INFO: task syz-executor.0:20406 blocked for more than 140 seconds. Not tainted 4.19.81 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29208 20406 18245 0x00000004 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x866/0x1dc0 kernel/sched/core.c:3515 schedule+0x92/0x1c0 kernel/sched/core.c:3559 __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline] rwsem_down_write_failed+0x774/0xc30 kernel/locking/rwsem-xadd.c:618 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write+0x53/0x90 kernel/locking/rwsem.c:72 register_netdevice_notifier+0x7e/0x630 net/core/dev.c:1642 bcm_init+0x1a8/0x220 net/can/bcm.c:1502 can_create+0x288/0x4a0 net/can/af_can.c:184 __sock_create+0x3d8/0x730 net/socket.c:1276 sock_create net/socket.c:1316 [inline] __sys_socket+0x103/0x220 net/socket.c:1346 __do_sys_socket net/socket.c:1355 [inline] __se_sys_socket net/socket.c:1353 [inline] __x64_sys_socket+0x73/0xb0 net/socket.c:1353 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459f49 Code: Bad RIP value. RSP: 002b:00007fb83bd5cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459f49 RDX: 0000000000000002 RSI: 0000000000000002 RDI: 000000000000001d RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb83bd5d6d4 R13: 00000000004c9052 R14: 00000000004e06a8 R15: 00000000ffffffff INFO: task syz-executor.0:20422 blocked for more than 140 seconds. Not tainted 4.19.81 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29080 20422 18245 0x00000004 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x866/0x1dc0 kernel/sched/core.c:3515 schedule+0x92/0x1c0 kernel/sched/core.c:3559 __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline] rwsem_down_write_failed+0x774/0xc30 kernel/locking/rwsem-xadd.c:618 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write+0x53/0x90 kernel/locking/rwsem.c:72 register_netdevice_notifier+0x7e/0x630 net/core/dev.c:1642 bcm_init+0x1a8/0x220 net/can/bcm.c:1502 can_create+0x288/0x4a0 net/can/af_can.c:184 __sock_create+0x3d8/0x730 net/socket.c:1276 sock_create net/socket.c:1316 [inline] __sys_socket+0x103/0x220 net/socket.c:1346 __do_sys_socket net/socket.c:1355 [inline] __se_sys_socket net/socket.c:1353 [inline] __x64_sys_socket+0x73/0xb0 net/socket.c:1353 do_syscall_64+0xfd/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459f49 Code: Bad RIP value. RSP: 002b:00007fb83bd3bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459f49 RDX: 0000000000000002 RSI: 0000000000000002 RDI: 000000000000001d RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb83bd3c6d4 R13: 00000000004c9052 R14: 00000000004e06a8 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1035: #0: 000000003208610a (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:4438 1 lock held by rsyslogd/7305: #0: 00000000e7d5a831 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:767 2 locks held by getty/7427: #0: 000000003e3e200b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 000000008acf3227 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7428: #0: 000000000eb1131e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000c510f277 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7429: #0: 00000000b3945383 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 000000004a365c19 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7430: #0: 0000000083018bbb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000d8bcf586 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7431: #0: 000000001b3031c4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000f8a2e359 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7432: #0: 000000003f99c0bb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 00000000bcf78f99 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 2 locks held by getty/7433: #0: 0000000061301ab8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:362 #1: 000000005db20a73 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154 8 locks held by syz-fuzzer/7467: #0: 00000000995f5490 (&rq->lock){-.-.