nfs/crypto/keysetup.c:543:\terr = fscrypt_select_encryption_impl(ci, mk-\u003emk_secret.is_hw_wrapped);\nfs/crypto/keysetup.c-544-\tif (err)\n" }
17/2	2026/07/19 06:11	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 9326 output: 183 thoughts: 442 Thoughts: Analyzing the Inline Encryption Patch Okay, so I've got a patch here that's changing the allocation strategy for block device arrays, specifically within the context of inline encryption, and how it's handled in `fscrypt_get_devices` and `f2fs_get_devices`. Instead of dynamic heap allocation (`kmalloc_obj`), it looks like they're moving to a fixed-size, stack-allocated array. This clearly impacts the setup and teardown paths for inline encryption. My immediate concern? This screams fuzzing opportunity. We need to zero in on these inline encryption paths to ensure there's no stack corruption or out-of-bounds access happening, especially considering F2FS and the potential for multiple devices. Let me make sure I have the function names right. Checks... Yep, `f2fs_get_devices` is indeed the correct name. Now, about `fscrypt_get_devices`... Double checks... Ah, it's static! That means it might be inlined, which makes it less useful as a direct fuzzing target. We're better off focusing on the callers: `fscrypt_select_encryption_impl`, `fscrypt_prepare_inline_crypt_key`, and `fscrypt_destroy_inline_crypt_key`. Those are definitely the places to start. Now, `f2fs_get_devices` is also static within the F2FS code, but it's assigned to a function pointer, `f2fs_cryptops.get_devices`. That means it's not likely to be inlined, and we should definitely keep it on the radar as a focus symbol. Okay, I think I have a solid understanding of the implications and a clear fuzzing strategy. Time to call `set-results`.
18/2	2026/07/19 06:12	tool	set-results	0m Args: { "EnableConfigs": [ "FS_ENCRYPTION_INLINE_CRYPT", "BLK_INLINE_ENCRYPTION", "F2FS_FS" ], "FocusSymbols": [ "fscrypt_select_encryption_impl", "fscrypt_prepare_inline_crypt_key", "fscrypt_destroy_inline_crypt_key", "f2fs_get_devices" ], "Reasoning": "The patch changes how block device arrays are allocated in fscrypt and f2fs, moving from dynamic heap allocation to a fixed-size stack array. This affects inline encryption setup and teardown paths. Fuzzing should focus on these paths to ensure no stack corruption or out-of-bounds access occurs, especially with multiple devices in f2fs.", "WorthFuzzing": true } Results: { "EnableConfigs": [ "FS_ENCRYPTION_INLINE_CRYPT", "BLK_INLINE_ENCRYPTION", "F2FS_FS" ], "FocusSymbols": [ "fscrypt_select_encryption_impl", "fscrypt_prepare_inline_crypt_key", "fscrypt_destroy_inline_crypt_key", "f2fs_get_devices" ], "Reasoning": "The patch changes how block device arrays are allocated in fscrypt and f2fs, moving from dynamic heap allocation to a fixed-size stack array. This affects inline encryption setup and teardown paths. Fuzzing should focus on these paths to ensure no stack corruption or out-of-bounds access occurs, especially with multiple devices in f2fs.", "WorthFuzzing": true }

{
  "EnableConfigs": [
    "FS_ENCRYPTION_INLINE_CRYPT",
    "BLK_INLINE_ENCRYPTION",
    "F2FS_FS"
  ],
  "FocusSymbols": [
    "fscrypt_select_encryption_impl",
    "fscrypt_prepare_inline_crypt_key",
    "fscrypt_destroy_inline_crypt_key",
    "f2fs_get_devices"
  ],
  "Reasoning": "The patch changes how block device arrays are allocated in fscrypt and f2fs, moving from dynamic heap allocation to a fixed-size stack array. This affects inline encryption setup and teardown paths. Fuzzing should focus on these paths to ensure no stack corruption or out-of-bounds access occurs, especially with multiple devices in f2fs.",
  "WorthFuzzing": true
}

