INFO: task kcompactd0:1167 blocked for more than 143 seconds. Not tainted 5.8.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kcompactd0 D28480 1167 2 0x00004000 Call Trace: context_switch kernel/sched/core.c:3778 [inline] __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527 schedule+0xd0/0x2a0 kernel/sched/core.c:4602 io_schedule+0xb5/0x120 kernel/sched/core.c:6252 wait_on_page_bit_common+0x52c/0xca0 mm/filemap.c:1190 lock_page include/linux/pagemap.h:548 [inline] __unmap_and_move mm/migrate.c:1046 [inline] unmap_and_move mm/migrate.c:1196 [inline] migrate_pages+0x1a2d/0x2e50 mm/migrate.c:1444 compact_zone+0x1cce/0x3a80 mm/compaction.c:2207 kcompactd_do_work+0x2bd/0x770 mm/compaction.c:2575 kcompactd+0x226/0x850 mm/compaction.c:2668 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Showing all locks held in the system: 2 locks held by systemd/1: 1 lock held by khungtaskd/1163: #0: ffffffff89bd6980 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5825 1 lock held by kswapd1/1684: 5 locks held by kworker/u4:6/3526: 2 locks held by systemd-journal/3891: 2 locks held by systemd-udevd/3907: 2 locks held by systemd-timesyn/4664: 2 locks held by in:imklog/6595: 2 locks held by cron/6545: 2 locks held by syz-fuzzer/6853: 2 locks held by syz-fuzzer/1194: 3 locks held by kworker/u4:3/18440: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1163 Comm: khungtaskd Not tainted 5.8.0-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+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xd7d/0x1000 kernel/hung_task.c:295 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 1 Comm: systemd Not tainted 5.8.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline] RIP: 0010:write_comp_data+0x13/0x80 kernel/kcov.c:218 Code: 48 8b 80 f8 13 00 00 c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 49 89 f2 65 8b 05 96 e6 8d 7e 65 48 8b 34 25 00 ff 01 00 00 01 ff 00 74 0f f6 c4 01 74 59 8b 86 04 14 00 00 85 c0 74 4f RSP: 0018:ffffc90000c7f0a0 EFLAGS: 00000046 RAX: 0000000080000001 RBX: 0000000000000000 RCX: ffffffff819ac6e6 RDX: 0000000000000000 RSI: ffff8880a9596040 RDI: 0000000000000007 RBP: ffffea0007e60740 R08: 0000000000000000 R09: ffffea0007e60747 R10: 0000000000000000 R11: 0000000000000001 R12: ffffc90000c7f248 R13: 0000000000000000 R14: dffffc0000000000 R15: ffffea0007e60748 FS: 00007f5118065500(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f511663d303 CR3: 00000000a75f0000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: PageTransHuge include/linux/page-flags.h:614 [inline] hpage_nr_pages include/linux/huge_mm.h:270 [inline] move_pages_to_lru.isra.0+0x3a6/0x1940 mm/vmscan.c:1871 shrink_inactive_list+0x384/0xd20 mm/vmscan.c:1969 shrink_list mm/vmscan.c:2173 [inline] shrink_lruvec+0x5e1/0x1150 mm/vmscan.c:2467 shrink_node_memcgs mm/vmscan.c:2656 [inline] shrink_node+0x4b0/0x1aa0 mm/vmscan.c:2770 shrink_zones mm/vmscan.c:2973 [inline] do_try_to_free_pages+0x38b/0x1340 mm/vmscan.c:3026 try_to_free_pages+0x29a/0x8b0 mm/vmscan.c:3265 __perform_reclaim mm/page_alloc.c:4223 [inline] __alloc_pages_direct_reclaim mm/page_alloc.c:4244 [inline] __alloc_pages_slowpath.constprop.0+0x947/0x27a0 mm/page_alloc.c:4650 __alloc_pages_nodemask+0x68f/0x930 mm/page_alloc.c:4863 alloc_pages_current+0x187/0x280 mm/mempolicy.c:2292 alloc_pages include/linux/gfp.h:545 [inline] __page_cache_alloc mm/filemap.c:956 [inline] __page_cache_alloc+0x31e/0x450 mm/filemap.c:941 pagecache_get_page+0x27d/0xe10 mm/filemap.c:1701 filemap_fault+0x1a99/0x2ad0 mm/filemap.c:2582 ext4_filemap_fault+0x87/0xb6 fs/ext4/inode.c:6060 __do_fault+0x10d/0x4d0 mm/memory.c:3464 do_read_fault mm/memory.c:3857 [inline] do_fault mm/memory.c:3985 [inline] handle_pte_fault mm/memory.c:4225 [inline] __handle_mm_fault mm/memory.c:4357 [inline] handle_mm_fault+0x37a3/0x43f0 mm/memory.c:4394 do_user_addr_fault+0x5a2/0xd00 arch/x86/mm/fault.c:1295 handle_page_fault arch/x86/mm/fault.c:1365 [inline] exc_page_fault+0xa8/0x160 arch/x86/mm/fault.c:1418 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:538 RIP: 0033:0x7f511663d303 Code: Bad RIP value. RSP: 002b:00007ffec6b55c60 EFLAGS: 00010293 RAX: 0000000000000001 RBX: 000055b3b28b9f50 RCX: 00007f511663d303 RDX: 0000000000000025 RSI: 00007ffec6b55c70 RDI: 0000000000000004 RBP: 00007ffec6b55f30 R08: 431bde82d7b634db R09: 0000000000002130 R10: 00000000ffffffff R11: 0000000000000293 R12: 00007ffec6b55c70 R13: 0000000000000001 R14: ffffffffffffffff R15: 0000000000000002