syzbot


KCSAN: data-race in d_delete / lookup_fast (5)

Status: auto-closed as invalid on 2021/09/28 20:03
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 474d, last: 461d
similar bugs (4):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in d_delete / lookup_fast (2) 2 751d 721d 0/24 auto-closed as invalid on 2020/12/21 11:52
upstream KCSAN: data-race in d_delete / lookup_fast (4) 12 516d 592d 0/24 auto-closed as invalid on 2021/08/05 10:35
upstream KCSAN: data-race in d_delete / lookup_fast 33 1034d 1131d 0/24 auto-closed as invalid on 2020/04/08 11:57
upstream KCSAN: data-race in d_delete / lookup_fast (3) 1 673d 673d 0/24 auto-closed as invalid on 2021/02/28 15:17

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

write to 0xffff888106f13300 of 4 bytes by task 24711 on cpu 1:
 d_delete+0x6e/0xe0 fs/dcache.c:2504
 vfs_unlink+0x3d8/0x400 fs/namei.c:4049
 do_unlinkat+0x238/0x4f0 fs/namei.c:4102
 __do_sys_unlink fs/namei.c:4149 [inline]
 __se_sys_unlink fs/namei.c:4147 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:4147
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888106f13300 of 4 bytes by task 1125 on cpu 0:
 d_revalidate fs/namei.c:842 [inline]
 lookup_fast+0x15f/0x350 fs/namei.c:1595
 walk_component+0x5c/0x350 fs/namei.c:1955
 lookup_last fs/namei.c:2414 [inline]
 path_lookupat+0x12d/0x3d0 fs/namei.c:2438
 filename_lookup+0x118/0x3b0 fs/namei.c:2467
 user_path_at_empty+0x3b/0x50 fs/namei.c:2747
 do_readlinkat+0x87/0x200 fs/stat.c:425
 __do_sys_readlink fs/stat.c:458 [inline]
 __se_sys_readlink fs/stat.c:455 [inline]
 __x64_sys_readlink+0x43/0x50 fs/stat.c:455
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00600108 -> 0x00008008

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1125 Comm: systemd-udevd Not tainted 5.14.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2021/08/24 20:03 upstream 6e764bcd1cf7 b599f2fc .config log report info KCSAN: data-race in d_delete / lookup_fast
ci2-upstream-kcsan-gce 2021/08/19 21:51 upstream f87d64319e6f e2da378b .config log report info KCSAN: data-race in d_delete / lookup_fast
ci2-upstream-kcsan-gce 2021/08/11 14:27 upstream 761c6d7ec820 6972b106 .config log report info KCSAN: data-race in d_delete / lookup_fast
* Struck through repros no longer work on HEAD.