syzbot


KCSAN: data-race in __dentry_kill / lookup_fast (6)

Status: auto-closed as invalid on 2021/12/25 02:52
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 311d, last: 311d
similar bugs (5):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __dentry_kill / lookup_fast (5) 12 484d 556d 0/24 auto-closed as invalid on 2021/07/05 09:49
upstream KCSAN: data-race in __dentry_kill / lookup_fast (2) 5 765d 825d 0/24 auto-closed as invalid on 2020/09/27 09:27
upstream KCSAN: data-race in __dentry_kill / lookup_fast 10 847d 941d 0/24 closed as invalid on 2020/06/18 14:24
upstream KCSAN: data-race in __dentry_kill / lookup_fast (4) 3 604d 629d 0/24 auto-closed as invalid on 2021/03/06 20:57
upstream KCSAN: data-race in __dentry_kill / lookup_fast (3) 3 666d 659d 0/24 auto-closed as invalid on 2021/01/03 16:37

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

write to 0xffff8881248f1600 of 4 bytes by task 1906 on cpu 1:
 dentry_unlist fs/dcache.c:522 [inline]
 __dentry_kill+0x147/0x450 fs/dcache.c:578
 dput+0x218/0x430 fs/dcache.c:888
 do_unlinkat+0x2a8/0x540 fs/namei.c:4170
 __do_sys_unlink fs/namei.c:4215 [inline]
 __se_sys_unlink fs/namei.c:4213 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:4213
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881248f1600 of 4 bytes by task 1439 on cpu 0:
 d_revalidate fs/namei.c:853 [inline]
 lookup_fast+0x172/0x360 fs/namei.c:1606
 walk_component+0x6d/0x360 fs/namei.c:1966
 lookup_last fs/namei.c:2425 [inline]
 path_lookupat+0x12d/0x3d0 fs/namei.c:2449
 filename_lookup+0x130/0x310 fs/namei.c:2478
 user_path_at_empty+0x3e/0x110 fs/namei.c:2801
 do_readlinkat+0x97/0x210 fs/stat.c:443
 __do_sys_readlink fs/stat.c:476 [inline]
 __se_sys_readlink fs/stat.c:473 [inline]
 __x64_sys_readlink+0x43/0x50 fs/stat.c:473
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00600008 -> 0x00008008

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1439 Comm: udevd Not tainted 5.16.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2021/11/20 02:47 upstream a90af8f15bdc 4eb20a4e .config log report info KCSAN: data-race in __dentry_kill / lookup_fast
* Struck through repros no longer work on HEAD.