{
  "PatchDiff": "commit 04976aa1df55caef35adea06fbf33a89d2932359\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Sun Jul 19 06:11:24 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c\nindex 47324062fee514..66b9c9150fed66 100644\n--- a/fs/crypto/inline_crypt.c\n+++ b/fs/crypto/inline_crypt.c\n@@ -22,22 +22,14 @@\n \n #include \"fscrypt_private.h\"\n \n-static struct block_device **fscrypt_get_devices(struct super_block *sb,\n-\t\t\t\t\t\t unsigned int *num_devs)\n+static unsigned int\n+fscrypt_get_devices(struct super_block *sb,\n+\t\t    struct block_device *devs[FSCRYPT_MAX_DEVICES])\n {\n-\tstruct block_device **devs;\n-\n-\tif (sb-\u003es_cop-\u003eget_devices) {\n-\t\tdevs = sb-\u003es_cop-\u003eget_devices(sb, num_devs);\n-\t\tif (devs)\n-\t\t\treturn devs;\n-\t}\n-\tdevs = kmalloc_obj(*devs);\n-\tif (!devs)\n-\t\treturn ERR_PTR(-ENOMEM);\n+\tif (sb-\u003es_cop-\u003eget_devices)\n+\t\treturn sb-\u003es_cop-\u003eget_devices(sb, devs);\n \tdevs[0] = sb-\u003es_bdev;\n-\t*num_devs = 1;\n-\treturn devs;\n+\treturn 1;\n }\n \n static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_inode_info *ci)\n@@ -96,7 +88,7 @@ int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci,\n \tconst struct inode *inode = ci-\u003eci_inode;\n \tstruct super_block *sb = inode-\u003ei_sb;\n \tstruct blk_crypto_config crypto_cfg;\n-\tstruct block_device **devs;\n+\tstruct block_device *devs[FSCRYPT_MAX_DEVICES];\n \tunsigned int num_devs;\n \tunsigned int i;\n \n@@ -135,20 +127,15 @@ int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci,\n \tcrypto_cfg.key_type = is_hw_wrapped_key ?\n \t\tBLK_CRYPTO_KEY_TYPE_HW_WRAPPED : BLK_CRYPTO_KEY_TYPE_RAW;\n \n-\tdevs = fscrypt_get_devices(sb, \u0026num_devs);\n-\tif (IS_ERR(devs))\n-\t\treturn PTR_ERR(devs);\n-\n+\tnum_devs = fscrypt_get_devices(sb, devs);\n \tfor (i = 0; i \u003c num_devs; i++) {\n \t\tif (!blk_crypto_config_supported(devs[i], \u0026crypto_cfg))\n-\t\t\tgoto out_free_devs;\n+\t\t\treturn 0;\n \t}\n \n \tfscrypt_log_blk_crypto_impl(ci-\u003eci_mode, devs, num_devs, \u0026crypto_cfg);\n \n \tci-\u003eci_inlinecrypt = true;\n-out_free_devs:\n-\tkfree(devs);\n \n \treturn 0;\n }\n@@ -164,7 +151,7 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,\n \tenum blk_crypto_key_type key_type = is_hw_wrapped ?\n \t\tBLK_CRYPTO_KEY_TYPE_HW_WRAPPED : BLK_CRYPTO_KEY_TYPE_RAW;\n \tstruct blk_crypto_key *blk_key;\n-\tstruct block_device **devs;\n+\tstruct block_device *devs[FSCRYPT_MAX_DEVICES];\n \tunsigned int num_devs;\n \tunsigned int i;\n \tint err;\n@@ -182,17 +169,12 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,\n \t}\n \n \t/* Start using blk-crypto on all the filesystem's block devices. */\n-\tdevs = fscrypt_get_devices(sb, \u0026num_devs);\n-\tif (IS_ERR(devs)) {\n-\t\terr = PTR_ERR(devs);\n-\t\tgoto fail;\n-\t}\n+\tnum_devs = fscrypt_get_devices(sb, devs);\n \tfor (i = 0; i \u003c num_devs; i++) {\n \t\terr = blk_crypto_start_using_key(devs[i], blk_key);\n \t\tif (err)\n \t\t\tbreak;\n \t}\n-\tkfree(devs);\n \tif (err) {\n \t\tfscrypt_err(inode, \"error %d starting to use blk-crypto\", err);\n \t\tgoto fail;\n@@ -210,20 +192,21 @@ void fscrypt_destroy_inline_crypt_key(struct super_block *sb,\n \t\t\t\t      struct fscrypt_prepared_key *prep_key)\n {\n \tstruct blk_crypto_key *blk_key = prep_key-\u003eblk_key;\n-\tstruct block_device **devs;\n+\tstruct block_device *devs[FSCRYPT_MAX_DEVICES];\n \tunsigned int num_devs;\n \tunsigned int i;\n \n \tif (!blk_key)\n \t\treturn;\n \n-\t/* Evict the key from all the filesystem's block devices. */\n-\tdevs = fscrypt_get_devices(sb, \u0026num_devs);\n-\tif (!IS_ERR(devs)) {\n-\t\tfor (i = 0; i \u003c num_devs; i++)\n-\t\t\tblk_crypto_evict_key(devs[i], blk_key);\n-\t\tkfree(devs);\n-\t}\n+\t/*\n+\t * Evict the key from all the filesystem's block devices.\n+\t * This *must* be done before the key is freed.\n+\t */\n+\tnum_devs = fscrypt_get_devices(sb, devs);\n+\tfor (i = 0; i \u003c num_devs; i++)\n+\t\tblk_crypto_evict_key(devs[i], blk_key);\n+\n \tkfree_sensitive(blk_key);\n }\n \ndiff --git a/fs/f2fs/super.c b/fs/f2fs/super.c\nindex 2b8d964111562a..9760e4efeffeca 100644\n--- a/fs/f2fs/super.c\n+++ b/fs/f2fs/super.c\n@@ -3749,24 +3749,27 @@ static bool f2fs_has_stable_inodes(struct super_block *sb)\n \treturn true;\n }\n \n-static struct block_device **f2fs_get_devices(struct super_block *sb,\n-\t\t\t\t\t      unsigned int *num_devs)\n+static unsigned int\n+f2fs_get_devices(struct super_block *sb,\n+\t\t struct block_device *devs[FSCRYPT_MAX_DEVICES])\n {\n \tstruct f2fs_sb_info *sbi = F2FS_SB(sb);\n-\tstruct block_device **devs;\n+\tint ndevs;\n \tint i;\n \n-\tif (!f2fs_is_multi_device(sbi))\n-\t\treturn NULL;\n+\tstatic_assert(MAX_DEVICES \u003c= FSCRYPT_MAX_DEVICES);\n \n-\tdevs = kmalloc_objs(*devs, sbi-\u003es_ndevs);\n-\tif (!devs)\n-\t\treturn ERR_PTR(-ENOMEM);\n+\tif (!f2fs_is_multi_device(sbi)) {\n+\t\tdevs[0] = sb-\u003es_bdev;\n+\t\treturn 1;\n+\t}\n+\tndevs = sbi-\u003es_ndevs;\n+\tif (WARN_ON_ONCE(ndevs \u003e FSCRYPT_MAX_DEVICES))\n+\t\tndevs = FSCRYPT_MAX_DEVICES;\n \n-\tfor (i = 0; i \u003c sbi-\u003es_ndevs; i++)\n+\tfor (i = 0; i \u003c ndevs; i++)\n \t\tdevs[i] = FDEV(i).bdev;\n-\t*num_devs = sbi-\u003es_ndevs;\n-\treturn devs;\n+\treturn ndevs;\n }\n \n static const struct fscrypt_operations f2fs_cryptops = {\ndiff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h\nindex 54712ec61ffb7c..f6b235cd72b45d 100644\n--- a/include/linux/fscrypt.h\n+++ b/include/linux/fscrypt.h\n@@ -57,6 +57,9 @@ struct fscrypt_name {\n /* Maximum value for the third parameter of fscrypt_operations.set_context(). */\n #define FSCRYPT_SET_CONTEXT_MAX_SIZE\t40\n \n+/* Maximum supported number of block devices per filesystem */\n+#define FSCRYPT_MAX_DEVICES\t8\n+\n #ifdef CONFIG_FS_ENCRYPTION\n \n /* Crypto operations for filesystems */\n@@ -181,21 +184,20 @@ struct fscrypt_operations {\n \tbool (*has_stable_inodes)(struct super_block *sb);\n \n \t/*\n-\t * Return an array of pointers to the block devices to which the\n-\t * filesystem may write encrypted file contents, NULL if the filesystem\n-\t * only has a single such block device, or an ERR_PTR() on error.\n+\t * Retrieve the list of block devices to which the filesystem may write\n+\t * encrypted file contents.\n \t *\n-\t * On successful non-NULL return, *num_devs is set to the number of\n-\t * devices in the returned array.  The caller must free the returned\n-\t * array using kfree().\n+\t * This writes the block_device pointers to @devs and returns the count\n+\t * (between 1 and FSCRYPT_MAX_DEVICES inclusively).\n \t *\n \t * If the filesystem can use multiple block devices (other than block\n \t * devices that aren't used for encrypted file contents, such as\n \t * external journal devices), and wants to support inline encryption,\n \t * then it must implement this function.  Otherwise it's not needed.\n \t */\n-\tstruct block_device **(*get_devices)(struct super_block *sb,\n-\t\t\t\t\t     unsigned int *num_devs);\n+\tunsigned int (*get_devices)(\n+\t\tstruct super_block *sb,\n+\t\tstruct block_device *devs[FSCRYPT_MAX_DEVICES]);\n };\n \n int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name,\n"
}

