[moderation] [ext4?] KCSAN: data-race in __d_rehash / retain_dentry (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 2cf4f94d8e86 Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16d3872ae80000
kernel config: https://syzkaller.appspot.com/x/.config?x=989a728d0f884055
dashboard link: https://syzkaller.appspot.com/bug?extid=da55de8d64550a56f4f4
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [adilger...@dilger.ca linux...@vger.kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org ty...@mit.edu]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/eab343f2d1a0/disk-2cf4f94d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3222d147aacc/vmlinux-2cf4f94d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/81f4502c659f/bzImage-2cf4f94d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+da55de...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __d_rehash / retain_dentry

write to 0xffff888129e0a850 of 8 bytes by task 25212 on cpu 0:
hlist_bl_add_head_rcu include/linux/rculist_bl.h:81 [inline]
__d_rehash+0xc4/0x220 fs/dcache.c:2578
__d_add+0x36d/0x4a0 fs/dcache.c:2793
d_splice_alias+0xd6/0x270 fs/dcache.c:3181
ext4_lookup+0x199/0x390 fs/ext4/namei.c:1883
lookup_one_qstr_excl+0xc0/0x180 fs/namei.c:1609
filename_create+0x14d/0x2b0 fs/namei.c:3876
do_symlinkat+0x84/0x340 fs/namei.c:4483
__do_sys_symlinkat fs/namei.c:4506 [inline]
__se_sys_symlinkat fs/namei.c:4503 [inline]
__x64_sys_symlinkat+0x62/0x70 fs/namei.c:4503
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888129e0a850 of 8 bytes by task 25214 on cpu 1:
hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
d_unhashed include/linux/dcache.h:336 [inline]
retain_dentry+0x40/0x190 fs/dcache.c:668
dput+0x108/0x1f0 fs/dcache.c:908
__fput+0x41d/0x630 fs/file_table.c:402
__fput_sync+0x44/0x50 fs/file_table.c:475
__do_sys_close fs/open.c:1587 [inline]
__se_sys_close+0xfa/0x1a0 fs/open.c:1572
__x64_sys_close+0x1f/0x30 fs/open.c:1572
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0xffff888237a3dca8 -> 0xffff88812358d308

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 25214 Comm: syz-executor.4 Not tainted 6.7.0-rc6-syzkaller-00010-g2cf4f94d8e86 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================


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[syzbot]

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