AI Trajectory

null

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "KMSANReasoning": "",
  "NeedsKMSAN": false,
  "Reasoning": "The patch only modifies user-space selftests in tools/testing/selftests/drivers/net/hw/tso.py, which does not affect the compiled kernel image (vmlinux) or kernel modules.",
  "WorthFuzzing": false
}

null

{
  "PatchDiff": "commit b65442931a50cf1ec809b8454df88f0284065cdb\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Wed Sep 23 20:51:34 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/tools/testing/selftests/drivers/net/hw/tso.py b/tools/testing/selftests/drivers/net/hw/tso.py\nindex 67f6c9ca9a647..176ddf97fabb9 100755\n--- a/tools/testing/selftests/drivers/net/hw/tso.py\n+++ b/tools/testing/selftests/drivers/net/hw/tso.py\n@@ -4,6 +4,7 @@\n \"\"\"A simple test for TSO.\"\"\"\n \n import fcntl\n+import mmap\n import socket\n import struct\n import termios\n@@ -15,6 +16,87 @@ from lib.py import EthtoolFamily, NetdevFamily, NetDrvEpEnv\n from lib.py import bkg, cmd, defer, ethtool, ip, rand_port, wait_port_listen\n \n \n+MAP_HUGETLB = getattr(mmap, \"MAP_HUGETLB\", 0x40000)\n+MSG_ZEROCOPY = getattr(socket, \"MSG_ZEROCOPY\", 0x4000000)\n+SO_ZEROCOPY = getattr(socket, \"SO_ZEROCOPY\", 60)\n+\n+GSO_LEGACY_MAX_SIZE = 65536\n+\n+# Pool of the default hugepage size, the one /proc/meminfo reports on.\n+NR_HUGEPAGES = \"/proc/sys/vm/nr_hugepages\"\n+\n+\n+def default_huge_page_size():\n+    \"\"\"Return the hugepage size in bytes\"\"\"\n+    try:\n+        with open(\"/proc/meminfo\", encoding=\"utf-8\") as meminfo:\n+            for line in meminfo:\n+                if line.startswith(\"Hugepagesize:\"):\n+                    return int(line.split()[1]) * 1024\n+    except OSError:\n+        pass\n+\n+    return 2 * 1024 * 1024\n+\n+\n+def hugepages_free():\n+    \"\"\"Return the number of unused hugepages of the default size.\"\"\"\n+    try:\n+        with open(\"/proc/meminfo\", encoding=\"utf-8\") as meminfo:\n+            for line in meminfo:\n+                if line.startswith(\"HugePages_Free:\"):\n+                    return int(line.split()[1])\n+    except OSError:\n+        pass\n+    return 0\n+\n+\n+def set_nr_hugepages(count):\n+    with open(NR_HUGEPAGES, \"w\", encoding=\"utf-8\") as sysctl:\n+        sysctl.write(f\"{count}\\n\")\n+\n+\n+def tx_dropped(ifname):\n+    with open(f\"/sys/class/net/{ifname}/statistics/tx_dropped\",\n+              encoding=\"utf-8\") as counter:\n+        return int(counter.read())\n+\n+\n+def setup_hugepage():\n+    \"\"\"Reserve one hugepage, and put the pool back afterwards.\"\"\"\n+    if hugepages_free() \u003e= 1:\n+        return\n+\n+    try:\n+        with open(NR_HUGEPAGES, encoding=\"utf-8\") as sysctl:\n+            old_count = int(sysctl.read())\n+        set_nr_hugepages(old_count + 1)\n+    except OSError as error:\n+        raise KsftSkipEx(f\"Unable to reserve a hugepage: {error}\") from error\n+\n+    defer(set_nr_hugepages, old_count)\n+\n+    if hugepages_free() \u003c 1:\n+        raise KsftSkipEx(\"Unable to reserve a hugepage\")\n+\n+\n+def mmap_large_buffer():\n+    \"\"\"Allocate a buffer backed by one huge page.