gemini-3.1-pro-preview

{
  "EnableConfigs": [
    "FS_ENCRYPTION_INLINE_CRYPT",
    "BLK_INLINE_ENCRYPTION",
    "F2FS_FS"
  ],
  "FocusSymbols": [
    "fscrypt_select_encryption_impl",
    "fscrypt_prepare_inline_crypt_key",
    "fscrypt_destroy_inline_crypt_key",
    "f2fs_get_devices"
  ],
  "Reasoning": "The patch changes how block device arrays are allocated in fscrypt and f2fs, moving from dynamic heap allocation to a fixed-size stack array. This affects inline encryption setup and teardown paths. Fuzzing should focus on these paths to ensure no stack corruption or out-of-bounds access occurs, especially with multiple devices in f2fs.",
  "WorthFuzzing": true
}

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).

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.
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.
   Do not list too generic configs (we already have them enabled). Only list those that
   specifically cover the modified code. 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.

For your convenience, here is the diff of the changes:
commit 04976aa1df55caef35adea06fbf33a89d2932359
Author: syz-cluster <triage@syzkaller.com>
Date:   Sun Jul 19 06:11:24 2026 +0000

    syz-cluster: applied patch under review

diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c
index 47324062fee514..66b9c9150fed66 100644
--- a/fs/crypto/inline_crypt.c
+++ b/fs/crypto/inline_crypt.c
@@ -22,22 +22,14 @@
 
 #include "fscrypt_private.h"
 
