INFO: task syz-executor.2:24354 blocked for more than 143 seconds. Not tainted 5.7.0-rc2-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D26672 24354 7175 0x80004006 Call Trace: context_switch kernel/sched/core.c:3372 [inline] __schedule+0x805/0xc90 kernel/sched/core.c:4088 schedule+0x188/0x220 kernel/sched/core.c:4163 rwsem_down_write_slowpath+0x7d0/0xd60 kernel/locking/rwsem.c:1235 __down_write kernel/locking/rwsem.c:1389 [inline] down_write+0x125/0x130 kernel/locking/rwsem.c:1532 unregister_netdevice_notifier+0x30/0x380 net/core/dev.c:1776 inode_lock include/linux/fs.h:797 [inline] __sock_release net/socket.c:604 [inline] sock_close+0x94/0x260 net/socket.c:1283 bcm_release+0x77/0x800 net/can/bcm.c:1474 atomic64_set include/asm-generic/atomic-instrumented.h:854 [inline] atomic_long_set include/asm-generic/atomic-long.h:40 [inline] rwsem_set_owner kernel/locking/rwsem.c:176 [inline] __down_write kernel/locking/rwsem.c:1391 [inline] down_write+0xcd/0x130 kernel/locking/rwsem.c:1532 __sock_release net/socket.c:605 [inline] sock_close+0xd8/0x260 net/socket.c:1283 sock_mmap+0x90/0x90 net/socket.c:1278 __fput+0x2ed/0x750 fs/file_table.c:280 task_work_run+0x147/0x1d0 kernel/task_work.c:123 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x5ef/0x1f80 kernel/exit.c:795 do_group_exit+0x15e/0x2c0 kernel/exit.c:893 get_signal+0x13cf/0x1d60 kernel/signal.c:2735 do_signal+0x33/0x610 arch/x86/kernel/signal.c:784 rcu_read_unlock_sched include/linux/rcupdate.h:732 [inline] __fd_install+0x251/0x490 fs/file.c:613 exit_to_usermode_loop arch/x86/entry/common.c:148 [inline] prepare_exit_to_usermode+0x280/0x600 arch/x86/entry/common.c:196 exit_to_usermode_loop arch/x86/entry/common.c:161 [inline] prepare_exit_to_usermode+0x32a/0x600 arch/x86/entry/common.c:196 syscall_return_slowpath+0xf9/0x420 arch/x86/entry/common.c:278 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Showing all locks held in the system: 3 locks held by kworker/u4:2/44: #0: ffff8880a9bb4938 ((wq_completion)netns){+.+.}-{0:0}, at: spin_unlock_irq include/linux/spinlock.h:403 [inline] #0: ffff8880a9bb4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x6df/0xfd0 kernel/workqueue.c:2241 #1: ffffc90000f07d80 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x71e/0xfd0 kernel/workqueue.c:2243 #2: ffffffff895ac230 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xac/0xb80 net/core/net_namespace.c:565 1 lock held by khungtaskd/1139: #0: ffffffff892e85d0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 net/mptcp/pm_netlink.c:858 1 lock held by in:imklog/6606: #0: ffff88809eb2f8b0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x25d/0x2f0 fs/file.c:826 2 locks held by syz-executor.2/24354: #0: ffff88802773a210 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:797 [inline] #0: ffff88802773a210 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: __sock_release net/socket.c:604 [inline] #0: ffff88802773a210 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: sock_close+0x94/0x260 net/socket.c:1283 #1: ffffffff895ac230 (pernet_ops_rwsem){++++}-{3:3}, at: unregister_netdevice_notifier+0x30/0x380 net/core/dev.c:1776 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1139 Comm: khungtaskd Not tainted 5.7.0-rc2-syzkaller #0 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+0x1e9/0x30e lib/dump_stack.c:118 nmi_cpu_backtrace+0x9f/0x180 lib/nmi_backtrace.c:101 arch_trigger_cpumask_backtrace+0x10/0x10 arch/x86/kernel/apic/hw_nmi.c:38 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xd2a/0xd40 kernel/hung_task.c:289 kthread+0x353/0x380 kernel/kthread.c:268 hungtask_pm_notify+0x50/0x50 kernel/hung_task.c:265 kthread_blkcg+0xd0/0xd0 kernel/kthread.c:1247 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4107 Comm: systemd-journal Not tainted 5.7.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:smack_cred_prepare+0x198/0x570 security/smack/smack_lsm.c:1948 Code: 48 8b 44 24 10 48 89 83 b8 00 00 00 48 83 c3 20 48 89 df 48 c7 c6 1b de f1 88 48 c7 c2 e8 7a 72 8b e8 5c df fb fd 48 8b 04 24 <48> 8d 68 10 48 89 e8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 RSP: 0018:ffffc90003347db8 EFLAGS: 00000246 RAX: ffff888092c29b00 RBX: ffff88809f49ca20 RCX: dffffc0000000000 RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffff88809f49ca80 RBP: ffffffff89436c70 R08: dffffc0000000000 R09: ffff88809f49ca90 R10: ffffed1013e93954 R11: 0000000000000000 R12: ffff88809f49ca10 R13: ffff88809be4bf00 R14: ffff88809f49cab0 R15: dffffc0000000000 FS: 00007fc4376958c0(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc434b70000 CR3: 0000000092c32000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: security_prepare_creds+0xc6/0x220 security/security.c:1610 prepare_creds+0x3dc/0x590 kernel/cred.c:285 do_faccessat+0x53/0x780 fs/open.c:360 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x7fc4369519c7 Code: 83 c4 08 48 3d 01 f0 ff ff 73 01 c3 48 8b 0d c8 d4 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 15 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 d4 2b 00 f7 d8 64 89 01 48 RSP: 002b:00007ffc4b4651d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffc4b4680f0 RCX: 00007fc4369519c7 RDX: 00007fc4373c2a00 RSI: 0000000000000000 RDI: 00005607fe9739a3 RBP: 00007ffc4b465210 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ffc4b4680f0 R15: 00007ffc4b465700