syzbot


KCSAN: data-race in shrink_dentry_list / traverse_mounts

Status: auto-closed as invalid on 2022/01/29 17:45
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 337d, last: 337d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in shrink_dentry_list / traverse_mounts

write to 0xffff88814c01bb40 of 4 bytes by task 9160 on cpu 1:
 shrink_dentry_list+0x127/0x300 fs/dcache.c:423
 shrink_dcache_sb+0x188/0x2d0 fs/dcache.c:1296
 reconfigure_super+0x146/0x540 fs/super.c:891
 do_remount fs/namespace.c:2650 [inline]
 path_mount+0x13f9/0x1c40 fs/namespace.c:3310
 do_mount fs/namespace.c:3331 [inline]
 __do_sys_mount fs/namespace.c:3539 [inline]
 __se_sys_mount+0x24b/0x2f0 fs/namespace.c:3516
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3516
 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 0xffff88814c01bb40 of 4 bytes by task 9159 on cpu 0:
 __traverse_mounts fs/namei.c:1346 [inline]
 traverse_mounts+0x338/0x410 fs/namei.c:1385
 handle_mounts fs/namei.c:1494 [inline]
 step_into+0x8d/0xee0 fs/namei.c:1800
 open_last_lookups fs/namei.c:3373 [inline]
 path_openat+0x1059/0x1eb0 fs/namei.c:3556
 do_filp_open+0x105/0x220 fs/namei.c:3586
 do_sys_openat2+0xb5/0x2b0 fs/open.c:1212
 do_sys_open fs/open.c:1228 [inline]
 __do_sys_creat fs/open.c:1304 [inline]
 __se_sys_creat fs/open.c:1298 [inline]
 __x64_sys_creat+0x62/0x80 fs/open.c:1298
 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: 0x00290400 -> 0x00210000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9159 Comm: syz-executor.5 Not tainted 5.16.0-rc6-syzkaller #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 2021/12/25 17:38 upstream b927dfc67d05 6caa12e4 .config log report info KCSAN: data-race in shrink_dentry_list / traverse_mounts
* Struck through repros no longer work on HEAD.