-static struct block_device **fscrypt_get_devices(struct super_block *sb,
-						 unsigned int *num_devs)
+static unsigned int
+fscrypt_get_devices(struct super_block *sb,
+		    struct block_device *devs[FSCRYPT_MAX_DEVICES])
 {
-	struct block_device **devs;
-
-	if (sb->s_cop->get_devices) {
-		devs = sb->s_cop->get_devices(sb, num_devs);
-		if (devs)
-			return devs;
-	}
-	devs = kmalloc_obj(*devs);
-	if (!devs)
-		return ERR_PTR(-ENOMEM);
+	if (sb->s_cop->get_devices)
+		return sb->s_cop->get_devices(sb, devs);
 	devs[0] = sb->s_bdev;
-	*num_devs = 1;
-	return devs;
+	return 1;
 }
 
 static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_inode_info *ci)
@@ -96,7 +88,7 @@ int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci,
 	const struct inode *inode = ci->ci_inode;
 	struct super_block *sb = inode->i_sb;
 	struct blk_crypto_config crypto_cfg;
-	struct block_device **devs;
+	struct block_device *devs[FSCRYPT_MAX_DEVICES];
 	unsigned int num_devs;
 	unsigned int i;
 
@@ -135,20 +127,15 @@ int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci,
 	crypto_cfg.key_type = is_hw_wrapped_key ?
 		BLK_CRYPTO_KEY_TYPE_HW_WRAPPED : BLK_CRYPTO_KEY_TYPE_RAW;
 
-	devs = fscrypt_get_devices(sb, &num_devs);
-	if (IS_ERR(devs))
-		return PTR_ERR(devs);
-
+	num_devs = fscrypt_get_devices(sb, devs);
 	for (i = 0; i < num_devs; i++) {
 		if (!blk_crypto_config_supported(devs[i], &crypto_cfg))
-			goto out_free_devs;
+			return 0;
 	}
 
 	fscrypt_log_blk_crypto_impl(ci->ci_mode, devs, num_devs, &crypto_cfg);
 
 	ci->ci_inlinecrypt = true;
-out_free_devs:
-	kfree(devs);
 
 	return 0;
 }
@@ -164,7 +151,7 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
 	enum blk_crypto_key_type key_type = is_hw_wrapped ?
 		BLK_CRYPTO_KEY_TYPE_HW_WRAPPED : BLK_CRYPTO_KEY_TYPE_RAW;
 	struct blk_crypto_key *blk_key;
-	struct block_device **devs;
+	struct block_device *devs[FSCRYPT_MAX_DEVICES];
 	unsigned int num_devs;
 	unsigned int i;
 	int err;
@@ -182,17 +169,12 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
 	}
 
 	/* Start using blk-crypto on all the filesystem's block devices. */
-	devs = fscrypt_get_devices(sb, &num_devs);
-	if (IS_ERR(devs)) {
-		err = PTR_ERR(devs);
-		goto fail;
-	}
+	num_devs = fscrypt_get_devices(sb, devs);
 	for (i = 0; i < num_devs; i++) {
 		err = blk_crypto_start_using_key(devs[i], blk_key);
 		if (err)
 			break;
 	}
-	kfree(devs);
 	if (err) {
 		fscrypt_err(inode, "error %d starting to use blk-crypto", err);
 		goto fail;
@@ -210,20 +192,21 @@ void fscrypt_destroy_inline_crypt_key(struct super_block *sb,
 				      struct fscrypt_prepared_key *prep_key)
 {
 	struct blk_crypto_key *blk_key = prep_key->blk_key;
-	struct block_device **devs;
+	struct block_device *devs[FSCRYPT_MAX_DEVICES];
 	unsigned int num_devs;
 	unsigned int i;
 
 	if (!blk_key)
 		return;
 
-	/* Evict the key from all the filesystem's block devices. */
-	devs = fscrypt_get_devices(sb, &num_devs);
-	if (!IS_ERR(devs)) {
-		for (i = 0; i < num_devs; i++)
-			blk_crypto_evict_key(devs[i], blk_key);
-		kfree(devs);
-	}
+	/*
+	 * Evict the key from all the filesystem's block devices.
+	 * This *must* be done before the key is freed.
+	 */
+	num_devs = fscrypt_get_devices(sb, devs);
+	for (i = 0; i < num_devs; i++)
+		blk_crypto_evict_key(devs[i], blk_key);
+
 	kfree_sensitive(blk_key);
 }
 
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 2b8d964111562a..9760e4efeffeca 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3749,24 +3749,27 @@ static bool f2fs_has_stable_inodes(struct super_block *sb)
 	return true;
 }
 
-static struct block_device **f2fs_get_devices(struct super_block *sb,
-					      unsigned int *num_devs)
+static unsigned int
+f2fs_get_devices(struct super_block *sb,
+		 struct block_device *devs[FSCRYPT_MAX_DEVICES])
 {
 	struct f2fs_sb_info *sbi = F2FS_SB(sb);
-	struct block_device **devs;
+	int ndevs;
 	int i;
 
-	if (!f2fs_is_multi_device(sbi))
-		return NULL;
+	static_assert(MAX_DEVICES <= FSCRYPT_MAX_DEVICES);
 
-	devs = kmalloc_objs(*devs, sbi->s_ndevs);
-	if (!devs)
-		return ERR_PTR(-ENOMEM);
+	if (!f2fs_is_multi_device(sbi)) {
+		devs[0] = sb->s_bdev;
+		return 1;
+	}
+	ndevs = sbi->s_ndevs;
+	if (WARN_ON_ONCE(ndevs > FSCRYPT_MAX_DEVICES))
+		ndevs = FSCRYPT_MAX_DEVICES;
 
