[moderation] [fs?] KMSAN: uninit-value in fsnotify (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a2e94e80790b Merge tag 'block-6.17-20250822' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17418c42580000
kernel config: https://syzkaller.appspot.com/x/.config?x=6ccfdce02093e91f
dashboard link: https://syzkaller.appspot.com/bug?extid=6f986ce970ef077d31dd
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
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/ff05f215d71f/disk-a2e94e80.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f2b79d6d8305/vmlinux-a2e94e80.xz
kernel image: https://storage.googleapis.com/syzbot-assets/13e743bf1472/bzImage-a2e94e80.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6f986c...@syzkaller.appspotmail.com

loop5: detected capacity change from 0 to 40427
=====================================================
BUG: KMSAN: uninit-value in fsnotify_iter_select_report_types fs/notify/fsnotify.c:468 [inline]
BUG: KMSAN: uninit-value in fsnotify+0x1178/0x3f50 fs/notify/fsnotify.c:640
fsnotify_iter_select_report_types fs/notify/fsnotify.c:468 [inline]
fsnotify+0x1178/0x3f50 fs/notify/fsnotify.c:640
__fsnotify_parent+0x8b2/0x9c0 fs/notify/fsnotify.c:287
fsnotify_parent include/linux/fsnotify.h:96 [inline]
fsnotify_path include/linux/fsnotify.h:113 [inline]
fsnotify_file include/linux/fsnotify.h:127 [inline]
fsnotify_close include/linux/fsnotify.h:457 [inline]
__fput+0x490/0x1040 fs/file_table.c:454
fput_close_sync+0xbc/0x210 fs/file_table.c:573
__do_sys_close fs/open.c:1587 [inline]
__se_sys_close fs/open.c:1572 [inline]
__x64_sys_close+0xf0/0x2c0 fs/open.c:1572
x64_sys_call+0x2eb2/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:4
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
fsnotify_iter_select_report_types fs/notify/fsnotify.c:466 [inline]
fsnotify+0x1171/0x3f50 fs/notify/fsnotify.c:640
__fsnotify_parent+0x8b2/0x9c0 fs/notify/fsnotify.c:287
fsnotify_parent include/linux/fsnotify.h:96 [inline]
fsnotify_path include/linux/fsnotify.h:113 [inline]
fsnotify_file include/linux/fsnotify.h:127 [inline]
fsnotify_close include/linux/fsnotify.h:457 [inline]
__fput+0x490/0x1040 fs/file_table.c:454
fput_close_sync+0xbc/0x210 fs/file_table.c:573
__do_sys_close fs/open.c:1587 [inline]
__se_sys_close fs/open.c:1572 [inline]
__x64_sys_close+0xf0/0x2c0 fs/open.c:1572
x64_sys_call+0x2eb2/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:4
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
fsnotify+0x3d14/0x3f50 fs/notify/fsnotify.c:623
__fsnotify_parent+0x8b2/0x9c0 fs/notify/fsnotify.c:287
fsnotify_parent include/linux/fsnotify.h:96 [inline]
fsnotify_path include/linux/fsnotify.h:113 [inline]
fsnotify_file include/linux/fsnotify.h:127 [inline]
fsnotify_close include/linux/fsnotify.h:457 [inline]
__fput+0x490/0x1040 fs/file_table.c:454
fput_close_sync+0xbc/0x210 fs/file_table.c:573
__do_sys_close fs/open.c:1587 [inline]
__se_sys_close fs/open.c:1572 [inline]
__x64_sys_close+0xf0/0x2c0 fs/open.c:1572
x64_sys_call+0x2eb2/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:4
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
slab_post_alloc_hook mm/slub.c:4186 [inline]
slab_alloc_node mm/slub.c:4229 [inline]
kmem_cache_alloc_noprof+0x81b/0xec0 mm/slub.c:4236
fsnotify_attach_connector_to_object fs/notify/mark.c:663 [inline]
fsnotify_add_mark_list fs/notify/mark.c:746 [inline]
fsnotify_add_mark_locked+0x862/0x1a90 fs/notify/mark.c:821
fsnotify_add_inode_mark_locked include/linux/fsnotify_backend.h:888 [inline]
inotify_new_watch fs/notify/inotify/inotify_user.c:620 [inline]
inotify_update_watch fs/notify/inotify/inotify_user.c:647 [inline]
__do_sys_inotify_add_watch fs/notify/inotify/inotify_user.c:781 [inline]
__se_sys_inotify_add_watch+0x129c/0x1760 fs/notify/inotify/inotify_user.c:729
__x64_sys_inotify_add_watch+0x97/0xe0 fs/notify/inotify/inotify_user.c:729
x64_sys_call+0x12b8/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:255
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 8136 Comm: syz.5.527 Not tainted syzkaller #0 PREEMPT(none)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
=====================================================


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[syzbot]

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