====================================================== WARNING: possible circular locking dependency detected 4.19.195-syzkaller #0 Not tainted ------------------------------------------------------ kworker/u4:6/9560 is trying to acquire lock: 00000000842ac342 ((wq_completion)"events"){+.+.}, at: flush_workqueue+0xe8/0x13e0 kernel/workqueue.c:2658 but task is already holding lock: 00000000d6e118a0 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:520 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (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 -> #2 (&sb->s_type->i_mutex_key#13){+.+.}: 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 -> #1 ((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 -> #0 ((wq_completion)"events"){+.+.}: flush_workqueue+0x117/0x13e0 kernel/workqueue.c:2661 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 other info that might help us debug this: Chain exists of: (wq_completion)"events" --> &sb->s_type->i_mutex_key#13 --> pernet_ops_rwsem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(pernet_ops_rwsem); lock(&sb->s_type->i_mutex_key#13); lock(pernet_ops_rwsem); lock((wq_completion)"events"); *** DEADLOCK *** 3 locks held by kworker/u4:6/9560: #0: 00000000b5547fd0 ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000bd1fb6b4 (net_cleanup_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 00000000d6e118a0 (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:520 stack backtrace: CPU: 1 PID: 9560 Comm: kworker/u4:6 Not tainted 4.19.195-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net 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 flush_workqueue+0x117/0x13e0 kernel/workqueue.c:2661 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 IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): vxcan1: link becomes ready audit: type=1800 audit(1624781281.863:5): pid=10256 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="file0" dev="sda1" ino=13969 res=0 IPVS: ftp: loaded support on port[0] = 21 audit: type=1804 audit(1624781281.893:6): pid=10256 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.0" name="/root/syzkaller-testdir454157956/syzkaller.o6mb2B/14/file0" dev="sda1" ino=13969 res=1 EXT4-fs (loop5): Unrecognized mount option "K6ib4ʍSα" or missing value IPVS: ftp: loaded support on port[0] = 21 EXT4-fs (loop5): Unrecognized mount option "K6ib4ʍSα" or missing value audit: type=1804 audit(1624781281.963:7): pid=10269 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=ToMToU comm="syz-executor.0" name="/root/syzkaller-testdir454157956/syzkaller.o6mb2B/14/file0" dev="sda1" ino=13969 res=1 TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. audit: type=1326 audit(1624781281.973:8): auid=4294967295 uid=0 gid=0 ses=4294967295 subj==unconfined pid=10253 comm="syz-executor.0" exe="/root/syz-executor.0" sig=9 arch=c000003e syscall=231 compat=0 ip=0x4665d9 code=0x0 IPVS: ftp: loaded support on port[0] = 21 EXT4-fs (loop5): mounting ext3 file system using the ext4 subsystem audit: type=1804 audit(1624781282.253:9): pid=10316 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir497239997/syzkaller.Ey8raH/18/bus" dev="sda1" ino=13956 res=1 EXT4-fs (loop5): Can't read superblock on 2nd try netlink: 'syz-executor.3': attribute type 11 has an invalid length. audit: type=1800 audit(1624781282.303:10): pid=10318 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.2" name="file0" dev="sda1" ino=13963 res=0 netlink: 'syz-executor.3': attribute type 11 has an invalid length. audit: type=1800 audit(1624781282.313:11): pid=10318 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.2" name="file0" dev="sda1" ino=13963 res=0 audit: type=1804 audit(1624781282.433:12): pid=10316 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=ToMToU comm="syz-executor.1" name="/root/syzkaller-testdir497239997/syzkaller.Ey8raH/18/bus" dev="sda1" ino=13956 res=1 audit: type=1804 audit(1624781283.053:13): pid=10316 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.1" name="/root/syzkaller-testdir497239997/syzkaller.Ey8raH/18/bus" dev="sda1" ino=13956 res=1 TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. netlink: 'syz-executor.3': attribute type 11 has an invalid length. IPVS: ftp: loaded support on port[0] = 21 ieee802154 phy0 wpan0: encryption failed: -22 ieee802154 phy1 wpan1: