NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 INFO: task khugepaged:1064 blocked for more than 140 seconds. Not tainted 4.14.178-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. khugepaged D26032 1064 2 0x80000000 Call Trace: schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_timeout+0x946/0xe40 kernel/time/timer.c:1723 do_wait_for_common kernel/sched/completion.c:91 [inline] __wait_for_common kernel/sched/completion.c:112 [inline] wait_for_common kernel/sched/completion.c:123 [inline] wait_for_completion+0x241/0x390 kernel/sched/completion.c:144 flush_work+0x3f5/0x780 kernel/workqueue.c:2893 drain_all_pages+0x39a/0x570 mm/page_alloc.c:2536 __alloc_pages_direct_reclaim mm/page_alloc.c:3616 [inline] __alloc_pages_slowpath+0xa16/0x26c0 mm/page_alloc.c:3989 __alloc_pages_nodemask+0x5d3/0x700 mm/page_alloc.c:4198 __alloc_pages include/linux/gfp.h:484 [inline] __alloc_pages_node include/linux/gfp.h:497 [inline] khugepaged_alloc_page+0x75/0x140 mm/khugepaged.c:754 collapse_huge_page+0xf9/0x2ad0 mm/khugepaged.c:962 khugepaged_scan_pmd mm/khugepaged.c:1220 [inline] khugepaged_scan_mm_slot mm/khugepaged.c:1762 [inline] khugepaged_do_scan mm/khugepaged.c:1843 [inline] khugepaged+0x20f9/0x2c90 mm/khugepaged.c:1888 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Showing all locks held in the system: 5 locks held by kworker/u4:1/22: #0: ("%s""netns"){+.+.}, at: [] work_static include/linux/workqueue.h:199 [inline] #0: ("%s""netns"){+.+.}, at: [] set_work_data kernel/workqueue.c:619 [inline] #0: ("%s""netns"){+.+.}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ("%s""netns"){+.+.}, at: [] process_one_work+0x727/0x1540 kernel/workqueue.c:2087 #1: (net_cleanup_work){+.+.}, at: [] process_one_work+0x761/0x1540 kernel/workqueue.c:2091 #2: (net_mutex){+.+.}, at: [] cleanup_net+0x123/0x820 net/core/net_namespace.c:450 #3: (rtnl_mutex){+.+.}, at: [] ip6_tnl_exit_net+0x61/0x530 net/ipv6/ip6_tunnel.c:2261 #4: (cpu_hotplug_lock.rw_sem){++++}, at: [] get_online_cpus include/linux/cpu.h:145 [inline] #4: (cpu_hotplug_lock.rw_sem){++++}, at: [] flush_all_backlogs net/core/dev.c:4654 [inline] #4: (cpu_hotplug_lock.rw_sem){++++}, at: [] rollback_registered_many+0x3f4/0xa70 net/core/dev.c:7192 1 lock held by khungtaskd/1057: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 1 lock held by khugepaged/1064: #0: (pcpu_drain_mutex){+.+.}, at: [] drain_all_pages+0x4a/0x570 mm/page_alloc.c:2493 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1057 Comm: khungtaskd Not tainted 4.14.178-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x13e/0x194 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x139/0x17e 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+0x5e2/0xb80 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 32257 Comm: syz-executor.2 Not tainted 4.14.178-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88809189c540 task.stack: ffff8880a46d8000 RIP: 0010:snd_pcm_plug_client_channels_buf+0x2ff/0x3f0 sound/core/oss/pcm_plugin.c:606 RSP: 0018:ffff8880a46dfbc0 EFLAGS: 00000a07 RAX: 1ffff11012e3b882 RBX: ffff8880971dc400 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff88808cd12840 RDI: ffff8880971dc414 RBP: 0000000000000008 R08: 0000000000000000 R09: ffffffff8a081b60 R10: ffff8880a46dfc98 R11: ffff88809189c540 R12: ffff88808cd12840 R13: 0000000000000003 R14: dffffc0000000000 R15: 0000000000000000 FS: 00007fe07832f700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020096000 CR3: 00000001ce90d000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: snd_pcm_oss_read2+0x18f/0x340 sound/core/oss/pcm_oss.c:1472 snd_pcm_oss_read1 sound/core/oss/pcm_oss.c:1513 [inline] snd_pcm_oss_read+0x358/0x5e0 sound/core/oss/pcm_oss.c:2753 __vfs_read+0xe4/0x610 fs/read_write.c:411 vfs_read+0x131/0x330 fs/read_write.c:447 SYSC_read fs/read_write.c:574 [inline] SyS_read+0xf2/0x210 fs/read_write.c:567 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45c829 RSP: 002b:00007fe07832ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00000000004fa980 RCX: 000000000045c829 RDX: 00000000000000ce RSI: 00000000200002c0 RDI: 000000000000000b RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000879 R14: 00000000004cb30b R15: 00007fe07832f6d4 Code: 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 74 08 3c 03 0f 8e 96 00 00 00 48 8d 7b 14 44 89 7b 10 48 89 f8 48 c1 e8 03 46 0f b6 04 30 <48> 89 f8 83 e0 07 83 c0 03 44 38 c0 7c 05 45 84 c0 75 79 8b 44