syzbot


KCSAN: data-race in __dentry_kill / lookup_fast (2)

Status: auto-closed as invalid on 2020/09/27 09:27
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 828d, last: 768d
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 487d 559d 0/24 auto-closed as invalid on 2021/07/05 09:49
upstream KCSAN: data-race in __dentry_kill / lookup_fast 10 850d 944d 0/24 closed as invalid on 2020/06/18 14:24
upstream KCSAN: data-race in __dentry_kill / lookup_fast (6) 1 314d 314d 0/24 auto-closed as invalid on 2021/12/25 02:52
upstream KCSAN: data-race in __dentry_kill / lookup_fast (4) 3 607d 632d 0/24 auto-closed as invalid on 2021/03/06 20:57
upstream KCSAN: data-race in __dentry_kill / lookup_fast (3) 3 669d 662d 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 0xffff8880973b9840 of 4 bytes by task 22763 on cpu 1:
 dentry_unlist fs/dcache.c:519 [inline]
 __dentry_kill+0x147/0x450 fs/dcache.c:575
 dentry_kill fs/dcache.c:692 [inline]
 dput+0x208/0x420 fs/dcache.c:878
 do_unlinkat+0x298/0x4d0 fs/namei.c:3898
 __do_sys_unlink fs/namei.c:3942 [inline]
 __se_sys_unlink fs/namei.c:3940 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:3940
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880973b9840 of 4 bytes by task 5072 on cpu 0:
 d_revalidate fs/namei.c:767 [inline]
 lookup_fast+0x15f/0x370 fs/namei.c:1493
 walk_component+0x5c/0x350 fs/namei.c:1856
 lookup_last fs/namei.c:2309 [inline]
 path_lookupat+0x12d/0x560 fs/namei.c:2333
 filename_lookup+0xf2/0x380 fs/namei.c:2366
 user_path_at_empty+0x3b/0x50 fs/namei.c:2646
 do_readlinkat+0x87/0x200 fs/stat.c:419
 __do_sys_readlink fs/stat.c:452 [inline]
 __se_sys_readlink fs/stat.c:449 [inline]
 __x64_sys_readlink+0x43/0x50 fs/stat.c:449
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5072 Comm: systemd-udevd Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (5):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2020/08/23 09:21 upstream c3d8f220d012 1da71ab0 .config log report
ci2-upstream-kcsan-gce 2020/08/04 01:31 upstream e4cbce4d1317 96dd3623 .config log report
ci2-upstream-kcsan-gce 2020/07/14 23:13 upstream e9919e11e219 ada108d0 .config log report
ci2-upstream-kcsan-gce 2020/06/24 15:00 upstream 3e08a95294a4 41694dbf .config log report
ci2-upstream-kcsan-gce 2020/06/24 12:28 upstream 3e08a95294a4 41694dbf .config log report
* Struck through repros no longer work on HEAD.