[moderation] [autofs?] KCSAN: data-race in autofs_wait / autofs_wait

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 20b64cf8705a Merge tag 'tsm-for-7.1' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1172916a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2e40c0f41e01837e
dashboard link: https://syzkaller.appspot.com/bug?extid=c6d286fd51860df64d9a
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
CC: [aut...@vger.kernel.org linux-...@vger.kernel.org ra...@themaw.net]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/845d599cfcfd/disk-20b64cf8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/df7c4432478c/vmlinux-20b64cf8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7f57e3d8b373/bzImage-20b64cf8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c6d286...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in autofs_wait / autofs_wait

write to 0xffffffff86dffac0 of 4 bytes by task 6635 on cpu 0:
autofs_wait+0x8d5/0xbe0 fs/autofs/waitq.c:-1
autofs_mount_wait+0xc2/0x100 fs/autofs/root.c:256
autofs_d_automount+0x3f6/0x560 fs/autofs/root.c:410
follow_automount fs/namei.c:1560 [inline]
__traverse_mounts+0x256/0x420 fs/namei.c:1613
traverse_mounts fs/namei.c:1642 [inline]
handle_mounts fs/namei.c:1744 [inline]
step_into_slowpath+0x2d5/0x4c0 fs/namei.c:2100
step_into fs/namei.c:2148 [inline]
walk_component fs/namei.c:2284 [inline]
lookup_last fs/namei.c:2785 [inline]
path_lookupat+0x330/0x500 fs/namei.c:2809
filename_lookup+0x190/0x390 fs/namei.c:2838
vfs_statx+0x96/0x170 fs/stat.c:353
vfs_fstatat fs/stat.c:373 [inline]
vfs_lstat include/linux/fs.h:3212 [inline]
__do_sys_newlstat fs/stat.c:524 [inline]
__se_sys_newlstat+0x66/0x3f0 fs/stat.c:518
__x64_sys_newlstat+0x31/0x40 fs/stat.c:518
x64_sys_call+0x1b8c/0x3020 arch/x86/include/generated/asm/syscalls_64.h:7
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffffffff86dffac0 of 4 bytes by task 6611 on cpu 1:
autofs_wait+0x8d5/0xbe0 fs/autofs/waitq.c:-1
autofs_mount_wait+0xc2/0x100 fs/autofs/root.c:256
autofs_d_automount+0x3f6/0x560 fs/autofs/root.c:410
follow_automount fs/namei.c:1560 [inline]
__traverse_mounts+0x256/0x420 fs/namei.c:1613
traverse_mounts fs/namei.c:1642 [inline]
handle_mounts fs/namei.c:1744 [inline]
step_into_slowpath+0x2d5/0x4c0 fs/namei.c:2100
step_into fs/namei.c:2148 [inline]
walk_component fs/namei.c:2284 [inline]
lookup_last fs/namei.c:2785 [inline]
path_lookupat+0x330/0x500 fs/namei.c:2809
filename_lookup+0x190/0x390 fs/namei.c:2838
vfs_statx+0x96/0x170 fs/stat.c:353
vfs_fstatat fs/stat.c:373 [inline]
vfs_lstat include/linux/fs.h:3212 [inline]
__do_sys_newlstat fs/stat.c:524 [inline]
__se_sys_newlstat+0x66/0x3f0 fs/stat.c:518
__x64_sys_newlstat+0x31/0x40 fs/stat.c:518
x64_sys_call+0x1b8c/0x3020 arch/x86/include/generated/asm/syscalls_64.h:7
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000280d -> 0x0000280e

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 6611 Comm: syz.8.698 Tainted: G W syzkaller #0 PREEMPT(full)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================


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