[moderation] [fs?] KCSAN: data-race in __dentry_kill / shrink_dentry_list (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7ed2632ec7d7 drm/ttm: fix ttm pool initialization for no-d..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15eecd7de80000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1bd33f45956bbc2
dashboard link: https://syzkaller.appspot.com/bug?extid=7be3ff91a90b52fc32b9
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [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/ff6facc21dca/disk-7ed2632e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/be6ef58407dd/vmlinux-7ed2632e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f18ed26c2f87/bzImage-7ed2632e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7be3ff...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __dentry_kill / shrink_dentry_list

read-write to 0xffff88813eaa59c0 of 4 bytes by task 3151 on cpu 1:
d_shrink_del fs/dcache.c:449 [inline]
shrink_dentry_list+0x19f/0x3d0 fs/dcache.c:1074
shrink_dcache_parent+0x43/0x1b0
d_invalidate+0xa6/0x1c0 fs/dcache.c:1592
proc_invalidate_siblings_dcache+0x1db/0x2b0 fs/proc/inode.c:145
proc_flush_pid+0x1d/0x20 fs/proc/base.c:3421
release_task+0xae6/0xc20 kernel/exit.c:282
wait_task_zombie kernel/exit.c:1186 [inline]
wait_consider_task+0x1172/0x1680 kernel/exit.c:1413
do_wait_thread kernel/exit.c:1476 [inline]
__do_wait+0xff/0x4f0 kernel/exit.c:1594
do_wait+0xae/0x270 kernel/exit.c:1628
kernel_wait4+0x15f/0x1c0 kernel/exit.c:1787
__do_sys_wait4 kernel/exit.c:1815 [inline]
__se_sys_wait4 kernel/exit.c:1811 [inline]
__x64_sys_wait4+0x94/0x120 kernel/exit.c:1811
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff88813eaa59c0 of 4 bytes by task 29483 on cpu 0:
dentry_unlist fs/dcache.c:573 [inline]
__dentry_kill+0x29d/0x4a0 fs/dcache.c:617
dput+0x54/0xc0 fs/dcache.c:845
proc_invalidate_siblings_dcache+0x1e3/0x2b0 fs/proc/inode.c:146
proc_flush_pid+0x1d/0x20 fs/proc/base.c:3421
release_task+0xb8d/0xc20 kernel/exit.c:282
exit_notify kernel/exit.c:767 [inline]
do_exit+0xf09/0x16d0 kernel/exit.c:891
do_group_exit+0x101/0x150 kernel/exit.c:1020
get_signal+0xf4e/0x10a0 kernel/signal.c:2893
arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline]
syscall_exit_to_user_mode+0x57/0x130 kernel/entry/common.c:212
do_syscall_64+0x65/0x120 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0048040c -> 0x0000000c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 29483 Comm: syz-executor.2 Not tainted 6.8.0-rc1-syzkaller-00026-g7ed2632ec7d7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================


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