syzbot


KCSAN: data-race in lookup_fast / vfs_rename

Status: auto-closed as invalid on 2020/09/04 03:18
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 795d, last: 791d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in lookup_fast / vfs_rename (4) 1 189d 189d 0/24 auto-closed as invalid on 2022/04/28 23:59
upstream KCSAN: data-race in lookup_fast / vfs_rename (3) 1 314d 314d 0/24 auto-closed as invalid on 2021/12/24 12:08
upstream KCSAN: data-race in lookup_fast / vfs_rename (2) 1 593d 593d 0/24 auto-closed as invalid on 2021/03/20 21:45

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

write to 0xffff88811d8d06c0 of 4 bytes by task 13509 on cpu 1:
 dont_mount include/linux/dcache.h:354 [inline]
 vfs_rename+0x970/0xba0 fs/namei.c:4313
 do_renameat2+0x554/0x930 fs/namei.c:4450
 __do_sys_rename fs/namei.c:4496 [inline]
 __se_sys_rename fs/namei.c:4494 [inline]
 __x64_sys_rename+0x3a/0x40 fs/namei.c:4494
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88811d8d06c0 of 4 bytes by task 5047 on cpu 0:
 d_revalidate fs/namei.c:767 [inline]
 lookup_fast+0x15f/0x370 fs/namei.c:1493
 open_last_lookups fs/namei.c:3135 [inline]
 path_openat+0x467/0x20e0 fs/namei.c:3357
 do_filp_open+0xbd/0x1d0 fs/namei.c:3387
 do_sys_openat2+0x33c/0x4a0 fs/open.c:1179
 do_sys_open fs/open.c:1195 [inline]
 ksys_open include/linux/syscalls.h:1388 [inline]
 __do_sys_open fs/open.c:1201 [inline]
 __se_sys_open fs/open.c:1199 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1199
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5047 Comm: systemd-udevd Not tainted 5.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2020/07/31 03:16 upstream e2c46b5762c6 8df85ed9 .config log report
ci2-upstream-kcsan-gce 2020/07/27 06:31 upstream 92ed30191993 cb93dc6a .config log report
* Struck through repros no longer work on HEAD.