possible deadlock in vmci_qp_broker

possible deadlock in vmci_qp_broker_detach
Status: upstream: reported C repro on 2021/03/26 01:19
Reported-by: syzbot+44e40ac2cfe68e8ce207@syzkaller.appspotmail.com
First crash: 124d, last: 21d

Cause bisection: introduced by (bisect log) [no-op commit]:
commit 2dd209f00fc5a1caafa493066c7cd692fd2fd57c
Author: Bart Van Assche <bvanassche@acm.org>
Date: Tue Mar 10 04:26:16 2020 +0000

blk-mq: Fix a comment in include/linux/blk-mq.h

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

similar bugs (1):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
linux-4.19	possible deadlock in vmci_qp_broker_detach	C			6	15d	207d	0/1	upstream: reported C repro on 2020/12/28 17:12

Patch testing requests:
Created	Duration	User	Patch	Repo	Result
2021/06/30 22:00	19m	paskripkin@gmail.com	patch	upstream	report log
2021/06/30 21:36	19m	paskripkin@gmail.com	patch	upstream	report log

Sample crash report:

============================================
WARNING: possible recursive locking detected
5.13.0-rc2-next-20210518-syzkaller #0 Not tainted
--------------------------------------------
syz-executor723/9333 is trying to acquire lock:
ffffffff8cc8b5f8 (qp_broker_list.mutex){+.+.}-{3:3}, at: vmci_qp_broker_detach+0x147/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2093

but task is already holding lock:
ffffffff8cc8b5f8 (qp_broker_list.mutex){+.+.}-{3:3}, at: vmci_qp_broker_detach+0x147/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2093

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(qp_broker_list.mutex);
  lock(qp_broker_list.mutex);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

1 lock held by syz-executor723/9333:
 #0: ffffffff8cc8b5f8 (qp_broker_list.mutex){+.+.}-{3:3}, at: vmci_qp_broker_detach+0x147/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2093

stack backtrace:
CPU: 0 PID: 9333 Comm: syz-executor723 Not tainted 5.13.0-rc2-next-20210518-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x13e/0x1d6 lib/dump_stack.c:129
 print_deadlock_bug kernel/locking/lockdep.c:2831 [inline]
 check_deadlock kernel/locking/lockdep.c:2874 [inline]
 validate_chain kernel/locking/lockdep.c:3663 [inline]
 __lock_acquire.cold+0x22f/0x3b4 kernel/locking/lockdep.c:4902
 lock_acquire kernel/locking/lockdep.c:5512 [inline]
 lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5477
 __mutex_lock_common kernel/locking/mutex.c:949 [inline]
 __mutex_lock+0x139/0x1120 kernel/locking/mutex.c:1096
 vmci_qp_broker_detach+0x147/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2093
 ctx_free_ctx+0x4cc/0xd30 drivers/misc/vmw_vmci/vmci_context.c:444
 kref_put include/linux/kref.h:65 [inline]
 vmci_ctx_put drivers/misc/vmw_vmci/vmci_context.c:497 [inline]
 vmci_ctx_enqueue_datagram+0x4dc/0x620 drivers/misc/vmw_vmci/vmci_context.c:360
 dg_dispatch_as_host drivers/misc/vmw_vmci/vmci_datagram.c:275 [inline]
 vmci_datagram_dispatch+0x39b/0xb50 drivers/misc/vmw_vmci/vmci_datagram.c:339
 qp_notify_peer+0x182/0x260 drivers/misc/vmw_vmci/vmci_queue_pair.c:1479
 vmci_qp_broker_detach+0xa09/0x11b0 drivers/misc/vmw_vmci/vmci_queue_pair.c:2186
 ctx_free_ctx+0x4cc/0xd30 drivers/misc/vmw_vmci/vmci_context.c:444
 kref_put include/linux/kref.h:65 [inline]
 vmci_ctx_put drivers/misc/vmw_vmci/vmci_context.c:497 [inline]
 vmci_ctx_destroy+0x169/0x1d0 drivers/misc/vmw_vmci/vmci_context.c:195
 vmci_host_close+0x116/0x1a0 drivers/misc/vmw_vmci/vmci_host.c:143
 __fput+0x288/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x26f/0x280 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301
 do_syscall_64+0x3e/0xb0 arch/x86/entry/common.c:57
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x445ac9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 00 00 90 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe38cec92f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000124
RAX: 0000000000000005 RBX: 00000000004ca420 RCX: 0000000000445ac9
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004
RBP: 00000000004ca42c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000049a074
R13: 65732f636f72702f R14: 636d762f7665642f R15: 00000000004ca428

