INFO: task syz-fuzzer:6421 blocked for more than 140 seconds. Not tainted 4.19.128-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-fuzzer D25688 6421 6412 0x00000004 Call Trace: context_switch kernel/sched/core.c:2826 [inline] __schedule+0x8a2/0x1fc0 kernel/sched/core.c:3515 schedule+0x8d/0x1b0 kernel/sched/core.c:3559 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x21a/0x3b0 kernel/locking/rwsem-xadd.c:309 call_rwsem_down_read_failed+0x14/0x30 arch/x86/lib/rwsem.S:94 __down_read arch/x86/include/asm/rwsem.h:83 [inline] down_read+0x45/0xb0 kernel/locking/rwsem.c:26 __do_page_fault+0xa80/0xde0 arch/x86/mm/fault.c:1348 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1205 RIP: 0033:0x420040 Code: Bad RIP value. RSP: 002b:000000c000049df0 EFLAGS: 00010283 RAX: 0000000000203004 RBX: 00007fd47a1957c8 RCX: 000000c0137c0000 RDX: 000000c0137c0720 RSI: 00007fd47a684000 RDI: 0000800000000000 RBP: 000000c000049e10 R08: 0000000000000026 R09: 0000000000000040 R10: 00007fd47a1957c8 R11: 0000000000001358 R12: 0000000000000003 R13: 0000000000e5bb20 R14: 0000000000000002 R15: 0000000000000000 Showing all locks held in the system: 3 locks held by kworker/0:1/14: #0: 00000000fa9c4ae6 ((wq_completion)"events"){+.+.}, at: process_one_work+0x78b/0x1580 kernel/workqueue.c:2126 #1: 00000000d849c4d9 ((work_completion)(&map->work)){+.+.}, at: process_one_work+0x7c1/0x1580 kernel/workqueue.c:2130 #2: 00000000568c15cf (rcu_preempt_state.barrier_mutex){+.+.}, at: _rcu_barrier+0x59/0x430 kernel/rcu/tree.c:3430 3 locks held by kworker/u4:1/23: #0: 000000005acc569e ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x78b/0x1580 kernel/workqueue.c:2126 #1: 00000000533f7257 (net_cleanup_work){+.+.}, at: process_one_work+0x7c1/0x1580 kernel/workqueue.c:2130 IPVS: ftp: loaded support on port[0] = 21 #2: 000000006b39856c (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x850 net/core/net_namespace.c:520 1 lock held by khungtaskd/1078: #0: 00000000cd65d272 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4440 1 lock held by khugepaged/1085: 1 lock held by in:imklog/6126: #0: 00000000df440cd3 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:767 2 locks held by agetty/6143: #0: 000000005745a3a2 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 00000000a2d8624d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1a50 drivers/tty/n_tty.c:2154 1 lock held by syz-fuzzer/6418: #0: 0000000064ed13b8 (&mm->mmap_sem){++++}, at: __do_page_fault+0xa80/0xde0 arch/x86/mm/fault.c:1348 3 locks held by kworker/u4:6/7765: #0: 000000008afcf6bf (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1823 [inline] #0: 000000008afcf6bf (&rq->lock){-.-.}, at: __schedule+0x1f9/0x1fc0 kernel/sched/core.c:3453 #1: 00000000cd65d272 (rcu_read_lock){....}, at: trace_sched_stat_runtime include/trace/events/sched.h:428 [inline] #1: 00000000cd65d272 (rcu_read_lock){....}, at: update_curr+0x2c3/0x870 kernel/sched/fair.c:857 #2: 000000008afcf6bf (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1823 [inline] #2: 000000008afcf6bf (&rq->lock){-.-.}, at: __schedule+0x1f9/0x1fc0 kernel/sched/core.c:3453 IPVS: ftp: loaded support on port[0] = 21 1 lock held by syz-executor.1/9630: #0: 00000000a95199e8 (tasklist_lock){.+.+}, at: do_wait+0x3a0/0x9c0 kernel/exit.c:1526 3 locks held by kworker/1:8/10966: #0: 00000000fa9c4ae6 ((wq_completion)"events"){+.+.}, at: process_one_work+0x78b/0x1580 kernel/workqueue.c:2126 #1: 000000005866c5b8 ((work_completion)(&map->work)){+.+.}, at: process_one_work+0x7c1/0x1580 kernel/workqueue.c:2130 #2: 00000000568c15cf (rcu_preempt_state.barrier_mutex){+.+.}, at: _rcu_barrier+0x59/0x430 kernel/rcu/tree.c:3430 2 locks held by kworker/1:11/11188: #0: 00000000fa9c4ae6 ((wq_completion)"events"){+.+.}, at: process_one_work+0x78b/0x1580 kernel/workqueue.c:2126 #1: 000000002e155cf2 (key_gc_work){+.+.}, at: process_one_work+0x7c1/0x1580 kernel/workqueue.c:2130 1 lock held by systemd-udevd/15361: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1078 Comm: khungtaskd Not tainted 4.19.128-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+0x1fc/0x2fe lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1eb lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x962/0xe40 kernel/hung_task.c:287 kthread+0x30b/0x410 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: 6421 Comm: syz-fuzzer Not tainted 4.19.128-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0033:0x41494c Code: 21 c2 48 8d 04 13 48 89 cb 89 f1 48 d3 ea 48 21 fa 48 89 44 24 50 48 89 5c 24 58 48 89 54 24 60 48 8b 6c 24 28 48 83 c4 30 c3 <48> 29 d8 48 8b 51 68 48 39 d0 72 44 0f b6 71 65 40 80 fe 40 48 19 RSP: 002b:000000c000049e70 EFLAGS: 00000246 RAX: 000000c003a2fd10 RBX: 000000c003a2e000 RCX: 00007fd47b2e90b8 RDX: 0000000000000000 RSI: 0000000000000003 RDI: fffffffffee6af90 RBP: 000000c000049e98 R08: 00007fd47b2b8fff R09: 000000c004bc4d80 R10: 000000c00002fe98 R11: 0000000000000018 R12: 000000c003a2fd10 R13: 000000c000000f00 R14: 000000c005b9a1e0 R15: ffffffffffffffff FS: 000000c00003e790 GS: 0000000000000000 IPVS: ftp: loaded support on port[0] = 21