syzbot


KCSAN: data-race in __dentry_kill / step_into (3)

Status: auto-closed as invalid on 2022/01/30 10:25
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 399d, last: 341d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __dentry_kill / step_into 1 784d 784d 0/24 auto-closed as invalid on 2020/11/14 02:21
upstream KCSAN: data-race in __dentry_kill / step_into (4) 1 279d 279d 0/24 auto-closed as invalid on 2022/04/03 02:19
upstream KCSAN: data-race in __dentry_kill / step_into (2) 3 539d 577d 0/24 auto-closed as invalid on 2021/07/16 10:59

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

write to 0xffff888141f706c0 of 4 bytes by task 18705 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 0xffff888141f706c0 of 4 bytes by task 1438 on cpu 0:
 __follow_mount_rcu fs/namei.c:1429 [inline]
 handle_mounts fs/namei.c:1486 [inline]
 step_into+0x103/0xee0 fs/namei.c:1800
 walk_component+0x1a1/0x360 fs/namei.c:1976
 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: 1438 Comm: udevd Not tainted 5.16.0-rc6-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 2021/12/26 10:18 upstream 438645193e59 e4f103c4 .config log report info KCSAN: data-race in __dentry_kill / step_into
ci2-upstream-kcsan-gce 2021/12/19 05:45 upstream 3f667b5d4053 44068e19 .config log report info KCSAN: data-race in __dentry_kill / step_into
ci2-upstream-kcsan-gce 2021/11/25 19:59 upstream b501b85957de 63eeac02 .config log report info KCSAN: data-race in __dentry_kill / step_into
ci2-upstream-kcsan-gce 2021/11/08 12:19 upstream 6b75d88fa81b d29682f1 .config log report info KCSAN: data-race in __dentry_kill / step_into
ci2-upstream-kcsan-gce 2021/10/30 00:09 upstream a379fbbcb88b 2353a3ec .config log report info KCSAN: data-race in __dentry_kill / step_into
* Struck through repros no longer work on HEAD.