-	for (i = 0; i < sbi->s_ndevs; i++)
+	for (i = 0; i < ndevs; i++)
 		devs[i] = FDEV(i).bdev;
-	*num_devs = sbi->s_ndevs;
-	return devs;
+	return ndevs;
 }
 
 static const struct fscrypt_operations f2fs_cryptops = {
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index 54712ec61ffb7c..f6b235cd72b45d 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -57,6 +57,9 @@ struct fscrypt_name {
 /* Maximum value for the third parameter of fscrypt_operations.set_context(). */
 #define FSCRYPT_SET_CONTEXT_MAX_SIZE	40
 
+/* Maximum supported number of block devices per filesystem */
+#define FSCRYPT_MAX_DEVICES	8
+
 #ifdef CONFIG_FS_ENCRYPTION
 
 /* Crypto operations for filesystems */
@@ -181,21 +184,20 @@ struct fscrypt_operations {
 	bool (*has_stable_inodes)(struct super_block *sb);
 
 	/*
-	 * Return an array of pointers to the block devices to which the
-	 * filesystem may write encrypted file contents, NULL if the filesystem
-	 * only has a single such block device, or an ERR_PTR() on error.
+	 * Retrieve the list of block devices to which the filesystem may write
+	 * encrypted file contents.
 	 *
-	 * On successful non-NULL return, *num_devs is set to the number of
-	 * devices in the returned array.  The caller must free the returned
-	 * array using kfree().
+	 * This writes the block_device pointers to @devs and returns the count
+	 * (between 1 and FSCRYPT_MAX_DEVICES inclusively).
 	 *
 	 * If the filesystem can use multiple block devices (other than block
 	 * devices that aren't used for encrypted file contents, such as
 	 * external journal devices), and wants to support inline encryption,
 	 * then it must implement this function.  Otherwise it's not needed.
 	 */
-	struct block_device **(*get_devices)(struct super_block *sb,
-					     unsigned int *num_devs);
+	unsigned int (*get_devices)(
+		struct super_block *sb,
+		struct block_device *devs[FSCRYPT_MAX_DEVICES]);
 };
 
 int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name,

gemini-3.1-pro-preview

							input: 4384
							output: 36
							thoughts: 294

**Analyzing the Inline Crypt Patch**

Okay, so I'm looking at this patch that aims to optimize the `fscrypt_get_devices` function, specifically within `fs/crypto/inline_crypt.c` and `fs/f2fs/super.c`. Instead of dynamically allocating that array of block device pointers using `kmalloc_obj`, it's switching to a fixed-size, stack-allocated array: `struct block_device *devs[FSCRYPT_MAX_DEVICES]`. That's smart; it eliminates potential `ENOMEM` errors from allocation failures and, at a glance, should simplify the overall code flow, a good trade-off.

The signature of `fscrypt_get_devices` will need to be updated, and the implementation in `fs/f2fs/super.c` has to change too, naturally. Crucially, this stack-allocated array will need to be propagated through other relevant functions: `fscrypt_select_encryption_impl`, `fscrypt_prepare_inline_crypt_key`, and `fscrypt_destroy_inline_crypt_key`.

Functionally, this is a significant shift. We're altering how memory is allocated, trading the flexibility of the heap for the determinism of the stack. We're also removing the error handling related to `ENOMEM` since, theoretically, stack allocation can't fail (unless we exceed the stack size, but that's a different, rarer problem). This touches `fs/crypto/inline_crypt.c` and `fs/f2fs/super.c`, as expected.

I need to confirm the conditions for the code path. I should pull up `fs/crypto/inline_crypt.c` in the kernel source and make sure the relevant configuration options (`CONFIG_FS_ENCRYPTION_INLINE_CRYPT` and `CONFIG_F2FS_FS`) are enabled. That will tell me when the code is actually reachable. This is a crucial first step; can't go through the code if the code itself is disabled.

{
  "Expression": "CONFIG_FS_ENCRYPTION_INLINE_CRYPT",
  "PathPrefix": "fs/crypto/"
}

{
  "Output": "fs/crypto/Makefile=13=fscrypto-$(CONFIG_BLOCK) += bio.o\nfs/crypto/Makefile:14:fscrypto-$(CONFIG_FS_ENCRYPTION_INLINE_CRYPT) += inline_crypt.o\n--\nfs/crypto/fscrypt_private.h=241=struct fscrypt_prepared_key {\nfs/crypto/fscrypt_private.h-242-\tstruct crypto_sync_skcipher *tfm;\nfs/crypto/fscrypt_private.h:243:#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT\nfs/crypto/fscrypt_private.h-244-\tstruct blk_crypto_key *blk_key;\n--\nfs/crypto/fscrypt_private.h=264=struct fscrypt_inode_info {\n--\nfs/crypto/fscrypt_private.h-271-\nfs/crypto/fscrypt_private.h:272:#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT\nfs/crypto/fscrypt_private.h-273-\t/*\n--\nfs/crypto/fscrypt_private.h=410=void fscrypt_hkdf_expand(const struct hmac_sha512_key *hkdf, u8 context,\n--\nfs/crypto/fscrypt_private.h-414-/* inline_crypt.c */\nfs/crypto/fscrypt_private.h:415:#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT\nfs/crypto/fscrypt_private.h-416-int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci,\n--\nfs/crypto/fscrypt_private.h=442=fscrypt_is_key_prepared(const struct fscrypt_prepared_key *prep_key,\n--\nfs/crypto/fscrypt_private.h-449-\nfs/crypto/fscrypt_private.h:450:#else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */\nfs/crypto/fscrypt_private.h-451-\n--\nfs/crypto/fscrypt_private.h=490=fscrypt_is_key_prepared(const struct fscrypt_prepared_key *prep_key,\n--\nfs/crypto/fscrypt_private.h-494-}\nfs/crypto/fscrypt_private.h:495:#endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */\nfs/crypto/fscrypt_private.h-496-\n"
}