\"\"\"\n+    size = default_huge_page_size()\n+\n+    setup_hugepage()\n+\n+    try:\n+        return mmap.mmap(-1, size,\n+                         flags=mmap.MAP_PRIVATE |\n+                               mmap.MAP_ANONYMOUS |\n+                               MAP_HUGETLB,\n+                         prot=mmap.PROT_READ)\n+    except OSError as e:\n+        raise KsftSkipEx(f\"Unable to allocate a {size \u003e\u003e 20}MB hugepage \"\n+                         f\"buffer: {e}\") from e\n+\n+\n def sock_wait_drain(sock, max_wait=1000):\n     \"\"\"Wait for all pending write data on the socket to get ACKed.\"\"\"\n     for _ in range(max_wait):\n@@ -33,6 +115,32 @@ def tcp_sock_get_retrans(sock):\n     return struct.unpack(\"I\", info[100:104])[0]\n \n \n+def setup_big_tcp(cfg):\n+    \"\"\"Lift the GSO ceiling to what the device advertises for TSO.\"\"\"\n+    if cfg.dev[\"tso_max_size\"] \u003c= GSO_LEGACY_MAX_SIZE:\n+        raise KsftSkipEx(\"Device does not support BIG TCP\")\n+\n+    ip(f\"link set dev {cfg.ifname} \"\n+       f\"gso_max_size {cfg.dev['tso_max_size']} \"\n+       f\"gso_ipv4_max_size {cfg.dev['tso_max_size']}\")\n+\n+    defer(ip, f\"link set dev {cfg.ifname} \"\n+              f\"gso_max_size {cfg.dev['gso_max_size']} \"\n+              f\"gso_ipv4_max_size {cfg.dev['gso_ipv4_max_size']}\")\n+\n+\n+def sock_send_zerocopy(sock):\n+    \"\"\"Send with MSG_ZEROCOPY, return the bytes queued.\"\"\"\n+    try:\n+        sock.setsockopt(socket.SOL_SOCKET, SO_ZEROCOPY, 1)\n+    except OSError as e:\n+        raise KsftSkipEx(f\"SO_ZEROCOPY not supported: {e}\") from e\n+\n+    with mmap_large_buffer() as tx_buf:\n+        sock.sendall(tx_buf, MSG_ZEROCOPY)\n+        return len(tx_buf)\n+\n+\n def run_one_stream(cfg, ipver, remote_v4, remote_v6, should_lso):\n     cfg.require_cmd(\"socat\", local=False, remote=True)\n \n@@ -96,6 +204,46 @@ def run_one_stream(cfg, ipver, remote_v4, remote_v6, should_lso):\n                         500, comment=\"Number of LSO wire-packets with LSO disabled\")\n \n \n+def run_big_tcp_stream(cfg, ipver, remote_v4, remote_v6):\n+    \"\"\"Send with MSG_ZEROCOPY out of a huge page, so the frags exceed 64kB.\"\"\"\n+    cfg.require_cmd(\"socat\", local=False, remote=True)\n+\n+    # No clamping, as it would keep the frags under 64kB\n+    port = rand_port()\n+    listen_opts = f\"{port},reuseport\"\n+    listen_cmd = f\"socat -{ipver} -t 2 -u TCP-LISTEN:{listen_opts} /dev/null,ignoreeof\"\n+\n+    with bkg(listen_cmd, host=cfg.remote, exit_wait=True):\n+        wait_port_listen(port, host=cfg.remote)\n+\n+        if ipver == \"4\":\n+            sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)\n+            sock.connect((remote_v4, port))\n+        else:\n+            sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)\n+            sock.connect((remote_v6, port))\n+\n+        # Small send to make sure the connection is working.