syzbot


KCSAN: data-race in d_lru_add / lookup_fast (3)

Status: auto-closed as invalid on 2022/07/14 18:04
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 171d, last: 171d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in d_lru_add / lookup_fast (2) 2 1057d 1104d 0/24 auto-closed as invalid on 2020/03/16 05:36
upstream KCSAN: data-race in d_lru_add / lookup_fast 1 1117d 1117d 0/24 closed as invalid on 2019/11/19 13:54

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

write to 0xffff888138410b40 of 4 bytes by task 9672 on cpu 1:
 d_lru_add+0x45/0xe0 fs/dcache.c:427
 retain_dentry+0x153/0x190 fs/dcache.c:685
 dput+0x10e/0x1f0 fs/dcache.c:908
 done_path_create fs/namei.c:3795 [inline]
 do_mkdirat+0x10f/0x280 fs/namei.c:4004
 __do_sys_mkdir fs/namei.c:4021 [inline]
 __se_sys_mkdir fs/namei.c:4019 [inline]
 __x64_sys_mkdir+0x40/0x50 fs/namei.c:4019
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

read to 0xffff888138410b40 of 4 bytes by task 9673 on cpu 0:
 d_revalidate fs/namei.c:847 [inline]
 lookup_fast+0x172/0x360 fs/namei.c:1650
 walk_component+0x6b/0x280 fs/namei.c:2010
 lookup_last fs/namei.c:2469 [inline]
 path_lookupat+0x11d/0x2b0 fs/namei.c:2493
 filename_lookup+0x130/0x310 fs/namei.c:2522
 user_path_at_empty+0x3e/0x110 fs/namei.c:2895
 user_path_at include/linux/namei.h:57 [inline]
 do_mount fs/namespace.c:3380 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x24d/0x2d0 fs/namespace.c:3568
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

value changed: 0x00200000 -> 0x00280040

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9673 Comm: syz-executor.1 Not tainted 5.19.0-rc1-syzkaller-00024-g6bfb56e93bce-dirty #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 2022/06/09 17:55 upstream 6bfb56e93bce 0d5abf15 .config log report info KCSAN: data-race in d_lru_add / lookup_fast
* Struck through repros no longer work on HEAD.