encryption failed: -22 loop1: p2 < > p3 p4 loop1: partition table partially beyond EOD, truncated loop1: p3 start 225 is beyond EOD, truncated loop1: p4 size 3657465856 extends beyond EOD, truncated IPVS: ftp: loaded support on port[0] = 21 loop1: p2 < > p3 p4 loop1: p3 size 1912633224 extends beyond EOD, truncated loop1: p4 size 3657465856 extends beyond EOD, truncated loop1: p2 < > p3 p4 loop1: p3 size 1912633224 extends beyond EOD, truncated loop1: p4 size 3657465856 extends beyond EOD, truncated BFS-fs: bfs_fill_super(): loop0 is unclean, continuing hfsplus: invalid gid specified hfsplus: unable to parse mount options BFS-fs: bfs_fill_super(): Inode 0x00000002 corrupted audit: type=1804 audit(1624781284.543:14): pid=10601 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.4" name="/root/syzkaller-testdir230861472/syzkaller.Ndhdub/16/bus" dev="sda1" ino=13985 res=1 UDF-fs: bad mount option "fscontext=root" or missing value print_req_error: I/O error, dev loop0, sector 0 hfsplus: invalid gid specified F2FS-fs (loop4): Magic Mismatch, valid(0xf2f52010) - read(0x0) hfsplus: unable to parse mount options F2FS-fs (loop4): Can't find valid F2FS filesystem in 2th superblock F2FS-fs (loop4): Unrecognized mount option "bagkö`Ç~8 1ud" or missing value F2FS-fs (loop4): Magic Mismatch, valid(0xf2f52010) - read(0x0) BFS-fs: bfs_fill_super(): loop0 is unclean, continuing BFS-fs: bfs_fill_super(): Inode 0x00000002 corrupted F2FS-fs (loop4): Can't find valid F2FS filesystem in 2th superblock F2FS-fs (loop4): Unrecognized mount option "bagkö`Ç~8 1ud" or missing value UDF-fs: bad mount option "fscontext=root" or missing value hfsplus: invalid gid specified hfsplus: unable to parse mount options BFS-fs: bfs_fill_super(): loop0 is unclean, continuing BFS-fs: bfs_fill_super(): Inode 0x00000002 corrupted UDF-fs: bad mount option "fscontext=root" or missing value F2FS-fs (loop4): Magic Mismatch, valid(0xf2f52010) - read(0x0) F2FS-fs (loop4): Can't find valid F2FS filesystem in 2th superblock F2FS-fs (loop4): Unrecognized mount option "bagkö`Ç~8 1ud" or missing value F2FS-fs (loop4): Magic Mismatch, valid(0xf2f52010) - read(0x0) BFS-fs: bfs_fill_super(): loop0 is unclean, continuing BFS-fs: bfs_fill_super(): Inode 0x00000002 corrupted hfsplus: invalid gid specified hfsplus: unable to parse mount options BFS-fs: bfs_fill_super(): loop0 is unclean, continuing BFS-fs: bfs_fill_super(): Inode 0x00000002 corrupted hfsplus: invalid gid specified hfsplus: unable to parse mount options BFS-fs: bfs_fill_super(): loop0 is unclean, continuing BFS-fs: bfs_fill_super(): Inode 0x00000002 corrupted BFS-fs: bfs_fill_super(): loop2 is unclean, continuing BFS-fs: bfs_fill_super(): Inode 0x00000002 corrupted BFS-fs: bfs_fill_super(): loop2 is unclean, continuing BFS-fs: bfs_fill_super(): Inode 0x00000002 corrupted BFS-fs: bfs_fill_super(): loop2 is unclean, continuing BFS-fs: bfs_fill_super(): Inode 0x00000002 corrupted BFS-fs: bfs_fill_super(): loop2 is unclean, continuing BFS-fs: bfs_fill_super(): Inode 0x00000002 corrupted BFS-fs: bfs_fill_super(): loop0 is unclean, continuing BFS-fs: bfs_fill_super(): Last block not available: 63 BFS-fs: bfs_fill_super(): No BFS filesystem on loop0 (magic=00000000) BFS-fs: bfs_fill_super(): loop2 is unclean, continuing BFS-fs: bfs_fill_super(): Last block not available: 63 BFS-fs: bfs_fill_super(): No BFS filesystem on loop0 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on loop0 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on loop2 (magic=00000000) BFS-fs: bfs_fill_super(): loop0 is unclean, continuing BFS-fs: bfs_fill_super(): Last block not available: 63 BFS-fs: bfs_fill_super(): No BFS filesystem on loop2 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on loop0 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on loop2 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on loop0 (magic=00000000) BFS-fs: bfs_fill_super(): loop2 is unclean, continuing BFS-fs: bfs_fill_super(): Last block not available: 63 BFS-fs: bfs_fill_super(): No BFS filesystem on loop0 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on loop2 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on loop0 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on loop2 (magic=00000000) BFS-fs: bfs_fill_super(): No BFS filesystem on loop0 (magic=00000000)