[moderation] [fs?] KCSAN: data-race in fasync_remove_entry / kill_fasync (12)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: da4373fbcf00 Merge tag 'thermal-6.12-rc7' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=174dc35f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=e351f666e62e0b06
dashboard link: https://syzkaller.appspot.com/bug?extid=7d99a59af4579ca231ab
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/369ccd80b5e5/disk-da4373fb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/145cd34bb2e3/vmlinux-da4373fb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f3cc42e7e190/bzImage-da4373fb.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7d99a5...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in fasync_remove_entry / kill_fasync

write to 0xffff88811290e748 of 8 bytes by task 4251 on cpu 1:
fasync_remove_entry+0xd2/0x130 fs/fcntl.c:1008
fasync_helper+0x96/0xc0 fs/fcntl.c:1107
pipe_fasync+0x85/0x160 fs/pipe.c:754
__fput+0x664/0x6d0 fs/file_table.c:428
__fput_sync+0x43/0x60 fs/file_table.c:516
__do_sys_close fs/open.c:1567 [inline]
__se_sys_close+0xf9/0x1a0 fs/open.c:1552
__x64_sys_close+0x1f/0x30 fs/open.c:1552
x64_sys_call+0x25cb/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:4
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 0xffff88811290e748 of 8 bytes by task 4246 on cpu 0:
kill_fasync+0x24/0x170 fs/fcntl.c:1149
wakeup_pipe_readers fs/splice.c:183 [inline]
splice_file_to_pipe+0x311/0x390 fs/splice.c:1298
do_splice+0xc8b/0x1120 fs/splice.c:1379
__do_splice fs/splice.c:1436 [inline]
__do_sys_splice fs/splice.c:1652 [inline]
__se_sys_splice+0x24c/0x390 fs/splice.c:1634
__x64_sys_splice+0x78/0x90 fs/splice.c:1634
x64_sys_call+0x2945/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:276
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: 0xffff888104bc0630 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 4246 Comm: syz.1.273 Not tainted 6.12.0-rc6-syzkaller-00272-gda4373fbcf00 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================


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[syzbot]

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