block nbd4: Receive control failed (result -22) block nbd4: shutting down sockets ============================================ WARNING: possible recursive locking detected 4.19.80 #0 Not tainted -------------------------------------------- kworker/u5:1/8224 is trying to acquire lock: 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: flush_workqueue+0xf7/0x14b0 kernel/workqueue.c:2652 but task is already holding lock: 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: process_one_work+0x87e/0x1750 kernel/workqueue.c:2124 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock((wq_completion)"knbd%d-recv"nbd->index); lock((wq_completion)"knbd%d-recv"nbd->index); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by kworker/u5:1/8224: #0: 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000007b22e084 ((wq_completion)"knbd%d-recv"nbd->index){+.+.}, at: process_one_work+0x87e/0x1750 kernel/workqueue.c:2124 #1: 00000000459f9595 ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x8b4/0x1750 kernel/workqueue.c:2128 #2: 000000007f0bb026 (&nbd->config_lock){+.+.}, at: refcount_dec_and_mutex_lock lib/refcount.c:311 [inline] #2: 000000007f0bb026 (&nbd->config_lock){+.+.}, at: refcount_dec_and_mutex_lock+0x56/0x90 lib/refcount.c:306 stack backtrace: CPU: 1 PID: 8224 Comm: kworker/u5:1 Not tainted 4.19.80 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: knbd4-recv recv_work Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_deadlock_bug kernel/locking/lockdep.c:1759 [inline] check_deadlock kernel/locking/lockdep.c:1803 [inline] validate_chain kernel/locking/lockdep.c:2399 [inline] __lock_acquire.cold+0x20f/0x4a7 kernel/locking/lockdep.c:3411 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:3903 flush_workqueue+0x126/0x14b0 kernel/workqueue.c:2655 drain_workqueue+0x1b4/0x470 kernel/workqueue.c:2820 destroy_workqueue+0x21/0x6b0 kernel/workqueue.c:4158 nbd_config_put+0x3cf/0x860 drivers/block/nbd.c:1132 recv_work+0x19b/0x200 drivers/block/nbd.c:740 process_one_work+0x989/0x1750 kernel/workqueue.c:2153 worker_thread+0x98/0xe40 kernel/workqueue.c:2296 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 kobject: 'loop1' (00000000ed1e4b23): kobject_uevent_env kobject: 'loop1' (00000000ed1e4b23): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'loop2' (0000000096c35d3e): kobject_uevent_env kobject: 'loop2' (0000000096c35d3e): fill_kobj_path: path = '/devices/virtual/block/loop2' netlink: 'syz-executor.3': attribute type 2 has an invalid length. kobject: 'loop0' (0000000075bee5ea): kobject_uevent_env kobject: 'loop0' (0000000075bee5ea): fill_kobj_path: path = '/devices/virtual/block/loop0' overlayfs: unrecognized mount option ";Ì·-†u¬¸p" or missing value nf_conntrack: default automatic helper assignment has been turned off for security reasons and CT-based firewall rule not found. Use the iptables CT target to attach helpers instead. TCP: request_sock_TCP: Possible SYN flooding on port 20000. Sending cookies. Check SNMP counters. kobject: 'loop2' (0000000096c35d3e): kobject_uevent_env kobject: 'loop2' (0000000096c35d3e): fill_kobj_path: path = '/devices/virtual/block/loop2' audit: type=1804 audit(1572238871.517:56): pid=8262 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir978770137/syzkaller.b7Owe0/19/bus" dev="sda1" ino=16606 res=1 overlayfs: unrecognized mount option ";Ì·-†u¬¸p" or missing value kobject: 'loop3' (000000009f250bac): kobject_uevent_env kobject: 'loop3' (000000009f250bac): fill_kobj_path: path = '/devices/virtual/block/loop3' kobject: 'loop5' (000000000a7cc420): kobject_uevent_env kobject: 'loop5' (000000000a7cc420): fill_kobj_path: path = '/devices/virtual/block/loop5' netlink: 'syz-executor.3': attribute type 2 has an invalid length. kobject: 'loop2' (0000000096c35d3e): kobject_uevent_env TCP: request_sock_TCP: Possible SYN flooding on port 20000. Sending cookies. Check SNMP counters. kobject: 'loop2' (0000000096c35d3e): fill_kobj_path: path = '/devices/virtual/block/loop2' kobject: 'loop0' (0000000075bee5ea): kobject_uevent_env kobject: 'loop0' (0000000075bee5ea): fill_kobj_path: path = '/devices/virtual/block/loop0' overlayfs: unrecognized mount option ";Ì·-†u¬¸p" or missing value kobject: 'loop1' (00000000ed1e4b23): kobject_uevent_env kobject: 'loop1' (00000000ed1e4b23): fill_kobj_path: path = '/devices/virtual/block/loop1' audit: type=1804 audit(1572238871.987:57): pid=8284 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir978770137/syzkaller.b7Owe0/20/bus" dev="sda1" ino=16597 res=1 kobject: 'loop2' (0000000096c35d3e): kobject_uevent_env kobject: 'loop2' (0000000096c35d3e): fill_kobj_path: path = '/devices/virtual/block/loop2' kobject: 'loop0' (0000000075bee5ea): kobject_uevent_env kobject: 'loop0' (0000000075bee5ea): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'loop3' (000000009f250bac): kobject_uevent_env kobject: 'loop3' (000000009f250bac): fill_kobj_path: path = '/devices/virtual/block/loop3' kobject: 'loop1' (00000000ed1e4b23): kobject_uevent_env kobject: 'loop1' (00000000ed1e4b23): fill_kobj_path: path = '/devices/virtual/block/loop1'