syzbot

INFO: task kcompactd0:1180 blocked for more than 143 seconds.
      Not tainted 5.9.0-rc8-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kcompactd0      state:D stack:28760 pid: 1180 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0xec9/0x2280 kernel/sched/core.c:4527
 schedule+0xd0/0x2a0 kernel/sched/core.c:4602
 io_schedule+0xb5/0x120 kernel/sched/core.c:6296
 wait_on_page_bit_common+0x32a/0xe30 mm/filemap.c:1253
 lock_page include/linux/pagemap.h:548 [inline]
 __unmap_and_move mm/migrate.c:1047 [inline]
 unmap_and_move mm/migrate.c:1197 [inline]
 migrate_pages+0x753/0x30f0 mm/migrate.c:1458
 compact_zone+0x1b13/0x3a20 mm/compaction.c:2315
 kcompactd_do_work+0x2c7/0x790 mm/compaction.c:2725
 kcompactd+0x25d/0xd50 mm/compaction.c:2820
 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:
1 lock held by systemd/1:
3 locks held by kworker/1:1/23:
 #0: ffff8880ae535e18 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1292 [inline]
 #0: ffff8880ae535e18 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x287/0x2280 kernel/sched/core.c:4445
 #1: ffff8880ae520ec8 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x305/0x440 kernel/sched/psi.c:833
 #2: ffff8880ae525490 (krc.lock){..-.}-{2:2}, at: kfree_rcu_monitor+0x15/0x80 kernel/rcu/tree.c:3288
1 lock held by khungtaskd/1176:
 #0: ffffffff8a067f40 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5852
1 lock held by khugepaged/1183:
1 lock held by kswapd0/1696:
1 lock held by kswapd1/1697:
1 lock held by systemd-journal/3915:
2 locks held by systemd-timesyn/4101:
2 locks held by cron/6557:
3 locks held by in:imklog/6579:
5 locks held by rs:main Q:Reg/6584:
1 lock held by syz-fuzzer/6881:
2 locks held by syz-fuzzer/6893:
2 locks held by syz-fuzzer/6894:
4 locks held by kworker/u4:7/10026:
2 locks held by kworker/u4:8/10028:

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 1176 Comm: khungtaskd Not tainted 5.9.0-rc8-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+0x198/0x1fd 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3915 Comm: systemd-journal Not tainted 5.9.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:constant_test_bit arch/x86/include/asm/bitops.h:207 [inline]
RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:111 [inline]
RIP: 0010:PageActive include/linux/page-flags.h:329 [inline]
RIP: 0010:page_lru include/linux/mm_inline.h:123 [inline]
RIP: 0010:move_pages_to_lru.isra.0+0xd58/0x19d0 mm/vmscan.c:1863
Code: 4c 89 ee e8 fa db d8 ff 4d 85 ed 0f 85 4e 06 00 00 e8 6c df d8 ff be 08 00 00 00 48 89 df e8 2f 8a 19 00 48 89 d8 48 c1 e8 03 <42> 80 3c 30 00 0f 85 a9 0a 00 00 48 8b 1b 31 ff 48 c1 eb 05 83 e3
RSP: 0018:ffffc90001277150 EFLAGS: 00000802
RAX: 1ffffd4000a05e80 RBX: ffffea000502f400 RCX: ffffffff819d5fb1
RDX: fffff94000a05e81 RSI: 0000000000000008 RDI: ffffea000502f400
RBP: ffffea000502f400 R08: 0000000000000000 R09: ffffea000502f407
R10: fffff94000a05e80 R11: 0000000000000000 R12: ffffc900012772f0
R13: 0000000000000000 R14: dffffc0000000000 R15: ffffea000502f408
FS:  00007fa85ddee8c0(0000) GS:ffff8880ae500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb1a4031070 CR3: 000000009294e000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 shrink_inactive_list+0x38d/0xd40 mm/vmscan.c:1963
 shrink_list mm/vmscan.c:2168 [inline]
 shrink_lruvec+0x61b/0x11b0 mm/vmscan.c:2463
 shrink_node_memcgs mm/vmscan.c:2651 [inline]
 shrink_node+0x839/0x1d60 mm/vmscan.c:2768
 shrink_zones mm/vmscan.c:2971 [inline]
 do_try_to_free_pages+0x38b/0x1440 mm/vmscan.c:3026
 try_to_free_pages+0x29e/0x7d0 mm/vmscan.c:3265
 __perform_reclaim mm/page_alloc.c:4273 [inline]
 __alloc_pages_direct_reclaim mm/page_alloc.c:4294 [inline]
 __alloc_pages_slowpath.constprop.0+0x995/0x28c0 mm/page_alloc.c:4698
 __alloc_pages_nodemask+0x62c/0x790 mm/page_alloc.c:4914
 __alloc_pages include/linux/gfp.h:509 [inline]
 __alloc_pages_node include/linux/gfp.h:522 [inline]
 kmem_getpages mm/slab.c:1376 [inline]
 cache_grow_begin+0x71/0x4a0 mm/slab.c:2594
 fallback_alloc+0x1fb/0x2e0 mm/slab.c:3141
 __do_cache_alloc mm/slab.c:3279 [inline]
 slab_alloc mm/slab.c:3308 [inline]
 kmem_cache_alloc+0x2e3/0x3f0 mm/slab.c:3486
 getname_flags.part.0+0x50/0x4f0 fs/namei.c:138
 getname_flags include/linux/audit.h:320 [inline]
 getname+0x8e/0xd0 fs/namei.c:209
 do_sys_openat2+0xf5/0x420 fs/open.c:1162
 do_sys_open fs/open.c:1184 [inline]
 __do_sys_open fs/open.c:1192 [inline]
 __se_sys_open fs/open.c:1188 [inline]
 __x64_sys_open+0x119/0x1c0 fs/open.c:1188
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fa85d37e840
Code: 73 01 c3 48 8b 0d 68 77 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 89 bb 20 00 00 75 10 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 1e f6 ff ff 48 89 04 24
RSP: 002b:00007ffc58f4cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007ffc58f4cf80 RCX: 00007fa85d37e840
RDX: 00000000000001a0 RSI: 0000000000080042 RDI: 000055b2f31542a0
RBP: 000000000000000d R08: 000000000000ffc0 R09: 00000000ffffffff
R10: 0000000000000069 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000055b2f3147040 R14: 00007ffc58f4cf40 R15: 000055b2f3153f50