syzbot


KCSAN: data-race in lookup_fast / shrink_dentry_list (11)

Status: moderation: reported on 2024/04/18 20:34
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+872f97f9542a3dae89c8@syzkaller.appspotmail.com
First crash: 36d, last: 32d
Similar bugs (10)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in lookup_fast / shrink_dentry_list (9) fs 1 373d 373d 0/26 auto-obsoleted due to no activity on 2023/06/21 20:05
upstream KCSAN: data-race in lookup_fast / shrink_dentry_list (6) fs 1 680d 680d 0/26 auto-closed as invalid on 2022/08/18 12:57
upstream KCSAN: data-race in lookup_fast / shrink_dentry_list (4) fs 1 1151d 1151d 0/26 auto-closed as invalid on 2021/05/04 09:30
upstream KCSAN: data-race in lookup_fast / shrink_dentry_list (10) fs 2 124d 126d 0/26 auto-obsoleted due to no activity on 2024/02/25 15:26
upstream KCSAN: data-race in lookup_fast / shrink_dentry_list (2) fs 1 1301d 1301d 0/26 auto-closed as invalid on 2020/12/05 11:21
upstream KCSAN: data-race in lookup_fast / shrink_dentry_list (3) fs 2 1208d 1238d 0/26 auto-closed as invalid on 2021/03/08 10:39
upstream KCSAN: data-race in lookup_fast / shrink_dentry_list (8) fs 1 436d 436d 0/26 auto-obsoleted due to no activity on 2023/04/27 01:35
upstream KCSAN: data-race in lookup_fast / shrink_dentry_list (7) fs 1 643d 643d 0/26 auto-closed as invalid on 2022/09/24 23:48
upstream KCSAN: data-race in lookup_fast / shrink_dentry_list (5) fs 1 1001d 1001d 0/26 auto-closed as invalid on 2021/10/01 10:16
upstream KCSAN: data-race in lookup_fast / shrink_dentry_list fs 3 1359d 1385d 0/26 auto-closed as invalid on 2020/10/08 14:19

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

read-write to 0xffff888108061f00 of 4 bytes by task 23990 on cpu 0:
 d_shrink_del fs/dcache.c:449 [inline]
 shrink_dentry_list+0x19f/0x3e0 fs/dcache.c:1074
 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
 x64_sys_call+0x2591/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888108061f00 of 4 bytes by task 22979 on cpu 1:
 d_revalidate fs/namei.c:860 [inline]
 lookup_fast+0xd9/0x2a0 fs/namei.c:1641
 walk_component+0x3f/0x230 fs/namei.c:2000
 lookup_last fs/namei.c:2461 [inline]
 path_lookupat+0x10a/0x2b0 fs/namei.c:2485
 filename_lookup+0x127/0x300 fs/namei.c:2514
 vfs_statx+0xa2/0x320 fs/stat.c:244
 vfs_fstatat+0xcd/0x100 fs/stat.c:304
 __do_sys_newfstatat fs/stat.c:468 [inline]
 __se_sys_newfstatat+0x58/0x260 fs/stat.c:462
 __x64_sys_newfstatat+0x55/0x70 fs/stat.c:462
 x64_sys_call+0x25ff/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:263
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00680440 -> 0x00008040

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 22979 Comm: syz-executor.3 Tainted: G        W          6.9.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/22 20:03 upstream ed30a4a51bb1 36c961ad .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in lookup_fast / shrink_dentry_list
2024/04/18 20:33 upstream 8cd26fd90c1a af24b050 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in lookup_fast / shrink_dentry_list
* Struck through repros no longer work on HEAD.