syzbot


possible deadlock in rtnl_lock (6)

Status: upstream: reported C repro on 2019/07/08 19:37
Reported-by: syzbot+174ce29c2308dec5bc68@syzkaller.appspotmail.com
First crash: 1190d, last: 944d

Cause bisection: introduced by (bisect log) :
commit 455302d1c9ae9318660aaeb9748a01ff414c9741
Author: Ilya Maximets <i.maximets@samsung.com>
Date: Fri Jun 28 08:04:07 2019 +0000

  xdp: fix hang while unregistering device bound to xdp socket

Crash: possible deadlock in xsk_notifier (log)
Repro: C syz .config

Fix bisection: failed (bisect log)
similar bugs (9):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-44 possible deadlock in rtnl_lock C 4676 1081d 1273d 0/2 public: reported C repro on 2019/04/12 00:00
upstream possible deadlock in rtnl_lock (5) C 1009 1625d 1654d 6/24 fixed on 2018/05/08 18:30
upstream possible deadlock in rtnl_lock (3) C 3633 1702d 1703d 4/24 fixed on 2018/02/07 13:48
linux-4.19 possible deadlock in rtnl_lock C error 31 754d 1004d 0/1 upstream: reported C repro on 2020/01/06 01:18
upstream possible deadlock in rtnl_lock (4) C 73333 1685d 1702d 4/24 fixed on 2018/02/26 20:04
android-49 possible deadlock in rtnl_lock C 2906 1503d 1655d 0/3 closed as invalid on 2019/04/05 05:43
upstream possible deadlock in rtnl_lock C 15711 1708d 1765d 4/24 fixed on 2018/02/01 04:00
upstream possible deadlock in rtnl_lock (2) C 10369 1704d 1708d 4/24 fixed on 2018/02/04 23:45
linux-4.14 possible deadlock in rtnl_lock C inconclusive 312 863d 1004d 0/1 upstream: reported C repro on 2020/01/06 01:45
Patch testing requests:
Created Duration User Patch Repo Result
2022/09/12 01:27 17m linux-next error
2022/09/06 01:27 18m net OK log

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
5.2.0-next-20190709 #34 Not tainted
------------------------------------------------------
syz-executor186/9066 is trying to acquire lock:
000000007f6e4671 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72

but task is already holding lock:
000000005575bc3b (&xs->mutex){+.+.}, at: xsk_bind+0x16a/0xe80 net/xdp/xsk.c:436

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&xs->mutex){+.+.}:
       __mutex_lock_common kernel/locking/mutex.c:926 [inline]
       __mutex_lock+0xf7/0x1340 kernel/locking/mutex.c:1073
       mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
       xsk_notifier+0x145/0x2a0 net/xdp/xsk.c:764
       notifier_call_chain+0xc2/0x230 kernel/notifier.c:95
       __raw_notifier_call_chain kernel/notifier.c:396 [inline]
       raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:403
       call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1749
       call_netdevice_notifiers_extack net/core/dev.c:1761 [inline]
       call_netdevice_notifiers net/core/dev.c:1775 [inline]
       rollback_registered_many+0x8d5/0xdf0 net/core/dev.c:8204
       rollback_registered+0x109/0x1d0 net/core/dev.c:8246
       unregister_netdevice_queue net/core/dev.c:9293 [inline]
       unregister_netdevice_queue+0x1ee/0x2c0 net/core/dev.c:9286
       br_dev_delete+0x145/0x1a0 net/bridge/br_if.c:383
       br_del_bridge+0xd7/0x120 net/bridge/br_if.c:483
       br_ioctl_deviceless_stub+0x2b0/0x7c0 net/bridge/br_ioctl.c:376
       sock_ioctl+0x44b/0x790 net/socket.c:1144
       vfs_ioctl fs/ioctl.c:46 [inline]
       file_ioctl fs/ioctl.c:509 [inline]
       do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696
       ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
       __do_sys_ioctl fs/ioctl.c:720 [inline]
       __se_sys_ioctl fs/ioctl.c:718 [inline]
       __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
       do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #1 (&net->xdp.lock){+.+.}:
       __mutex_lock_common kernel/locking/mutex.c:926 [inline]
       __mutex_lock+0xf7/0x1340 kernel/locking/mutex.c:1073
       mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
       xsk_notifier+0xa3/0x2a0 net/xdp/xsk.c:760
       notifier_call_chain+0xc2/0x230 kernel/notifier.c:95
       __raw_notifier_call_chain kernel/notifier.c:396 [inline]
       raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:403
       call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1749
       call_netdevice_notifiers_extack net/core/dev.c:1761 [inline]
       call_netdevice_notifiers net/core/dev.c:1775 [inline]
       rollback_registered_many+0x8d5/0xdf0 net/core/dev.c:8204
       rollback_registered+0x109/0x1d0 net/core/dev.c:8246
       unregister_netdevice_queue net/core/dev.c:9293 [inline]
       unregister_netdevice_queue+0x1ee/0x2c0 net/core/dev.c:9286
       br_dev_delete+0x145/0x1a0 net/bridge/br_if.c:383
       br_del_bridge+0xd7/0x120 net/bridge/br_if.c:483
       br_ioctl_deviceless_stub+0x2b0/0x7c0 net/bridge/br_ioctl.c:376
       sock_ioctl+0x44b/0x790 net/socket.c:1144
       vfs_ioctl fs/ioctl.c:46 [inline]
       file_ioctl fs/ioctl.c:509 [inline]
       do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:696
       ksys_ioctl+0xab/0xd0 fs/ioctl.c:713
       __do_sys_ioctl fs/ioctl.c:720 [inline]
       __se_sys_ioctl fs/ioctl.c:718 [inline]
       __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
       do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 (rtnl_mutex){+.+.}:
       check_prev_add kernel/locking/lockdep.c:2405 [inline]
       check_prevs_add kernel/locking/lockdep.c:2507 [inline]
       validate_chain kernel/locking/lockdep.c:2897 [inline]
       __lock_acquire+0x25a9/0x4c30 kernel/locking/lockdep.c:3880
       lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413
       __mutex_lock_common kernel/locking/mutex.c:926 [inline]
       __mutex_lock+0xf7/0x1340 kernel/locking/mutex.c:1073
       mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
       rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72
       xdp_umem_assign_dev+0xbe/0x8f0 net/xdp/xdp_umem.c:96
       xsk_bind+0x4d7/0xe80 net/xdp/xsk.c:502
       __sys_bind+0x239/0x290 net/socket.c:1656
       __do_sys_bind net/socket.c:1667 [inline]
       __se_sys_bind net/socket.c:1665 [inline]
       __x64_sys_bind+0x73/0xb0 net/socket.c:1665
       do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

