[moderation] [fs?] KCSAN: data-race in do_fcntl / selinux_file_fcntl

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7006fe2f7f78 Merge tag 'x86-urgent-2024-08-11' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=171e72f3980000
kernel config: https://syzkaller.appspot.com/x/.config?x=cb57e6ebf675f9d2
dashboard link: https://syzkaller.appspot.com/bug?extid=b5e0dfc57e7bb9713460
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [alex....@gmail.com bra...@kernel.org chuck...@oracle.com ja...@suse.cz jla...@kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d01fe743c9d4/disk-7006fe2f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d46915b6e0b3/vmlinux-7006fe2f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5265c6a44a02/bzImage-7006fe2f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b5e0df...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in do_fcntl / selinux_file_fcntl

read-write to 0xffff8881043ef848 of 4 bytes by task 11645 on cpu 0:
setfl fs/fcntl.c:82 [inline]
do_fcntl+0xd53/0xe20 fs/fcntl.c:375
__do_sys_fcntl fs/fcntl.c:492 [inline]
__se_sys_fcntl+0xc4/0x190 fs/fcntl.c:477
__x64_sys_fcntl+0x43/0x50 fs/fcntl.c:477
x64_sys_call+0x209e/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:73
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881043ef848 of 4 bytes by task 11644 on cpu 1:
selinux_file_fcntl+0x138/0x1e0 security/selinux/hooks.c:3894
security_file_fcntl+0x4b/0x80 security/security.c:2924
__do_sys_fcntl fs/fcntl.c:490 [inline]
__se_sys_fcntl+0x88/0x190 fs/fcntl.c:477
__x64_sys_fcntl+0x43/0x50 fs/fcntl.c:477
x64_sys_call+0x209e/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:73
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00002001 -> 0x00006c01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 11644 Comm: syz.3.1794 Not tainted 6.11.0-rc2-syzkaller-00315-g7006fe2f7f78 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.