syzbot


INFO: task hung in __unmap_and_move (2)

Status: auto-closed as invalid on 2021/10/10 14:18
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 589d, last: 508d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in __unmap_and_move 1 752d 752d 0/24 auto-closed as invalid on 2021/02/08 10:09
upstream INFO: task hung in __unmap_and_move (3) 19 362d 412d 0/24 closed as invalid on 2022/02/07 18:59

Sample crash report:
INFO: task kcompactd0:1647 blocked for more than 143 seconds.
      Not tainted 5.14.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kcompactd0      state:D stack:24568 pid: 1647 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:4683 [inline]
 __schedule+0xc07/0x11f0 kernel/sched/core.c:5940
 schedule+0x14b/0x210 kernel/sched/core.c:6019
 io_schedule+0x83/0x100 kernel/sched/core.c:8008
 wait_on_page_bit_common+0x9ca/0x1030 mm/filemap.c:1301
 lock_page include/linux/pagemap.h:626 [inline]
 __unmap_and_move+0x921/0xca0 mm/migrate.c:1034
 unmap_and_move+0x339/0xd70 mm/migrate.c:1184
 migrate_pages+0x522/0x17a0 mm/migrate.c:1459
 compact_zone+0x2ce1/0x3cd0 mm/compaction.c:2399
 kcompactd_do_work mm/compaction.c:2814 [inline]
 kcompactd+0x8df/0x26d0 mm/compaction.c:2909
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Showing all locks held in the system:
1 lock held by kthreadd/2:
3 locks held by kworker/u4:3/57:
3 locks held by kworker/u4:4/134:
1 lock held by khungtaskd/1643:
 #0: ffffffff8c717740 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 arch/x86/pci/mmconfig_64.c:151
1 lock held by kswapd0/2142:
1 lock held by kswapd1/2143:
1 lock held by systemd-journal/4852:
2 locks held by systemd-udevd/4869:
1 lock held by cron/8098:
2 locks held by in:imklog/8130:
4 locks held by rs:main Q:Reg/8134:
2 locks held by syz-fuzzer/22670:
3 locks held by kworker/0:2/31742:
 #0: ffff888011064d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7aa/0x10c0 kernel/workqueue.c:2249
 #1: ffffc90017be7d20 ((work_completion)(&(&krcp->page_cache_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7e8/0x10c0 kernel/workqueue.c:2251
 #2: ffffffff8c7d7348 (pcpu_drain_mutex){+.+.}-{3:3}, at: __drain_all_pages+0x58/0x690 mm/page_alloc.c:3201
3 locks held by kworker/u4:0/5105:
2 locks held by systemd-udevd/10643:
 #0: ffff88802a9ba460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:375
 #1: ffff88802df33a60 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: inode_lock include/linux/fs.h:774 [inline]
 #1: ffff88802df33a60 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: open_last_lookups fs/namei.c:3295 [inline]
 #1: ffff88802df33a60 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: path_openat+0x7fa/0x36b0 fs/namei.c:3504
3 locks held by systemd-udevd/10646:
1 lock held by systemd-udevd/10649:
1 lock held by systemd-udevd/10696:
2 locks held by systemd-udevd/10745:
 #0: ffff88802a9ba460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:375
 #1: ffff88802df33a60 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: inode_lock include/linux/fs.h:774 [inline]
 #1: ffff88802df33a60 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: open_last_lookups fs/namei.c:3295 [inline]
 #1: ffff88802df33a60 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: path_openat+0x7fa/0x36b0 fs/namei.c:3504
1 lock held by systemd-udevd/10762:
3 locks held by kworker/u4:1/24990:
3 locks held by kworker/1:4/6594:
3 locks held by kworker/u4:7/12570:
3 locks held by kworker/u4:5/24611:
3 locks held by kworker/u4:6/24894:
1 lock held by kworker/u4:0/594:
1 lock held by kworker/u4:6/606:
1 lock held by kworker/u4:6/607:

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

NMI backtrace for cpu 1
CPU: 1 PID: 1643 Comm: khungtaskd Not tainted 5.14.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1d3/0x29f lib/dump_stack.c:105
 nmi_cpu_backtrace+0x16c/0x190 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x191/0x2f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xd06/0xd50 kernel/hung_task.c:295
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4787 Comm: bat_events Not tainted 5.14.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_nc_worker
RIP: 0010:__rcu_read_unlock+0x10f/0x610 kernel/rcu/tree_plugin.h:459
Code: 00 66 42 c7 44 2a 09 00 00 42 c6 44 2a 0b 00 65 48 8b 04 25 28 00 00 00 48 3b 84 24 a0 00 00 00 0f 85 62 04 00 00 48 8d 65 d8 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 0f 0b eb b7 65 8b 1d 63 43 96 7e
RSP: 0018:ffffc9000a507b58 EFLAGS: 00000246
RAX: 3d333ee90aeeb700 RBX: ffff8880293e83d0 RCX: ffff8880293e8000
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000a507b80 R08: dffffc0000000000 R09: fffffbfff1f5dfb1
R10: fffffbfff1f5dfb1 R11: 0000000000000000 R12: 1ffff1100527d079
R13: 1ffff920014a0f58 R14: ffff8880293e83cc R15: ffff8880293e8000
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c0003e1842 CR3: 0000000023912000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 rcu_read_unlock include/linux/rcupdate.h:719 [inline]
 batadv_nc_process_nc_paths+0x2c5/0x360 net/batman-adv/network-coding.c:695
 batadv_nc_worker+0x3de/0x5b0 net/batman-adv/network-coding.c:724
 process_one_work+0x833/0x10c0 kernel/workqueue.c:2276
 process_scheduled_works kernel/workqueue.c:2338 [inline]
 rescuer_thread+0x7f5/0x1100 kernel/workqueue.c:2529
 kthread+0x453/0x480 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Crashes (7):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2021/07/12 14:09 upstream e73f0f0ee754 a4869c92 .config log report info INFO: task hung in __unmap_and_move
ci-upstream-kasan-gce-smack-root 2021/07/04 12:25 upstream 3dbdb38e2869 55aa55c2 .config log report info INFO: task hung in __unmap_and_move
ci-upstream-kasan-gce-smack-root 2021/06/15 14:51 upstream 009c9aa5be65 58636922 .config log report info INFO: task hung in __unmap_and_move
ci-upstream-kasan-gce-smack-root 2021/06/14 20:14 upstream 009c9aa5be65 1ba81399 .config log report info INFO: task hung in __unmap_and_move
ci-upstream-kasan-gce-smack-root 2021/05/03 05:28 upstream d2b6f8a17919 77e2b668 .config log report info INFO: task hung in __unmap_and_move
ci-upstream-kasan-gce-smack-root 2021/04/23 19:03 upstream 18a3c5f7abfd 17f0b706 .config log report info INFO: task hung in __unmap_and_move
ci-upstream-kasan-gce-smack-root 2021/04/22 13:13 upstream 16fc44d6387e 33c28d03 .config log report info INFO: task hung in __unmap_and_move
* Struck through repros no longer work on HEAD.