\n+        sock.send(\"ping\".encode())\n+        sock_wait_drain(sock)\n+\n+        retrans_old = tcp_sock_get_retrans(sock)\n+        drops_old = tx_dropped(cfg.ifname)\n+\n+        sent = sock_send_zerocopy(sock)\n+        sock_wait_drain(sock)\n+\n+        drops = tx_dropped(cfg.ifname) - drops_old\n+        retrans = tcp_sock_get_retrans(sock) - retrans_old\n+        sock.close()\n+\n+        ksft_eq(drops, 0, comment=\"Driver TX drops during BIG TCP send\")\n+\n+        # Same best effort bound as the plain stream.\n+        total_lso_wire = sent * 0.90 // cfg.dev[\"mtu\"]\n+        ksft_lt(retrans, total_lso_wire / 16)\n+\n+\n def build_tunnel(cfg, outer_ipver, tun_info):\n     local_v4  = NetDrvEpEnv.nsim_v4_pfx + \"1\"\n     local_v6  = NetDrvEpEnv.nsim_v6_pfx + \"1\"\n@@ -147,6 +295,11 @@ def test_builder(name, cfg, outer_ipver, feature, tun=None, inner_ipver=None):\n         if feature not in cfg.hw_features:\n             raise KsftSkipEx(f\"Device does not support {feature}\")\n \n+        # Run non-tunnel test cases under the BIG TCP limits too.\n+        big_tcp = \"big_tcp\" in name\n+        if big_tcp:\n+            setup_big_tcp(cfg)\n+\n         ipver = outer_ipver\n         if tun:\n             remote_v4, remote_v6 = build_tunnel(cfg, ipver, tun)\n@@ -159,6 +312,9 @@ def test_builder(name, cfg, outer_ipver, feature, tun=None, inner_ipver=None):\n         ethtool(f\"-K {cfg.ifname} {feature} off\")\n         run_one_stream(cfg, ipver, remote_v4, remote_v6, should_lso=False)\n \n+        if big_tcp:\n+            run_big_tcp_stream(cfg, ipver, remote_v4, remote_v6)\n+\n         ethtool(f\"-K {cfg.ifname} tx-gso-partial off\")\n         ethtool(f\"-K {cfg.ifname} tx-tcp-mangleid-segmentation off\")\n         if feature in cfg.partial_features:\n@@ -171,6 +327,9 @@ def test_builder(name, cfg, outer_ipver, feature, tun=None, inner_ipver=None):\n         ethtool(f\"-K {cfg.ifname} {feature} on\")\n         run_one_stream(cfg, ipver, remote_v4, remote_v6, should_lso=True)\n \n+        if big_tcp:\n+            run_big_tcp_stream(cfg, ipver, remote_v4, remote_v6)\n+\n     f.__name__ = name + ((outer_ipver + \"_\") if tun else \"\") + \"ipv\" + inner_ipver\n     return f\n \n@@ -230,6 +389,8 @@ def main() -\u003e None:\n             # name,       v4/v6  ethtool_feature               tun:(type, args, inner ip versions)\n             (\"\",           \"4\", \"tx-tcp-segmentation\",         None),\n             (\"\",           \"6\", \"tx-tcp6-segmentation\",        None),\n+            (\"big_tcp_\",   \"4\", \"tx-tcp-segmentation\",         None),\n+            (\"big_tcp_\",   \"6\", \"tx-tcp6-segmentation\",        None),\n             (\"vxlan\",      \"4\", \"tx-udp_tnl-segmentation\",     (\"vxlan\", \"id 100 dstport 4789 noudpcsum\", (\"4\", \"6\"))),\n             (\"vxlan\",      \"6\", \"tx-udp_tnl-segmentation\",     (\"vxlan\", \"id 100 dstport 4789 udp6zerocsumtx udp6zerocsumrx\", (\"4\", \"6\"))),\n             (\"vxlan_csum\", \"\", \"tx-udp_tnl-csum-segmentation\", (\"vxlan\", \"id 100 dstport 4789 udpcsum\", (\"4\", \"6\"))),\n"
}

