INFO: task syz-executor.2:15578 blocked for more than 140 seconds. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.2'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.4'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.1'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.0'. Not tainted 4.14.297-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D27616 15578 7977 0x00000004 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 schedule_timeout+0x80a/0xe90 kernel/time/timer.c:1724 do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common+0x272/0x430 kernel/sched/completion.c:123 flush_work+0x3fe/0x770 kernel/workqueue.c:2894 __cancel_work_timer+0x321/0x460 kernel/workqueue.c:2965 p9_conn_destroy net/9p/trans_fd.c:898 [inline] p9_fd_close+0x28d/0x420 net/9p/trans_fd.c:925 p9_client_create+0x736/0x12c0 net/9p/client.c:1093 v9fs_session_init+0x1c5/0x1540 fs/9p/v9fs.c:422 v9fs_mount+0x73/0x860 fs/9p/vfs_super.c:135 mount_fs+0x92/0x2a0 fs/super.c:1237 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2572 [inline] do_mount+0xe65/0x2a30 fs/namespace.c:2905 SYSC_mount fs/namespace.c:3121 [inline] SyS_mount+0xa8/0x120 fs/namespace.c:3098 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x5e/0xd3 Showing all locks held in the system: 1 lock held by khungtaskd/1532: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 2 locks held by kworker/0:3/8017: #0: ("events"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088 #1: ((&m->rq)){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092 3 locks held by kworker/u4:6/9286: #0: ("%s""netns"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088 #1: (net_cleanup_work){+.+.}, at: [] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092 #2: (net_mutex){+.+.}, at: [] cleanup_net+0x110/0x840 net/core/net_namespace.c:453 2 locks held by systemd-udevd/20111: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x19/0xb0 drivers/block/loop.c:1639 2 locks held by systemd-udevd/20112: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x19/0xb0 drivers/block/loop.c:1639 2 locks held by systemd-udevd/20133: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x19/0xb0 drivers/block/loop.c:1639 1 lock held by syz-executor.5/20182: #0: (loop_index_mutex){+.+.}, at: [] loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1998 1 lock held by syz-executor.5/20191: #0: (loop_index_mutex){+.+.}, at: [] loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1998 1 lock held by syz-executor.4/20190: #0: (loop_index_mutex){+.+.}, at: [] loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1998 1 lock held by syz-executor.0/20186: #0: (loop_index_mutex){+.+.}, at: [] loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1998 1 lock held by syz-executor.2/20188: #0: (loop_index_mutex){+.+.}, at: [] loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1998 1 lock held by syz-executor.1/20187: #0: (loop_index_mutex){+.+.}, at: [] loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1998 1 lock held by syz-executor.3/20189: #0: (loop_index_mutex){+.+.}, at: [] loop_control_ioctl+0x67/0x3f0 drivers/block/loop.c:1998 2 locks held by systemd-udevd/20177: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x19/0xb0 drivers/block/loop.c:1639 2 locks held by systemd-udevd/20179: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x19/0xb0 drivers/block/loop.c:1639 2 locks held by systemd-udevd/20202: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x191/0x1090 fs/block_dev.c:1455 #1: (loop_index_mutex){+.+.}, at: [] lo_open+0x19/0xb0 drivers/block/loop.c:1639 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1532 Comm: khungtaskd Not tainted 4.14.297-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x180 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5b9/0xb40 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:406 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff87249d8e