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KCSAN: data-race in d_alloc_parallel / d_set_d_op (12)

Status: moderation: reported on 2025/02/24 22:36
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+679899c675d13c2f2721@syzkaller.appspotmail.com
First crash: 2d23h, last: 2d23h
▶ ▼ Similar bugs (11)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in d_alloc_parallel / d_set_d_op (4) fs 1 1487d 1487d 0/28 auto-closed as invalid on 2021/03/08 01:09
upstream KCSAN: data-race in d_alloc_parallel / d_set_d_op fs 23 1784d 1948d 0/28 auto-closed as invalid on 2020/06/18 13:33
upstream KCSAN: data-race in d_alloc_parallel / d_set_d_op (9) fs 29 187d 391d 0/28 auto-obsoleted due to no activity on 2024/09/27 23:53
upstream KCSAN: data-race in d_alloc_parallel / d_set_d_op (7) fs 4 980d 1036d 0/28 auto-closed as invalid on 2022/07/28 05:03
upstream KCSAN: data-race in d_alloc_parallel / d_set_d_op (2) fs 1 1647d 1647d 0/28 auto-closed as invalid on 2020/09/29 03:57
upstream KCSAN: data-race in d_alloc_parallel / d_set_d_op (10) fs 2 123d 145d 0/28 auto-obsoleted due to no activity on 2024/12/22 11:11
upstream KCSAN: data-race in d_alloc_parallel / d_set_d_op (8) fs 43 429d 446d 0/28 auto-obsoleted due to no activity on 2024/01/30 06:40
upstream KCSAN: data-race in d_alloc_parallel / d_set_d_op (6) fs 3 1073d 1119d 0/28 auto-closed as invalid on 2022/04/26 06:41
upstream KCSAN: data-race in d_alloc_parallel / d_set_d_op (3) fs 2 1551d 1543d 0/28 auto-closed as invalid on 2021/01/03 18:19
upstream KCSAN: data-race in d_alloc_parallel / d_set_d_op (11) fs 1 63d 63d 0/28 auto-obsoleted due to no activity on 2025/02/20 09:31
upstream KCSAN: data-race in d_alloc_parallel / d_set_d_op (5) fs 13 1357d 1446d 0/28 auto-closed as invalid on 2021/07/16 11:19

Sample crash report:
==================================================================
BUG: KCSAN: data-race in d_alloc_parallel / d_set_d_op

read-write to 0xffff888106543180 of 4 bytes by task 4406 on cpu 1:
 d_set_d_op+0xfb/0x1f0 fs/dcache.c:1831
 proc_pident_instantiate+0x164/0x180 fs/proc/base.c:2712
 proc_pident_lookup+0x11d/0x190 fs/proc/base.c:2735
 proc_tgid_base_lookup+0x2b/0x40 fs/proc/base.c:3458
 __lookup_slow+0x18a/0x250 fs/namei.c:1793
 lookup_slow+0x3c/0x60 fs/namei.c:1810
 walk_component fs/namei.c:2114 [inline]
 link_path_walk+0x668/0x830 fs/namei.c:2479
 path_openat+0x1af/0x1fc0 fs/namei.c:3985
 do_filp_open+0x107/0x230 fs/namei.c:4016
 do_sys_openat2+0xab/0x120 fs/open.c:1428
 do_sys_open fs/open.c:1443 [inline]
 __do_sys_openat fs/open.c:1459 [inline]
 __se_sys_openat fs/open.c:1454 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1454
 x64_sys_call+0x2b30/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888106543180 of 4 bytes by task 4405 on cpu 0:
 d_in_lookup include/linux/dcache.h:390 [inline]
 d_wait_lookup fs/dcache.c:2488 [inline]
 d_alloc_parallel+0x5dc/0xc80 fs/dcache.c:2576
 __lookup_slow+0x8d/0x250 fs/namei.c:1778
 lookup_slow+0x3c/0x60 fs/namei.c:1810
 walk_component fs/namei.c:2114 [inline]
 link_path_walk+0x668/0x830 fs/namei.c:2479
 path_openat+0x1af/0x1fc0 fs/namei.c:3985
 do_filp_open+0x107/0x230 fs/namei.c:4016
 do_sys_openat2+0xab/0x120 fs/open.c:1428
 do_sys_open fs/open.c:1443 [inline]
 __do_sys_openat fs/open.c:1459 [inline]
 __se_sys_openat fs/open.c:1454 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1454
 x64_sys_call+0x2b30/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x10000000 -> 0x1000000c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 4405 Comm: syz.0.291 Not tainted 6.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/24 22:35 upstream d082ecbc71e9 d34966d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in d_alloc_parallel / d_set_d_op
* Struck through repros no longer work on HEAD.