[moderation] [fs?] KCSAN: data-race in d_delete / do_coredump (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d7b8f8e20813 Linux 6.16-rc5
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10c2c28c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=ce48b74bcedce10f
dashboard link: https://syzkaller.appspot.com/bug?extid=1df967c0c31a66d059de
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
CC: [bra...@kernel.org ja...@suse.cz 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/6a4c012a3b93/disk-d7b8f8e2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e3a6050563a6/vmlinux-d7b8f8e2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2bdc7eedebcd/bzImage-d7b8f8e2.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1df967...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in d_delete / do_coredump

write to 0xffff888106be3790 of 8 bytes by task 16799 on cpu 1:
__d_drop fs/dcache.c:575 [inline]
d_delete+0xff/0x180 fs/dcache.c:2461
d_delete_notify+0x32/0x100 include/linux/fsnotify.h:400
vfs_unlink+0x30b/0x420 fs/namei.c:4610
do_unlinkat+0x28e/0x4c0 fs/namei.c:4659
do_coredump+0x12f0/0x27b0 fs/coredump.c:724
get_signal+0xd85/0xf70 kernel/signal.c:3019
arch_do_signal_or_restart+0x96/0x480 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
irqentry_exit_to_user_mode+0x5e/0xa0 kernel/entry/common.c:184
irqentry_exit+0x12/0x50 kernel/entry/common.c:287
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

read to 0xffff888106be3790 of 8 bytes by task 16798 on cpu 0:
hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
d_unhashed include/linux/dcache.h:359 [inline]
do_coredump+0x144a/0x27b0 fs/coredump.c:762
get_signal+0xd85/0xf70 kernel/signal.c:3019
arch_do_signal_or_restart+0x96/0x480 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
irqentry_exit_to_user_mode+0x5e/0xa0 kernel/entry/common.c:184
irqentry_exit+0x12/0x50 kernel/entry/common.c:287
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

value changed: 0xffff88823741c188 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 16798 Comm: syz.9.3814 Tainted: G W 6.16.0-rc5-syzkaller #0 PREEMPT(voluntary)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================


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[syzbot]

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