gemini-3.1-pro-preview

							input: 5805
							output: 36
							thoughts: 54

Okay, let's see, the core of this seems to revolve around filesystem encryption in F2FS. Specifically, I need to look at how it's implemented.

**Analyzing F2FS Encryption Configuration**

Right, so I know I need to be aware of `CONFIG_FS_ENCRYPTION_INLINE_CRYPT` and `CONFIG_F2FS_FS`. They're the critical configurations for this inline encryption feature within F2FS. Now, where would I expect to find the meat of this? Let's go straight to the source. Given the connection to F2FS and the mention of device setup, I’m betting `fs/f2fs/super.c` will hold the key, particularly focusing on how devices are acquired. I’ll look for `f2fs_get_devices` as a starting point. That should provide a good overview of the relevant initialization and device handling aspects regarding the feature.

{
  "Expression": "f2fs_get_devices",
  "PathPrefix": "fs/f2fs/super.c"
}

{
  "Output": "fs/f2fs/super.c=3752=static unsigned int\nfs/f2fs/super.c:3753:f2fs_get_devices(struct super_block *sb,\nfs/f2fs/super.c-3754-\t\t struct block_device *devs[FSCRYPT_MAX_DEVICES])\n--\nfs/f2fs/super.c=3775=static const struct fscrypt_operations f2fs_cryptops = {\n--\nfs/f2fs/super.c-3786-\t.has_stable_inodes\t= f2fs_has_stable_inodes,\nfs/f2fs/super.c:3787:\t.get_devices\t\t= f2fs_get_devices,\nfs/f2fs/super.c-3788-};\n"
}

gemini-3.1-pro-preview

							input: 6307
							output: 36
							thoughts: 25

Here's my thought process, summarized as you requested:

**Navigating the Filesystem Cryptography Code**

Okay, so I need to find where the `fscrypt_get_devices` function lives. Given the context, my initial hunch is that it's likely involved with inline encryption. Therefore, the most logical place to start digging is the `fs/crypto` directory. Within that, I'm pretty confident the `inline_crypt.c` file is where I'll find the device-related function. Let's head there and see what's what. That seems like a solid initial starting point.

{
  "Expression": "fscrypt_get_devices",
  "PathPrefix": "fs/crypto/inline_crypt.c"
}

{
  "Output": "fs/crypto/inline_crypt.c=25=static unsigned int\nfs/crypto/inline_crypt.c:26:fscrypt_get_devices(struct super_block *sb,\nfs/crypto/inline_crypt.c-27-\t\t    struct block_device *devs[FSCRYPT_MAX_DEVICES])\n--\nfs/crypto/inline_crypt.c=85=int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci,\n--\nfs/crypto/inline_crypt.c-129-\nfs/crypto/inline_crypt.c:130:\tnum_devs = fscrypt_get_devices(sb, devs);\nfs/crypto/inline_crypt.c-131-\tfor (i = 0; i \u003c num_devs; i++) {\n--\nfs/crypto/inline_crypt.c=143=int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,\n--\nfs/crypto/inline_crypt.c-171-\t/* Start using blk-crypto on all the filesystem's block devices. */\nfs/crypto/inline_crypt.c:172:\tnum_devs = fscrypt_get_devices(sb, devs);\nfs/crypto/inline_crypt.c-173-\tfor (i = 0; i \u003c num_devs; i++) {\n--\nfs/crypto/inline_crypt.c=191=void fscrypt_destroy_inline_crypt_key(struct super_block *sb,\n--\nfs/crypto/inline_crypt.c-205-\t */\nfs/crypto/inline_crypt.c:206:\tnum_devs = fscrypt_get_devices(sb, devs);\nfs/crypto/inline_crypt.c-207-\tfor (i = 0; i \u003c num_devs; i++)\n"
}

gemini-3.1-pro-preview

							input: 6976
							output: 31
							thoughts: 123

**Fuzzing Focus: Key Functions and Configurations**

Okay, so I've been reviewing the recent changes, and it's clear we need to give some focused attention to specific functions in the file system encryption code. Specifically, I'm thinking about fuzzing `fscrypt_select_encryption_impl`, `fscrypt_prepare_inline_crypt_key`, `fscrypt_destroy_inline_crypt_key`, and `f2fs_get_devices`. These seem like the prime candidates for poking and prodding to see if we can find any hidden vulnerabilities or edge cases.