core

null

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only modifies user-space selftests in tools/testing/selftests/drivers/net/hw/tso.py, which does not affect the compiled kernel image (vmlinux) or kernel modules.",
  "WorthFuzzing": false
}

You are an expert Linux kernel maintainer and security engineer.
Your job is to review a provided patch series and evaluate whether it warrants fuzzing with syzkaller.

IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in
your workspace. Do NOT rely on internal assumptions. You must actively use your code access
tools to inspect the actual source code, callers, and surrounding context.

================================================================================
1. CORE TRIAGE PHILOSOPHY
================================================================================
The goal of patch fuzzing is to discover crashes, regressions, exposed latent bugs,
and newly triggered assertions introduced by the patch series.

- REACHABILITY IS THE PRIMARY GATE:
  Fuzzing can only discover bugs in code that can actually execute in standard virtualized
  environments (GCE or QEMU, utilizing software-emulated devices like USB gadgets, netdev, tun/tap).
  If the modified code is structurally unreachable (see Section 2), it MUST NOT be fuzzed,
  regardless of whether it adds assertions or complex logic.

- DO NOT BLINDLY TRUST "NO FUNCTIONAL CHANGE" (NFCI) OR "REFACTORING" CLAIMS:
  Patch authors routinely label changes as "cleanups", "refactorings", or state
  "No functional change intended". Do NOT take these claims at face value.
  Code refactorings that rearrange logic, introduce helper functions, or alter state management
  in core subsystems frequently introduce subtle semantic shifts or uncover latent kernel bugs.
  If reachable executable code is modified or refactored, it MUST be fuzzed.

- NEW OR MODIFIED ASSERTIONS IN REACHABLE CODE MUST BE FUZZED:
  When a patch introduces or modifies runtime checks or assertions (e.g., WARN_ON*, VM_WARN_ON*,
  BUG_ON*, lockdep_assert*) in reachable code paths, it enforces new or stricter invariants.
  Even if the author believes the invariant always holds, fuzzing is essential to verify whether
  an unusual sequence of operations can violate it.

================================================================================
2. WHEN TO RETURN WorthFuzzing=false (NEGATIVE CRITERIA)
================================================================================
Return WorthFuzzing=false ONLY IF all modified code falls strictly into one or more of these categories:

- Non-kernel and non-executable changes:
  * Modifications to Documentation/, comments, or spelling fixes.
  * User-space directories, self-tests, samples, or scripts (e.g., tools/, samples/, scripts/, usr/)
    that do not affect the compiled kernel image (vmlinux) or kernel modules.
  * Purely decorative logging (e.g., message strings in pr_err, printk, dev_info) or tracepoints
    that do not alter control flow or data structures.
  * Build system or Kconfig changes that do not alter compiled C logic.
- Structurally unreachable hardware:
  * Vendor-specific PCIe switches, SmartNICs, or GPU drivers (e.g., mlxsw, pds_core, qed,
    ionic, amdgpu) requiring physical ASIC/PCIe cards not emulated in standard QEMU.
- Unreachable execution paths:
  * Driver teardown callbacks (.remove, .shutdown, pci_unregister_driver) executed only during
    physical PCI hot-unplug or manual sysfs driver unbinding.
  * Code paths exclusive to architectures other than the target architecture.

================================================================================
3. WHEN TO RETURN WorthFuzzing=true (POSITIVE CRITERIA)
================================================================================
Return WorthFuzzing=true whenever the patch touches reachable executable code, including:
- Core Subsystems:
  * Any logic modifications in memory management (mm/), synchronization/locking (kernel/locking/),
    BPF, scheduler, core networking, VFS, or syscall handling.
- Refactorings and Code Cleanups:
  * Any restructuring of reachable data structures, helper abstractions, or algorithm flows.
- Runtime Assertions and Defensive Checks:
  * Any introduction or alteration of assertions (WARN_ON*, VM_WARN_ON*, BUG_ON*, etc.) in reachable paths.
- Reachable Drivers and Protocols:
  * Drivers accessible via virtual buses (virtio, USB gadget, loopback, netlink, binder, sockets, etc.).

================================================================================
4. EXTRACTING FocusSymbols (PREVENTING DILUTION)
================================================================================
When WorthFuzzing=true, you must extract specific kernel functions into FocusSymbols to guide the fuzzer:

- AVOID UBIQUITOUS LIFECYCLE HOT-PATHS:
  Do NOT list generic, ubiquitous functions called by almost every program in the corpus
  (including, but not limited to: general memory allocators and deallocators, page fault
  and trap handlers, or core synchronization primitives; this is not an exhaustive list).
  Listing ubiquitous functions causes the fuzzer to classify thousands of unrelated tests as "focused",
  which severely dilutes fuzzing effort away from the actual changes.

- TARGET SPECIFIC FEATURE LOGIC AND ENTRYPOINTS:
  List functions that specifically implement the logic being added or altered, or direct API entrypoints
  for the subsystem feature under review.

- HANDLING STATIC INLINE FUNCTIONS IN HEADERS (.h):
  Compiler-inlined static functions (such as static inlines in mm/*.h or include/linux/*.h) lack
  distinct symbol addresses in vmlinux and cannot be targeted directly by symbol coverage filters.
  If the changes are primarily in static inline helpers, identify non-static, feature-specific caller
  functions in .c files that exercise them (avoiding ubiquitous lifecycle wrappers).

