INFO: task kcompactd0:1152 blocked for more than 143 seconds. Not tainted 5.7.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kcompactd0 D28600 1152 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3430 [inline] __schedule+0x8f3/0x1fc0 kernel/sched/core.c:4156 schedule+0xd0/0x2a0 kernel/sched/core.c:4231 io_schedule+0x17/0x60 kernel/sched/core.c:5874 wait_on_page_bit_common mm/filemap.c:1150 [inline] __lock_page+0x3e7/0x9c0 mm/filemap.c:1358 lock_page include/linux/pagemap.h:521 [inline] __unmap_and_move mm/migrate.c:1046 [inline] unmap_and_move mm/migrate.c:1207 [inline] migrate_pages+0x19f0/0x2810 mm/migrate.c:1455 compact_zone+0x1b25/0x3780 mm/compaction.c:2207 kcompactd_do_work+0x2d5/0xac0 mm/compaction.c:2564 kcompactd+0x226/0x860 mm/compaction.c:2657 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351 Showing all locks held in the system: 1 lock held by systemd/1: 1 lock held by kthreadd/2: 3 locks held by kworker/u4:3/42: 1 lock held by khungtaskd/1136: #0: ffffffff899bdd80 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 1 lock held by khugepaged/1155: 1 lock held by kswapd0/1667: 1 lock held by kswapd1/1668: 3 locks held by systemd-journal/3865: 1 lock held by systemd-udevd/3878: 2 locks held by systemd-timesyn/4219: 1 lock held by cron/6433: 2 locks held by in:imklog/6461: 2 locks held by agetty/6501: #0: ffff8880a62ea098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc90000f942e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x220/0x1b30 drivers/tty/n_tty.c:2156 1 lock held by syz-fuzzer/6793: 2 locks held by syz-fuzzer/6798: 2 locks held by syz-fuzzer/6808: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1136 Comm: khungtaskd Not tainted 5.7.0-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+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1e6/0x221 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa8c/0x1010 kernel/hung_task.c:289 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 2781 Comm: kworker/u4:5 Not tainted 5.7.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:task_irq_context kernel/locking/lockdep.c:3894 [inline] RIP: 0010:__lock_acquire+0x343/0x48a0 kernel/locking/lockdep.c:4318 Code: 8d bd b4 08 00 00 b8 02 00 00 00 48 89 fe 48 89 7c 24 40 85 d2 0f 45 d0 48 c1 ee 03 48 b8 00 00 00 00 00 fc ff df 0f b6 34 06 <48> 89 f8 83 e0 07 83 c0 03 40 38 f0 7c 09 40 84 f6 0f 85 28 1d 00 RSP: 0018:ffffc90008a67a68 EFLAGS: 00000807 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88809ea4ee34 RBP: ffff88809ea4eea0 R08: 1ffff11013d49dd3 R09: 0000000000000000 R10: ffffffff899bdd80 R11: 0000000000000001 R12: 0000000000000000 R13: ffff88809ea4e580 R14: 0000000000000000 R15: 000000000000002c FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000436790 CR3: 000000009c9eb000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4959 rcu_lock_acquire include/linux/rcupdate.h:241 [inline] rcu_read_lock include/linux/rcupdate.h:634 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:407 [inline] batadv_nc_worker+0x114/0x760 net/batman-adv/network-coding.c:718 process_one_work+0x965/0x16a0 kernel/workqueue.c:2268 worker_thread+0x96/0xe20 kernel/workqueue.c:2414 kthread+0x388/0x470 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351