Now, considering the configurations that are relevant here, we are looking at `FS_ENCRYPTION_INLINE_CRYPT`, `F2FS_FS`, and, of course, the general `FS_ENCRYPTION` configuration. It's crucial that we ensure proper coverage within the fuzzer. It's also worth a quick check to see if `FS_ENCRYPTION_INLINE_CRYPT` has any dependencies that could affect our fuzzing strategy. We don't want to miss anything.

{
  "Expression": "config FS_ENCRYPTION_INLINE_CRYPT",
  "PathPrefix": ""
}

{
  "Output": "fs/crypto/Kconfig=29=config FS_ENCRYPTION_ALGS\n--\nfs/crypto/Kconfig-35-\nfs/crypto/Kconfig:36:config FS_ENCRYPTION_INLINE_CRYPT\nfs/crypto/Kconfig-37-\tbool \"Enable fscrypt to use inline crypto\"\n"
}

gemini-3.1-pro-preview

							input: 7455
							output: 33
							thoughts: 18

Here's my take on the `fs/crypto/Kconfig` thought process:

**Diving into Filesystem Crypto Configuration**

Okay, let's get down to brass tacks. I'm thinking we need to delve into the `fs/crypto/Kconfig` file. I'm specifically aiming for around line 36. This suggests we're likely looking at some specific configuration options related to filesystem-level encryption within the Linux kernel. Given my expertise, I'm expecting to find details around enabling, disabling, and perhaps configuring various cryptographic algorithms, key management methods, or filesystem-specific features like fscrypt. My past experience tells me Kconfig files are the heart of kernel configuration, so this is where I would start to understand how a particular filesystem's encryption capabilities are controlled and presented to the end-user. I'm keen to see if this area has been updated recently, and if any security considerations are documented there.

{
  "File": "fs/crypto/Kconfig",
  "FirstLine": 30,
  "LineCount": 20
}

{
  "Contents": "  30:\t\ttristate\n  31:\t\tselect CRYPTO_AES\n  32:\t\tselect CRYPTO_CBC\n  33:\t\tselect CRYPTO_CTS\n  34:\t\tselect CRYPTO_XTS\n  35:\t\n  36:\tconfig FS_ENCRYPTION_INLINE_CRYPT\n  37:\t\tbool \"Enable fscrypt to use inline crypto\"\n  38:\t\tdepends on FS_ENCRYPTION \u0026\u0026 BLK_INLINE_ENCRYPTION\n  39:\t\thelp\n  40:\t\t  Enable fscrypt to use inline encryption hardware if available.\n"
}

gemini-3.1-pro-preview

							input: 7861
							output: 30
							thoughts: 48

Okay, here's my take on those thoughts, framed as my own mental processing:

**Dependencies and Block-Level Encryption**

Right, let's break this down. My initial observation is that `FS_ENCRYPTION_INLINE_CRYPT` *relies* on both `FS_ENCRYPTION` and `BLK_INLINE_ENCRYPTION`. That's a good starting point, and I need to keep that dependency tree in mind. Now, the logical next step is to drill down into `BLK_INLINE_ENCRYPTION`. I'll need to understand what it *does* to fully grasp the capabilities and implications of `FS_ENCRYPTION_INLINE_CRYPT`. What are its underlying mechanisms? Are there any specific hardware dependencies? What algorithms does it support? Knowing that will be key to understanding the full picture here.

{
  "Expression": "config BLK_INLINE_ENCRYPTION",
  "PathPrefix": ""
}

{
  "Output": "block/Kconfig=185=config BLK_SED_OPAL\n--\nblock/Kconfig-194-\nblock/Kconfig:195:config BLK_INLINE_ENCRYPTION\nblock/Kconfig-196-\tbool \"Enable inline encryption support in block layer\"\n--\nblock/Kconfig-201-\nblock/Kconfig:202:config BLK_INLINE_ENCRYPTION_FALLBACK\nblock/Kconfig-203-\tbool \"Enable crypto API fallback for blk-crypto\"\n"
}

gemini-3.1-pro-preview

							input: 8261
							output: 33
							thoughts: 101

Okay, here's my understanding, tailored for an expert audience, as a first-person account of the thought process:

**Enabling Inline Encryption for Performance and Functionality**

Right, let's get down to business. My immediate priority is to enable inline encryption capabilities within the file system stack. Specifically, I'm thinking about enabling three key options in the kernel configuration: `FS_ENCRYPTION_INLINE_CRYPT`, `BLK_INLINE_ENCRYPTION`, and `F2FS_FS`. The first two are, of course, critical for inline encryption and performance. And the latter enables the F2FS filesystem, which often benefits from these features. And of course we also need to enable just plain old `FS_ENCRYPTION`.

Now, before we go any further, I need to verify a couple of critical function calls that are pivotal to the encryption flow. I'm focusing on ensuring `fscrypt_select_encryption_impl` and `fscrypt_prepare_inline_crypt_key` are actually reachable during runtime. It's a fundamental step to check for any dead code or configuration issues.

I'm mentally tracing the call paths, and they *should* be called from the `fs/crypto/policy.c` and `fs/crypto/keysetup.c` files. This is where the core policy management and key setup logic reside, so it makes sense that these functions would be invoked from those code paths. I need to make sure the build and runtime configs are set up to actually allow them to be called.

