syzbot


KCSAN: data-race in __d_lookup_rcu / __d_rehash (5)

Status: auto-obsoleted due to no activity on 2023/04/05 19:44
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+51e076f12e9009275f7e@syzkaller.appspotmail.com
First crash: 410d, last: 410d
Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __d_lookup_rcu / __d_rehash fs 1 1535d 1535d 0/26 auto-closed as invalid on 2020/04/10 19:18
upstream KCSAN: data-race in __d_lookup_rcu / __d_rehash (2) fs 1 840d 840d 0/26 auto-closed as invalid on 2022/01/31 01:45
upstream KCSAN: data-race in __d_lookup_rcu / __d_rehash (6) ext4 1 146d 145d 0/26 auto-obsoleted due to no activity on 2023/12/25 18:18
upstream KCSAN: data-race in __d_lookup_rcu / __d_rehash (3) ext4 3 725d 702d 0/26 auto-closed as invalid on 2022/05/28 02:05
upstream KCSAN: data-race in __d_lookup_rcu / __d_rehash (4) fs 1 570d 569d 0/26 auto-obsoleted due to no activity on 2022/10/27 12:04
upstream KCSAN: data-race in __d_lookup_rcu / __d_rehash (7) fs 1 45d 45d 0/26 auto-obsoleted due to no activity on 2024/04/05 04:37

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __d_lookup_rcu / __d_rehash

read to 0xffff888142420310 of 8 bytes by task 13653 on cpu 1:
 hlist_bl_unhashed include/linux/list_bl.h:54 [inline]
 d_unhashed include/linux/dcache.h:335 [inline]
 __d_lookup_rcu+0x120/0x290 fs/dcache.c:2400
 lookup_fast+0x8e/0x290 fs/namei.c:1621
 walk_component+0x3f/0x230 fs/namei.c:1990
 lookup_last fs/namei.c:2451 [inline]
 path_lookupat+0x10a/0x2a0 fs/namei.c:2475
 filename_lookup+0x126/0x300 fs/namei.c:2504
 user_path_at_empty+0x42/0x110 fs/namei.c:2877
 user_path_at include/linux/namei.h:57 [inline]
 __do_sys_chdir fs/open.c:551 [inline]
 __se_sys_chdir+0x4f/0x140 fs/open.c:545
 __x64_sys_chdir+0x1f/0x30 fs/open.c:545
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

write to 0xffff888142420310 of 8 bytes by task 2744 on cpu 0:
 hlist_bl_add_head_rcu include/linux/rculist_bl.h:81 [inline]
 __d_rehash+0xc7/0x210 fs/dcache.c:2579
 __d_add+0x367/0x490 fs/dcache.c:2794
 d_add+0x45/0x50 fs/dcache.c:2817
 simple_lookup+0x89/0xa0 fs/libfs.c:76
 __lookup_hash+0xbc/0x180 fs/namei.c:1602
 do_unlinkat+0x14c/0x4f0 fs/namei.c:4302
 __do_sys_unlink fs/namei.c:4364 [inline]
 __se_sys_unlink fs/namei.c:4362 [inline]
 __x64_sys_unlink+0x30/0x40 fs/namei.c:4362
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2744 Comm: udevd Not tainted 6.2.0-syzkaller-12998-gc0927a7a5391-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/16/2023
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/03/01 19:44 upstream c0927a7a5391 ef65e6cb .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in __d_lookup_rcu / __d_rehash
* Struck through repros no longer work on HEAD.