other info that might help us debug this:

Chain exists of:
  rtnl_mutex --> &net->xdp.lock --> &xs->mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&xs->mutex);
                               lock(&net->xdp.lock);
                               lock(&xs->mutex);
  lock(rtnl_mutex);

 *** DEADLOCK ***

1 lock held by syz-executor186/9066:
 #0: 000000005575bc3b (&xs->mutex){+.+.}, at: xsk_bind+0x16a/0xe80 net/xdp/xsk.c:436

stack backtrace:
CPU: 1 PID: 9066 Comm: syz-executor186 Not tainted 5.2.0-next-20190709 #34
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_circular_bug.cold+0x163/0x172 kernel/locking/lockdep.c:1617
 check_noncircular+0x345/0x3e0 kernel/locking/lockdep.c:1741
 check_prev_add kernel/locking/lockdep.c:2405 [inline]
 check_prevs_add kernel/locking/lockdep.c:2507 [inline]
 validate_chain kernel/locking/lockdep.c:2897 [inline]
 __lock_acquire+0x25a9/0x4c30 kernel/locking/lockdep.c:3880
 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4413
 __mutex_lock_common kernel/locking/mutex.c:926 [inline]
 __mutex_lock+0xf7/0x1340 kernel/locking/mutex.c:1073
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:72
 xdp_umem_assign_dev+0xbe/0x8f0 net/xdp/xdp_umem.c:96
 xsk_bind+0x4d7/0xe80 net/xdp/xsk.c:502
 __sys_bind+0x239/0x290 net/socket.c:1656
 __do_sys_bind net/socket.c:1667 [inline]
 __se_sys_bind net/socket.c:1665 [inline]
 __x64_sys_bind+0x73/0xb0 net/socket.c:1665
 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x447909
Code: e8 cc e7 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fc32958fd98 EFLAGS: 00000246 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 00000000006dcc68 RCX: 0000000000447909
RDX: 0000000000000010 RSI: 0000000020000040 RDI: 0000000000000005
RBP: 00000000006dcc60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dcc6c
R13: 0000003066736362 R14: 0000000000000000 R15: 0000003066736362

Crashes (551):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-linux-next-kasan-gce-root 2019/07/10 12:20 linux-next 4608a726c668 f62e1e85 .config log report syz C
ci-upstream-net-this-kasan-gce 2019/07/07 11:38 net 537de0c8ca2b f62e1e85 .config log report syz C
ci-upstream-kasan-gce-selinux-root 2020/03/03 21:34 upstream 63623fd44972 c88c7b75 .config log report
ci-upstream-kasan-gce-smack-root 2019/07/20 05:21 upstream 3bfe1fc46794 1656845f .config log report
ci-upstream-net-this-kasan-gce 2019/07/19 04:02 net 49d05fe2c9d1 7bb222f7 .config log report
ci-upstream-net-this-kasan-gce 2019/07/04 08:14 net 9d1bc24b52fb 55565fa0 .config log report
ci-upstream-net-kasan-gce 2020/03/06 18:43 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/06 17:34 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/06 09:02 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/06 06:10 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/06 04:52 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/06 03:10 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/05 22:13 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/05 18:57 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/05 17:35 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/05 16:09 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/05 13:02 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/05 11:00 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/05 08:49 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/05 04:29 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/05 02:06 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/05 00:48 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/04 23:55 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/04 22:15 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/04 20:24 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/04 15:14 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/04 13:11 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/04 11:18 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/04 10:01 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/04 07:27 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/04 05:44 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/04 02:55 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/04 01:39 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/03 23:52 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/03 18:38 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/03 17:37 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/03 16:33 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/03 13:49 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/03 12:22 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/03 09:14 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/03 08:49 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/03 06:35 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/03 05:28 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/03 03:22 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/03 00:14 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/02 23:07 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/02 20:55 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/02 19:53 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/02 17:49 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/02 16:02 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-net-kasan-gce 2020/03/02 14:38 net-next 3b3e808cd883 c88c7b75 .config log report
ci-upstream-linux-next-kasan-gce-root 2020/03/06 11:01 linux-next c99b17ac0399 c88c7b75 .config log report
ci-upstream-linux-next-kasan-gce-root 2020/03/03 01:24 linux-next c99b17ac0399 c88c7b75 .config log report
* Struck through repros no longer work on HEAD.