{
  "Expression": "fscrypt_select_encryption_impl",
  "PathPrefix": "fs/crypto/"
}

{
  "Output": "fs/crypto/fscrypt_private.h=410=void fscrypt_hkdf_expand(const struct hmac_sha512_key *hkdf, u8 context,\n--\nfs/crypto/fscrypt_private.h-415-#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT\nfs/crypto/fscrypt_private.h:416:int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci,\nfs/crypto/fscrypt_private.h-417-\t\t\t\t   bool is_hw_wrapped_key);\n--\nfs/crypto/fscrypt_private.h=442=fscrypt_is_key_prepared(const struct fscrypt_prepared_key *prep_key,\n--\nfs/crypto/fscrypt_private.h-451-\nfs/crypto/fscrypt_private.h:452:static inline int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci,\nfs/crypto/fscrypt_private.h-453-\t\t\t\t\t\t bool is_hw_wrapped_key)\n--\nfs/crypto/inline_crypt.c=64=static void fscrypt_log_blk_crypto_impl(struct fscrypt_mode *mode,\n--\nfs/crypto/inline_crypt.c-84-/* Enable inline encryption for this file if supported. */\nfs/crypto/inline_crypt.c:85:int fscrypt_select_encryption_impl(struct fscrypt_inode_info *ci,\nfs/crypto/inline_crypt.c-86-\t\t\t\t   bool is_hw_wrapped_key)\n--\nfs/crypto/keysetup.c=482=static int setup_file_encryption_key(struct fscrypt_inode_info *ci,\n--\nfs/crypto/keysetup.c-517-\nfs/crypto/keysetup.c:518:\t\terr = fscrypt_select_encryption_impl(ci, false);\nfs/crypto/keysetup.c-519-\t\tif (err)\n--\nfs/crypto/keysetup.c-542-\nfs/crypto/keysetup.c:543:\terr = fscrypt_select_encryption_impl(ci, mk-\u003emk_secret.is_hw_wrapped);\nfs/crypto/keysetup.c-544-\tif (err)\n"
}

gemini-3.1-pro-preview

							input: 9326
							output: 183
							thoughts: 442

**Analyzing the Inline Encryption Patch**

Okay, so I've got a patch here that's changing the allocation strategy for block device arrays, specifically within the context of inline encryption, and how it's handled in `fscrypt_get_devices` and `f2fs_get_devices`. Instead of dynamic heap allocation (`kmalloc_obj`), it looks like they're moving to a fixed-size, stack-allocated array. This clearly impacts the setup and teardown paths for inline encryption.

My immediate concern? This screams fuzzing opportunity. We need to zero in on these inline encryption paths to ensure there's no stack corruption or out-of-bounds access happening, especially considering F2FS and the potential for multiple devices.

Let me make sure I have the function names right. *Checks...* Yep, `f2fs_get_devices` is indeed the correct name. Now, about `fscrypt_get_devices`... *Double checks...* Ah, it's static! That means it might be inlined, which makes it less useful as a direct fuzzing target. We're better off focusing on the callers: `fscrypt_select_encryption_impl`, `fscrypt_prepare_inline_crypt_key`, and `fscrypt_destroy_inline_crypt_key`. Those are definitely the places to start.

Now, `f2fs_get_devices` is also static within the F2FS code, but it's assigned to a function pointer, `f2fs_cryptops.get_devices`. That means it's not likely to be inlined, and we should definitely keep it on the radar as a focus symbol.

Okay, I think I have a solid understanding of the implications and a clear fuzzing strategy. Time to call `set-results`.

{
  "EnableConfigs": [
    "FS_ENCRYPTION_INLINE_CRYPT",
    "BLK_INLINE_ENCRYPTION",
    "F2FS_FS"
  ],
  "FocusSymbols": [
    "fscrypt_select_encryption_impl",
    "fscrypt_prepare_inline_crypt_key",
    "fscrypt_destroy_inline_crypt_key",
    "f2fs_get_devices"
  ],
  "Reasoning": "The patch changes how block device arrays are allocated in fscrypt and f2fs, moving from dynamic heap allocation to a fixed-size stack array. This affects inline encryption setup and teardown paths. Fuzzing should focus on these paths to ensure no stack corruption or out-of-bounds access occurs, especially with multiple devices in f2fs.",
  "WorthFuzzing": true
}

{
  "EnableConfigs": [
    "FS_ENCRYPTION_INLINE_CRYPT",
    "BLK_INLINE_ENCRYPTION",
    "F2FS_FS"
  ],
  "FocusSymbols": [
    "fscrypt_select_encryption_impl",
    "fscrypt_prepare_inline_crypt_key",
    "fscrypt_destroy_inline_crypt_key",
    "f2fs_get_devices"
  ],
  "Reasoning": "The patch changes how block device arrays are allocated in fscrypt and f2fs, moving from dynamic heap allocation to a fixed-size stack array. This affects inline encryption setup and teardown paths. Fuzzing should focus on these paths to ensure no stack corruption or out-of-bounds access occurs, especially with multiple devices in f2fs.",
  "WorthFuzzing": true
}

LLM Calls Summary:
Total Calls	Total Tokens	Avg Tokens	Total Duration (Seconds)	Avg Duration (Seconds)

Tool Calls Summary:
Total Calls	Total Duration (Seconds)	Avg Duration (Seconds)