[moderation] [fs?] KCSAN: data-race in fsnotify / fsnotify_detach_connector_from_object (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: dccb07f2914c Merge tag 'for-6.9-rc7-tag' of git://git.kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=156d1ea8980000
kernel config: https://syzkaller.appspot.com/x/.config?x=168fab99759dff68
dashboard link: https://syzkaller.appspot.com/bug?extid=8049759a3f6c9b61f219
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [amir...@gmail.com ja...@suse.cz linux-...@vger.kernel.org linux-...@vger.kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3c2d87fc08e4/disk-dccb07f2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2722c4f79b5b/vmlinux-dccb07f2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b652f5cb7bf8/bzImage-dccb07f2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+804975...@syzkaller.appspotmail.com

EXT4-fs (loop4): unmounting filesystem 00000005-0000-0000-0000-000000000000.
==================================================================
BUG: KCSAN: data-race in fsnotify / fsnotify_detach_connector_from_object

write to 0xffff8881001ce904 of 4 bytes by task 4005 on cpu 0:
fsnotify_detach_connector_from_object+0xcc/0x280 fs/notify/mark.c:253
fsnotify_put_mark+0x198/0x3c0 fs/notify/mark.c:316
__do_sys_inotify_rm_watch fs/notify/inotify/inotify_user.c:819 [inline]
__se_sys_inotify_rm_watch+0x105/0x180 fs/notify/inotify/inotify_user.c:793
__x64_sys_inotify_rm_watch+0x31/0x40 fs/notify/inotify/inotify_user.c:793
x64_sys_call+0x2735/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:256
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881001ce904 of 4 bytes by task 3099 on cpu 1:
fsnotify+0x2b9/0x1160 fs/notify/fsnotify.c:538
__fsnotify_parent+0x285/0x370 fs/notify/fsnotify.c:236
fsnotify_parent include/linux/fsnotify.h:83 [inline]
fsnotify_file include/linux/fsnotify.h:106 [inline]
fsnotify_close include/linux/fsnotify.h:387 [inline]
__fput+0x1ff/0x660 fs/file_table.c:408
__fput_sync+0x44/0x60 fs/file_table.c:507
__do_sys_close fs/open.c:1556 [inline]
__se_sys_close+0x101/0x1b0 fs/open.c:1541
__x64_sys_close+0x1f/0x30 fs/open.c:1541
x64_sys_call+0x25b9/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:4
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00002008 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3099 Comm: syz-executor.4 Not tainted 6.9.0-rc7-syzkaller-00012-gdccb07f2914c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================


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[syzbot]

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