================================================================================
5. IDENTIFYING EnableConfigs
================================================================================
Identify any specific CONFIG_ options required to properly compile and reach the modified code:
- Inspect Kconfig files and #ifdef guards; do not make assumptions.
- Check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed.
- Strip any '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.

Target architecture: amd64

For your convenience, here is the diff of the changes:
commit b65442931a50cf1ec809b8454df88f0284065cdb
Author: syz-cluster <triage@syzkaller.com>
Date:   Wed Sep 23 20:51:34 2026 +0000

    syz-cluster: applied patch under review

diff --git a/tools/testing/selftests/drivers/net/hw/tso.py b/tools/testing/selftests/drivers/net/hw/tso.py
index 67f6c9ca9a647..176ddf97fabb9 100755
--- a/tools/testing/selftests/drivers/net/hw/tso.py
+++ b/tools/testing/selftests/drivers/net/hw/tso.py
@@ -4,6 +4,7 @@
 """A simple test for TSO."""
 
 import fcntl
+import mmap
 import socket
 import struct
 import termios
@@ -15,6 +16,87 @@ from lib.py import EthtoolFamily, NetdevFamily, NetDrvEpEnv
 from lib.py import bkg, cmd, defer, ethtool, ip, rand_port, wait_port_listen
 
 
+MAP_HUGETLB = getattr(mmap, "MAP_HUGETLB", 0x40000)
+MSG_ZEROCOPY = getattr(socket, "MSG_ZEROCOPY", 0x4000000)
+SO_ZEROCOPY = getattr(socket, "SO_ZEROCOPY", 60)
+
+GSO_LEGACY_MAX_SIZE = 65536
+
+# Pool of the default hugepage size, the one /proc/meminfo reports on.
+NR_HUGEPAGES = "/proc/sys/vm/nr_hugepages"
+
+
+def default_huge_page_size():
+    """Return the hugepage size in bytes"""
+    try:
+        with open("/proc/meminfo", encoding="utf-8") as meminfo:
+            for line in meminfo:
+                if line.startswith("Hugepagesize:"):
+                    return int(line.split()[1]) * 1024
+    except OSError:
+        pass
+
+    return 2 * 1024 * 1024
+
+
+def hugepages_free():
+    """Return the number of unused hugepages of the default size."""
+    try:
+        with open("/proc/meminfo", encoding="utf-8") as meminfo:
+            for line in meminfo:
+                if line.startswith("HugePages_Free:"):
+                    return int(line.split()[1])
+    except OSError:
+        pass
+    return 0
+
+
+def set_nr_hugepages(count):
+    with open(NR_HUGEPAGES, "w", encoding="utf-8") as sysctl:
+        sysctl.write(f"{count}\n")
+
+
+def tx_dropped(ifname):
+    with open(f"/sys/class/net/{ifname}/statistics/tx_dropped",
+              encoding="utf-8") as counter:
+        return int(counter.read())
+
+
+def setup_hugepage():
+    """Reserve one hugepage, and put the pool back afterwards."""
+    if hugepages_free() >= 1:
+        return
+
+    try:
+        with open(NR_HUGEPAGES, encoding="utf-8") as sysctl:
+            old_count = int(sysctl.read())
+        set_nr_hugepages(old_count + 1)
+    except OSError as error:
+        raise KsftSkipEx(f"Unable to reserve a hugepage: {error}") from error
+
+    defer(set_nr_hugepages, old_count)
+
+    if hugepages_free() < 1:
+        raise KsftSkipEx("Unable to reserve a hugepage")
+
+
+def mmap_large_buffer():
+    """Allocate a buffer backed by one huge page."""
+    size = default_huge_page_size()
+
+    setup_hugepage()
+
+    try:
+        return mmap.mmap(-1, size,
+                         flags=mmap.MAP_PRIVATE |
+                               mmap.MAP_ANONYMOUS |
+                               MAP_HUGETLB,
+                         prot=mmap.PROT_READ)
+    except OSError as e:
+        raise KsftSkipEx(f"Unable to allocate a {size >> 20}MB hugepage "
+                         f"buffer: {e}") from e
+
+
 def sock_wait_drain(sock, max_wait=1000):
     """Wait for all pending write data on the socket to get ACKed."""
     for _ in range(max_wait):
@@ -33,6 +115,32 @@ def tcp_sock_get_retrans(sock):
     return struct.unpack("I", info[100:104])[0]
 
