vhci_hcd: connection closed vhci_hcd: stop threads vhci_hcd: release socket vhci_hcd: disconnect device ====================================================== WARNING: possible circular locking dependency detected 4.19.195-syzkaller #0 Not tainted ------------------------------------------------------ kworker/0:1/14 is trying to acquire lock: 00000000705a05e1 (&sb->s_type->i_mutex_key#13){+.+.}, at: inode_lock include/linux/fs.h:748 [inline] 00000000705a05e1 (&sb->s_type->i_mutex_key#13){+.+.}, at: __sock_release+0x86/0x2a0 net/socket.c:578 but task is already holding lock: 000000002a153bce ((delayed_fput_work).work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 ((delayed_fput_work).work){+.+.}: worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 -> #2 ((wq_completion)"events"){+.+.}: flush_scheduled_work include/linux/workqueue.h:599 [inline] tipc_exit_net+0x38/0x60 net/tipc/core.c:100 ops_exit_list+0xa5/0x150 net/core/net_namespace.c:153 cleanup_net+0x3b4/0x8b0 net/core/net_namespace.c:553 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 -> #1 (pernet_ops_rwsem){++++}: unregister_netdevice_notifier+0x7b/0x330 net/core/dev.c:1708 bcm_release+0x94/0x700 net/can/bcm.c:1525 __sock_release+0xcd/0x2a0 net/socket.c:579 sock_close+0x15/0x20 net/socket.c:1140 __fput+0x2ce/0x890 fs/file_table.c:278 task_work_run+0x148/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&sb->s_type->i_mutex_key#13){+.+.}: down_write+0x34/0x90 kernel/locking/rwsem.c:70 inode_lock include/linux/fs.h:748 [inline] __sock_release+0x86/0x2a0 net/socket.c:578 sock_close+0x15/0x20 net/socket.c:1140 __fput+0x2ce/0x890 fs/file_table.c:278 delayed_fput+0x56/0x70 fs/file_table.c:304 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 other info that might help us debug this: Chain exists of: &sb->s_type->i_mutex_key#13 --> (wq_completion)"events" --> (delayed_fput_work).work Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock((delayed_fput_work).work); lock((wq_completion)"events"); lock((delayed_fput_work).work); lock(&sb->s_type->i_mutex_key#13); *** DEADLOCK *** 2 locks held by kworker/0:1/14: #0: 00000000641cd925 ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 000000002a153bce ((delayed_fput_work).work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 stack backtrace: CPU: 0 PID: 14 Comm: kworker/0:1 Not tainted 4.19.195-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events delayed_fput Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222 check_prev_add kernel/locking/lockdep.c:1866 [inline] check_prevs_add kernel/locking/lockdep.c:1979 [inline] validate_chain kernel/locking/lockdep.c:2420 [inline] __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 down_write+0x34/0x90 kernel/locking/rwsem.c:70 inode_lock include/linux/fs.h:748 [inline] __sock_release+0x86/0x2a0 net/socket.c:578 sock_close+0x15/0x20 net/socket.c:1140 __fput+0x2ce/0x890 fs/file_table.c:278 delayed_fput+0x56/0x70 fs/file_table.c:304 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 vhci_hcd vhci_hcd.0: pdev(1) rhport(1) sockfd(3) vhci_hcd vhci_hcd.0: devid(0) speed(3) speed_str(high-speed) vhci_hcd vhci_hcd.0: Device attached vhci_hcd: connection closed vhci_hcd: stop threads vhci_hcd: release socket vhci_hcd: disconnect device vhci_hcd vhci_hcd.0: pdev(1) rhport(0) sockfd(3) vhci_hcd vhci_hcd.0: devid(0) speed(3) speed_str(high-speed) audit: type=1800 audit(1624997596.374:106): pid=21157 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="bus" dev="sda1" ino=15091 res=0 vhci_hcd vhci_hcd.0: Device attached vhci_hcd: connection closed vhci_hcd: stop threads vhci_hcd: release socket vhci_hcd: disconnect device vhci_hcd vhci_hcd.0: pdev(1) rhport(0) sockfd(3) vhci_hcd vhci_hcd.0: devid(0) speed(3) speed_str(high-speed) vhci_hcd vhci_hcd.0: Device attached vhci_hcd: connection closed vhci_hcd: stop threads vhci_hcd: release socket vhci_hcd: disconnect device vhci_hcd vhci_hcd.0: pdev(1) rhport(0) sockfd(3) vhci_hcd vhci_hcd.0: devid(0) speed(3) speed_str(high-speed) ISO 9660 Extensions: Microsoft Joliet Level 0 vhci_hcd vhci_hcd.0: Device attached vhci_hcd: connection closed vhci_hcd: stop threads vhci_hcd: release socket vhci_hcd: disconnect device vhci_hcd: vhci_device speed not set ISO 9660 Extensions: Microsoft Joliet Level 0 ISO 9660 Extensions: Microsoft Joliet Level 0 ISO 9660 Extensions: Microsoft Joliet Level 0 ISO 9660 Extensions: Microsoft Joliet Level 0 ISO 9660 Extensions: Microsoft Joliet Level 0 ISO 9660 Extensions: Microsoft Joliet Level 0 ISO 9660 Extensions: Microsoft Joliet Level 0 ISO 9660 Extensions: Microsoft Joliet Level 0 ISO 9660 Extensions: Microsoft Joliet Level 0 PM: Marking nosave pages: [mem 0x00000000-0x00000fff] PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] PM: Basic memory bitmaps created PM: Basic memory bitmaps freed PM: Marking nosave pages: [mem 0x00000000-0x00000fff] PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] audit: type=1800 audit(1624997603.195:107): pid=21569 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed comm="syz-executor.5" name="bus" dev="sda1" ino=15147 res=0 PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] PM: Basic memory bitmaps created PM: Basic memory bitmaps freed PM: Marking nosave pages: [mem 0x00000000-0x00000fff] PM: Marking nosave pages: [mem 0x0009f000-0x000fffff] PM: Marking nosave pages: [mem 0xbfffd000-0xffffffff] PM: Basic memory bitmaps created