INFO: task syz-executor148:7017 blocked for more than 143 seconds. Not tainted 5.14.0-rc7-next-20210827-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor148 state:D stack:26944 pid: 7017 ppid: 6558 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:4955 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6302 schedule+0xd3/0x270 kernel/sched/core.c:6381 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6440 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729 vhost_net_stop_vq drivers/vhost/net.c:1350 [inline] vhost_net_stop+0x142/0x270 drivers/vhost/net.c:1364 vhost_net_release+0x9c/0x2d0 drivers/vhost/net.c:1396 __fput+0x288/0x9f0 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 exit_task_work include/linux/task_work.h:32 [inline] do_exit+0xbae/0x2a30 kernel/exit.c:825 do_group_exit+0x125/0x310 kernel/exit.c:922 __do_sys_exit_group kernel/exit.c:933 [inline] __se_sys_exit_group kernel/exit.c:931 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x43ef89 RSP: 002b:00007ffe904551c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00000000004b03b0 RCX: 000000000043ef89 RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 00007ffe90455240 R10: 00007ffe90455240 R11: 0000000000000246 R12: 00000000004b03b0 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001 Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8b97fbe0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446 1 lock held by in:imklog/6251: #0: ffff8880740de370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990 1 lock held by syz-executor148/7017: #0: ffff88806fbb0218 (&vq->mutex){+.+.}-{3:3}, at: vhost_net_stop_vq drivers/vhost/net.c:1350 [inline] #0: ffff88806fbb0218 (&vq->mutex){+.+.}-{3:3}, at: vhost_net_stop+0x142/0x270 drivers/vhost/net.c:1364 1 lock held by vhost-7017/7018: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.14.0-rc7-next-20210827-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+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:254 [inline] watchdog+0xcb7/0xed0 kernel/hung_task.c:339 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2960 Comm: systemd-journal Not tainted 5.14.0-rc7-next-20210827-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__put_user_nocheck_4+0x5/0x11 Code: 48 39 d9 73 54 0f 1f 00 66 89 01 31 c9 0f 1f 00 c3 0f 1f 44 00 00 48 bb fd ef ff ff ff 7f 00 00 48 39 d9 73 34 0f 1f 00 89 01 <31> c9 0f 1f 00 c3 66 0f 1f 44 00 00 48 bb f9 ef ff ff ff 7f 00 00 RSP: 0018:ffffc9000241fc80 EFLAGS: 00000246 RAX: 0000000000000001 RBX: 0000000000000001 RCX: 00007fffd0bcaf10 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff88801c98a2ac RBP: ffff88801c98a260 R08: 0000000000000000 R09: ffff88807b240007 R10: ffffffff81dbb85f R11: 0000000000000000 R12: ffff88801c98a258 R13: 0000555a85d7c780 R14: ffff88801c98a240 R15: dffffc0000000000 FS: 00007fc59a6be8c0(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055a11ef22b08 CR3: 000000001d815000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: epoll_put_uevent include/linux/eventpoll.h:81 [inline] ep_send_events fs/eventpoll.c:1689 [inline] ep_poll fs/eventpoll.c:1799 [inline] do_epoll_wait+0x7ac/0x1940 fs/eventpoll.c:2227 __do_sys_epoll_wait fs/eventpoll.c:2239 [inline] __se_sys_epoll_wait fs/eventpoll.c:2234 [inline] __x64_sys_epoll_wait+0x158/0x270 fs/eventpoll.c:2234 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fc5999872e3 Code: 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 83 3d 29 54 2b 00 00 75 13 49 89 ca b8 e8 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 0b c2 00 00 48 89 04 24 RSP: 002b:00007fffd0bcaf08 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8 RAX: ffffffffffffffda RBX: 0000555a85d7c1e0 RCX: 00007fc5999872e3 RDX: 0000000000000013 RSI: 00007fffd0bcaf10 RDI: 0000000000000008 RBP: 00007fffd0bcb100 R08: 00000000612981fb R09: 00007fffd0beb080 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fffd0bcaf10 R13: 0000000000000001 R14: ffffffffffffffff R15: 0005ca939b99a54d ---------------- Code disassembly (best guess): 0: 48 39 d9 cmp %rbx,%rcx 3: 73 54 jae 0x59 5: 0f 1f 00 nopl (%rax) 8: 66 89 01 mov %ax,(%rcx) b: 31 c9 xor %ecx,%ecx d: 0f 1f 00 nopl (%rax) 10: c3 retq 11: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 16: 48 bb fd ef ff ff ff movabs $0x7fffffffeffd,%rbx 1d: 7f 00 00 20: 48 39 d9 cmp %rbx,%rcx 23: 73 34 jae 0x59 25: 0f 1f 00 nopl (%rax) 28: 89 01 mov %eax,(%rcx) * 2a: 31 c9 xor %ecx,%ecx <-- trapping instruction 2c: 0f 1f 00 nopl (%rax) 2f: c3 retq 30: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) 36: 48 bb f9 ef ff ff ff movabs $0x7fffffffeff9,%rbx 3d: 7f 00 00