 
+def setup_big_tcp(cfg):
+    """Lift the GSO ceiling to what the device advertises for TSO."""
+    if cfg.dev["tso_max_size"] <= GSO_LEGACY_MAX_SIZE:
+        raise KsftSkipEx("Device does not support BIG TCP")
+
+    ip(f"link set dev {cfg.ifname} "
+       f"gso_max_size {cfg.dev['tso_max_size']} "
+       f"gso_ipv4_max_size {cfg.dev['tso_max_size']}")
+
+    defer(ip, f"link set dev {cfg.ifname} "
+              f"gso_max_size {cfg.dev['gso_max_size']} "
+              f"gso_ipv4_max_size {cfg.dev['gso_ipv4_max_size']}")
+
+
+def sock_send_zerocopy(sock):
+    """Send with MSG_ZEROCOPY, return the bytes queued."""
+    try:
+        sock.setsockopt(socket.SOL_SOCKET, SO_ZEROCOPY, 1)
+    except OSError as e:
+        raise KsftSkipEx(f"SO_ZEROCOPY not supported: {e}") from e
+
+    with mmap_large_buffer() as tx_buf:
+        sock.sendall(tx_buf, MSG_ZEROCOPY)
+        return len(tx_buf)
+
+
 def run_one_stream(cfg, ipver, remote_v4, remote_v6, should_lso):
     cfg.require_cmd("socat", local=False, remote=True)
 
@@ -96,6 +204,46 @@ def run_one_stream(cfg, ipver, remote_v4, remote_v6, should_lso):
                         500, comment="Number of LSO wire-packets with LSO disabled")
 
 
+def run_big_tcp_stream(cfg, ipver, remote_v4, remote_v6):
+    """Send with MSG_ZEROCOPY out of a huge page, so the frags exceed 64kB."""
+    cfg.require_cmd("socat", local=False, remote=True)
+
+    # No clamping, as it would keep the frags under 64kB
+    port = rand_port()
+    listen_opts = f"{port},reuseport"
+    listen_cmd = f"socat -{ipver} -t 2 -u TCP-LISTEN:{listen_opts} /dev/null,ignoreeof"
+
+    with bkg(listen_cmd, host=cfg.remote, exit_wait=True):
+        wait_port_listen(port, host=cfg.remote)
+
+        if ipver == "4":
+            sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+            sock.connect((remote_v4, port))
+        else:
+            sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
+            sock.connect((remote_v6, port))
+
+        # Small send to make sure the connection is working.
+        sock.send("ping".encode())
+        sock_wait_drain(sock)
+
+        retrans_old = tcp_sock_get_retrans(sock)
+        drops_old = tx_dropped(cfg.ifname)
+
+        sent = sock_send_zerocopy(sock)
+        sock_wait_drain(sock)
+
+        drops = tx_dropped(cfg.ifname) - drops_old
+        retrans = tcp_sock_get_retrans(sock) - retrans_old
+        sock.close()
+
+        ksft_eq(drops, 0, comment="Driver TX drops during BIG TCP send")
+
+        # Same best effort bound as the plain stream.
+        total_lso_wire = sent * 0.90 // cfg.dev["mtu"]
+        ksft_lt(retrans, total_lso_wire / 16)
+
+
 def build_tunnel(cfg, outer_ipver, tun_info):
     local_v4  = NetDrvEpEnv.nsim_v4_pfx + "1"
     local_v6  = NetDrvEpEnv.nsim_v6_pfx + "1"
@@ -147,6 +295,11 @@ def test_builder(name, cfg, outer_ipver, feature, tun=None, inner_ipver=None):
         if feature not in cfg.hw_features:
             raise KsftSkipEx(f"Device does not support {feature}")
 
+        # Run non-tunnel test cases under the BIG TCP limits too.
+        big_tcp = "big_tcp" in name
+        if big_tcp:
+            setup_big_tcp(cfg)
+
         ipver = outer_ipver
         if tun:
             remote_v4, remote_v6 = build_tunnel(cfg, ipver, tun)
@@ -159,6 +312,9 @@ def test_builder(name, cfg, outer_ipver, feature, tun=None, inner_ipver=None):
         ethtool(f"-K {cfg.ifname} {feature} off")
         run_one_stream(cfg, ipver, remote_v4, remote_v6, should_lso=False)
 
