[moderation] [trace?] KCSAN: data-race in do_readlinkat / ring_buffer_unlock_commit

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8ba098e6b6ff Merge tag 'v7.2-rc5-smb3-client-fixes' of git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16cf7a49580000
kernel config: https://syzkaller.appspot.com/x/.config?x=84b3039e8461eef5
dashboard link: https://syzkaller.appspot.com/bug?extid=b8ae432e1ee56705cb71
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
CC: [linux-...@vger.kernel.org linux-tra...@vger.kernel.org mathieu....@efficios.com mhir...@kernel.org ros...@goodmis.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9b4a066485c3/disk-8ba098e6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fcd2fa969b75/vmlinux-8ba098e6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/47617c2a5b49/bzImage-8ba098e6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b8ae43...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in do_readlinkat / ring_buffer_unlock_commit

read to 0xffff888100074cb4 of 1 bytes by task 14450 on cpu 1:

write to 0xffff888100074cb4 of 1 bytes by task 14466 on cpu 0:
rb_wakeups kernel/trace/ring_buffer.c:4294 [inline]
ring_buffer_unlock_commit+0x6a/0x440 kernel/trace/ring_buffer.c:4494
__buffer_unlock_commit kernel/trace/trace.h:1697 [inline]
trace_buffer_unlock_commit_regs+0x43/0x310 kernel/trace/trace.c:2049
trace_event_buffer_commit+0x149/0x590 kernel/trace/trace.c:2024
do_trace_event_raw_event_x86_fpu arch/x86/include/asm/trace/fpu.h:10 [inline]
trace_event_raw_event_x86_fpu+0x165/0x200 arch/x86/include/asm/trace/fpu.h:10
__do_trace_x86_fpu_regs_activated arch/x86/include/asm/trace/fpu.h:47 [inline]
trace_x86_fpu_regs_activated arch/x86/include/asm/trace/fpu.h:47 [inline]
fpregs_activate arch/x86/kernel/fpu/context.h:50 [inline]
fpregs_mark_activate+0xff/0x120 arch/x86/kernel/fpu/core.c:924
restore_fpregs_from_user arch/x86/kernel/fpu/signal.c:322 [inline]
__fpu_restore_sig arch/x86/kernel/fpu/signal.c:351 [inline]
fpu__restore_sig+0x5a0/0xad0 arch/x86/kernel/fpu/signal.c:485
restore_sigcontext arch/x86/kernel/signal_64.c:95 [inline]
__ia32_sys_rt_sigreturn+0x29b/0x350 arch/x86/kernel/signal_64.c:268
x64_sys_call+0x2823/0x3020 arch/x86/include/generated/asm/syscalls_64.h:16
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x01 -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 14466 Comm: syz.5.4072 Tainted: G W syzkaller #0 PREEMPT(lazy)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
==================================================================


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