}, at: idle_balance kernel/sched/fair.c:9656 [inline] #0: 00000000995f5490 (&rq->lock){-.-.}, at: pick_next_task_fair+0xfae/0x1580 kernel/sched/fair.c:6837 #1: 000000003208610a (rcu_read_lock){....}, at: __update_idle_core+0x45/0x3f0 kernel/sched/fair.c:6054 #2: 00000000129b6b12 (&obj_hash[i].lock){-.-.}, at: debug_object_activate+0x131/0x4e0 lib/debugobjects.c:472 #3: 0000000081907d72 (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x214/0x2fe0 net/core/dev.c:3777 #4: 000000004f4b46bb (&(&sch->seqlock)->rlock){+...}, at: spin_trylock include/linux/spinlock.h:339 [inline] #4: 000000004f4b46bb (&(&sch->seqlock)->rlock){+...}, at: qdisc_run_begin include/net/sch_generic.h:130 [inline] #4: 000000004f4b46bb (&(&sch->seqlock)->rlock){+...}, at: qdisc_run include/net/pkt_sched.h:119 [inline] #4: 000000004f4b46bb (&(&sch->seqlock)->rlock){+...}, at: __dev_xmit_skb net/core/dev.c:3452 [inline] #4: 000000004f4b46bb (&(&sch->seqlock)->rlock){+...}, at: __dev_queue_xmit+0x28ce/0x2fe0 net/core/dev.c:3811 #5: 00000000949e8fb2 (dev->qdisc_running_key ?: &qdisc_running_key){+..-}, at: dev_queue_xmit+0x18/0x20 net/core/dev.c:3876 #6: 0000000011646287 (_xmit_ETHER#2){+.-.}, at: spin_lock include/linux/spinlock.h:329 [inline] #6: 0000000011646287 (_xmit_ETHER#2){+.-.}, at: __netif_tx_lock include/linux/netdevice.h:3798 [inline] #6: 0000000011646287 (_xmit_ETHER#2){+.-.}, at: sch_direct_xmit+0x2de/0xfa0 net/sched/sch_generic.c:330 #7: 000000003208610a (rcu_read_lock){....}, at: dev_queue_xmit_nit+0x0/0xa10 net/core/dev.c:3994 3 locks held by kworker/u4:7/15883: #0: 0000000092bb3b5a ((wq_completion)"%s""netns"){+.+.}, at: __write_once_size include/linux/compiler.h:220 [inline] #0: 0000000092bb3b5a ((wq_completion)"%s""netns"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000092bb3b5a ((wq_completion)"%s""netns"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 0000000092bb3b5a ((wq_completion)"%s""netns"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 0000000092bb3b5a ((wq_completion)"%s""netns"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 0000000092bb3b5a ((wq_completion)"%s""netns"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 0000000092bb3b5a ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x87e/0x1750 kernel/workqueue.c:2124 #1: 00000000c687c6bc (net_cleanup_work){+.+.}, at: process_one_work+0x8b4/0x1750 kernel/workqueue.c:2128 #2: 00000000966cfe6a (pernet_ops_rwsem){++++}, at: cleanup_net+0xae/0x960 net/core/net_namespace.c:519 1 lock held by syz-executor.0/20406: #0: 00000000966cfe6a (pernet_ops_rwsem){++++}, at: register_netdevice_notifier+0x7e/0x630 net/core/dev.c:1642 1 lock held by syz-executor.0/20422: #0: 00000000966cfe6a (pernet_ops_rwsem){++++}, at: register_netdevice_notifier+0x7e/0x630 net/core/dev.c:1642 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1035 Comm: khungtaskd Not tainted 4.19.81 #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+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b0/0x1f8 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x9df/0xee0 kernel/hung_task.c:287 kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 10 Comm: rcu_preempt Not tainted 4.19.81 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:finish_swait+0x0/0x260 kernel/sched/swait.c:124 Code: 48 c1 ea 03 80 3c 02 00 75 15 4c 89 63 40 5b 41 5c 41 5d 5d c3 4c 89 e7 e8 ed 98 51 00 eb cc e8 e6 98 51 00 eb e4 0f 1f 40 00 <48> b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 57 41 56 41 55 49 89 RSP: 0018:ffff8880aa247d28 EFLAGS: 00000202 RAX: 0000000000000002 RBX: ffff8880aa247e78 RCX: 0000000000000000 RDX: 0000000000000004 RSI: ffff8880aa247e78 RDI: ffffffff887a0dd8 RBP: ffff8880aa247f00 R08: ffff8880aa238280 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffffffff8879fac0 R14: ffffffff8879fb80 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000459f1f CR3: 00000000a55db000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kthread+0x354/0x420 kernel/kthread.c:246 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415