Crashes (18):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci-upstream-linux-next-kasan-gce-root	2021/06/30 17:21	linux-next	a1f92694393a	84fd4c77	.config	log	report	syz	C		possible deadlock in vmci_qp_broker_detach
ci-upstream-kasan-gce	2021/07/03 06:42	upstream	3dbdb38e2869	55aa55c2	.config	log	report	syz			possible deadlock in vmci_qp_broker_detach
ci-upstream-kasan-gce	2021/04/14 15:29	upstream	50987beca096	3134b37f	.config	log	report	syz			possible deadlock in vmci_qp_broker_detach
ci-upstream-kasan-gce-smack-root	2021/04/12 17:28	upstream	d434405aaab7	bfeda1b1	.config	log	report	syz			possible deadlock in vmci_qp_broker_detach
ci-upstream-linux-next-kasan-gce-root	2021/05/18 09:33	linux-next	cd557f1c605f	a343ba6b	.config	log	report	syz			possible deadlock in vmci_qp_broker_detach
ci-upstream-kasan-gce-selinux-root	2021/06/29 15:48	upstream	233a806b00e3	9d2ab5df	.config	log	report			info	possible deadlock in vmci_qp_broker_detach
ci-upstream-kasan-gce-selinux-root	2021/06/10 03:04	upstream	cd1245d75ce9	1ba81399	.config	log	report			info	possible deadlock in vmci_qp_broker_detach
ci-upstream-kasan-gce-selinux-root	2021/05/19 22:37	upstream	293837b9ac8d	a343ba6b	.config	log	report			info	possible deadlock in vmci_qp_broker_detach
ci-upstream-kasan-gce	2021/05/17 08:59	upstream	d07f6ca923ea	a2eb125d	.config	log	report			info	possible deadlock in vmci_qp_broker_detach
ci-upstream-kasan-gce-selinux-root	2021/04/24 01:59	upstream	e77a830c8297	17f0b706	.config	log	report			info	possible deadlock in vmci_qp_broker_detach
ci-upstream-kasan-gce	2021/04/14 11:37	upstream	50987beca096	3134b37f	.config	log	report			info	possible deadlock in vmci_qp_broker_detach
ci-upstream-kasan-gce-smack-root	2021/04/12 16:01	upstream	d434405aaab7	bfeda1b1	.config	log	report			info	possible deadlock in vmci_qp_broker_detach
ci-upstream-kasan-gce	2021/03/31 10:37	upstream	2bb25b3a748a	6a81331a	.config	log	report			info	possible deadlock in vmci_qp_broker_detach
ci-upstream-kasan-gce	2021/03/22 01:14	upstream	5ee96fa9dd78	bea32f74	.config	log	report			info	possible deadlock in vmci_qp_broker_detach
ci-qemu-upstream-386	2021/06/15 21:38	upstream	94f0b2d4a1d0	990d3cbe	.config	log	report			info	possible deadlock in vmci_qp_broker_detach
ci-qemu-upstream-386	2021/05/14 20:08	upstream	bd3c9cdb21a2	8bdd5343	.config	log	report			info	possible deadlock in vmci_qp_broker_detach
ci-upstream-linux-next-kasan-gce-root	2021/06/30 09:34	linux-next	a1f92694393a	84fd4c77	.config	log	report			info	possible deadlock in vmci_qp_broker_detach
ci-upstream-linux-next-kasan-gce-root	2021/05/17 21:55	linux-next	cd557f1c605f	a343ba6b	.config	log	report			info	possible deadlock in vmci_qp_broker_detach