+        if big_tcp:
+            run_big_tcp_stream(cfg, ipver, remote_v4, remote_v6)
+
         ethtool(f"-K {cfg.ifname} tx-gso-partial off")
         ethtool(f"-K {cfg.ifname} tx-tcp-mangleid-segmentation off")
         if feature in cfg.partial_features:
@@ -171,6 +327,9 @@ def test_builder(name, cfg, outer_ipver, feature, tun=None, inner_ipver=None):
         ethtool(f"-K {cfg.ifname} {feature} on")
         run_one_stream(cfg, ipver, remote_v4, remote_v6, should_lso=True)
 
+        if big_tcp:
+            run_big_tcp_stream(cfg, ipver, remote_v4, remote_v6)
+
     f.__name__ = name + ((outer_ipver + "_") if tun else "") + "ipv" + inner_ipver
     return f
 
@@ -230,6 +389,8 @@ def main() -> None:
             # name,       v4/v6  ethtool_feature               tun:(type, args, inner ip versions)
             ("",           "4", "tx-tcp-segmentation",         None),
             ("",           "6", "tx-tcp6-segmentation",        None),
+            ("big_tcp_",   "4", "tx-tcp-segmentation",         None),
+            ("big_tcp_",   "6", "tx-tcp6-segmentation",        None),
             ("vxlan",      "4", "tx-udp_tnl-segmentation",     ("vxlan", "id 100 dstport 4789 noudpcsum", ("4", "6"))),
             ("vxlan",      "6", "tx-udp_tnl-segmentation",     ("vxlan", "id 100 dstport 4789 udp6zerocsumtx udp6zerocsumrx", ("4", "6"))),
             ("vxlan_csum", "", "tx-udp_tnl-csum-segmentation", ("vxlan", "id 100 dstport 4789 udpcsum", ("4", "6"))),

gemini-3.8-flash

null

null

							input: 5703
							output: 78
							thoughts: 563
						

**Fuzzing Evaluation: Negative Result**

Okay, let's break this down. My initial instinct is to assess whether this patch series, or more precisely this single patch, warrants syzkaller fuzzing. The key file modified is `tools/testing/selftests/drivers/net/hw/tso.py`. I immediately recall the guidelines, specifically the "NEGATIVE CRITERIA" – the conditions where we explicitly *don't* fuzz. Let me quickly run through them...

Right. The modification is *solely* within `tools/testing/selftests/...`. That’s squarely in user-space, a self-test script in the `tools` directory. And that script *definitely* doesn't touch the kernel image or any modules. Therefore, according to the second rule listed, this is a clear-cut case for `WorthFuzzing=false`. The change is non-kernel, non-executable, falling precisely into the category of "User-space directories, self-tests... that do not affect the compiled kernel image..."

I'll quickly double-check the commit `b65442931a50cf1ec809b8454df88f0284065cdb` to be certain there are no other hidden changes in a different file or commit, but it confirms only the same file: `tools/testing/selftests/drivers/net/hw/tso.py` is changed.

Therefore, the assessment is straightforward. I'll set:

*   `WorthFuzzing: false`
*   `FocusSymbols: []`
*   `EnableConfigs: []`
*   `Reasoning: "The patch only modifies user-space selftests in tools/testing/selftests/drivers/net/hw/tso.py, which does not affect the compiled kernel image (vmlinux) or kernel modules."`

This is a pretty simple call, given the rules.

{
  "EnableConfigs": [],
  "FocusSymbols": [],
  "Reasoning": "The patch only modifies user-space selftests in tools/testing/selftests/drivers/net/hw/tso.py, which does not affect the compiled kernel image (vmlinux) or kernel modules.",
  "WorthFuzzing": false
}

{
  "EnableConfigs": null,
  "FocusSymbols": [],
  "Reasoning": "The patch only modifies user-space selftests in tools/testing/selftests/drivers/net/hw/tso.py, which does not affect the compiled kernel image (vmlinux) or kernel modules.",
  "WorthFuzzing": false
}

{
  "WorthFuzzing": false
}

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