syzbot


KCSAN: data-race in l2tp_tunnel_del_work / sk_common_release (3)

Status: auto-closed as invalid on 2022/08/23 20:42
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 139d, last: 139d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in l2tp_tunnel_del_work / sk_common_release (2) 2 687d 719d 0/24 auto-closed as invalid on 2021/02/22 11:54
upstream KCSAN: data-race in l2tp_tunnel_del_work / sk_common_release 22 1035d 1138d 0/24 auto-closed as invalid on 2020/04/15 13:52

Sample crash report:
==================================================================
BUG: KCSAN: data-race in l2tp_tunnel_del_work / sk_common_release

write to 0xffff88812ca69cf0 of 8 bytes by task 4913 on cpu 0:
 sk_set_socket include/net/sock.h:2013 [inline]
 sock_orphan include/net/sock.h:2032 [inline]
 sk_common_release+0x99/0x210 net/core/sock.c:3612
 udp_lib_close+0x11/0x20 include/net/udp.h:188
 inet_release+0xc6/0xe0 net/ipv4/af_inet.c:428
 inet6_release+0x3a/0x50 net/ipv6/af_inet6.c:481
 __sock_release net/socket.c:650 [inline]
 sock_close+0x6c/0x150 net/socket.c:1365
 __fput+0x292/0x510 fs/file_table.c:317
 ____fput+0x11/0x20 fs/file_table.c:350
 task_work_run+0x8e/0x110 kernel/task_work.c:177
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x124/0x130 kernel/entry/common.c:169
 exit_to_user_mode_prepare kernel/entry/common.c:201 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x6a/0x90 kernel/entry/common.c:294
 do_syscall_64+0x37/0x70 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88812ca69cf0 of 8 bytes by task 1847 on cpu 1:
 l2tp_tunnel_del_work+0x3a/0x380 net/l2tp/l2tp_core.c:1234
 process_one_work+0x3d3/0x720 kernel/workqueue.c:2289
 worker_thread+0x618/0xa70 kernel/workqueue.c:2436
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

value changed: 0xffff888127616900 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1847 Comm: kworker/u4:5 Not tainted 5.19.0-rc7-syzkaller-00005-gca85855bdcae-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
Workqueue: l2tp l2tp_tunnel_del_work
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/07/19 20:41 upstream ca85855bdcae 775344bc .config log report info KCSAN: data-race in l2tp_tunnel_del_work / sk_common_release
* Struck through repros no longer work on HEAD.