syzbot


KCSAN: data-race in shrink_dentry_list / step_into (7)

Status: moderation: reported on 2024/03/24 15:55
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+fc3368134afd31deb75f@syzkaller.appspotmail.com
First crash: 20d, last: 20d
Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in shrink_dentry_list / step_into (6) fs 1 76d 76d 0/26 auto-obsoleted due to no activity on 2024/03/03 06:03
upstream KCSAN: data-race in shrink_dentry_list / step_into fs 1 900d 900d 0/26 auto-closed as invalid on 2021/12/01 04:11
upstream KCSAN: data-race in shrink_dentry_list / step_into (5) fs 3 194d 233d 0/26 auto-obsoleted due to no activity on 2023/11/06 20:19
upstream KCSAN: data-race in shrink_dentry_list / step_into (2) fs 3 579d 604d 0/26 auto-obsoleted due to no activity on 2022/10/17 16:38
upstream KCSAN: data-race in shrink_dentry_list / step_into (3) fs 1 536d 536d 0/26 auto-obsoleted due to no activity on 2022/11/29 05:37
upstream KCSAN: data-race in shrink_dentry_list / step_into (4) fs 1 474d 474d 0/26 auto-obsoleted due to no activity on 2023/02/06 16:11

Sample crash report:
==================================================================
BUG: KCSAN: data-race in shrink_dentry_list / step_into

read-write to 0xffff8881079ff240 of 4 bytes by task 15786 on cpu 0:
 d_shrink_del fs/dcache.c:449 [inline]
 shrink_dentry_list+0x226/0x3e0 fs/dcache.c:1067
 shrink_dcache_sb+0x165/0x2a0 fs/dcache.c:1195
 reconfigure_super+0x3fe/0x5a0 fs/super.c:1049
 do_remount fs/namespace.c:2892 [inline]
 path_mount+0x96e/0xb30 fs/namespace.c:3671
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3875
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3875
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

read to 0xffff8881079ff240 of 4 bytes by task 14679 on cpu 1:
 __follow_mount_rcu fs/namei.c:1485 [inline]
 handle_mounts fs/namei.c:1536 [inline]
 step_into+0xe7/0x810 fs/namei.c:1842
 open_last_lookups fs/namei.c:3589 [inline]
 path_openat+0x10fc/0x1d80 fs/namei.c:3796
 do_filp_open+0xf7/0x200 fs/namei.c:3826
 do_sys_openat2+0xab/0x120 fs/open.c:1406
 do_sys_open fs/open.c:1421 [inline]
 __do_sys_openat fs/open.c:1437 [inline]
 __se_sys_openat fs/open.c:1432 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1432
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

value changed: 0x00280400 -> 0x00200000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14679 Comm: syz-executor.1 Not tainted 6.8.0-syzkaller-13213-g70293240c5ce #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/24 15:54 upstream 70293240c5ce 0ea90952 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in shrink_dentry_list / step_into
* Struck through repros no longer work on HEAD.