syzbot


INFO: task hung in vfs_unlink (4)

Status: auto-obsoleted due to no activity on 2023/03/09 01:26
Reported-by: syzbot+453c5051023be5efcb8f@syzkaller.appspotmail.com
First crash: 526d, last: 526d
Similar bugs (13)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in vfs_unlink (3) 2 18d 30d 0/3 upstream: reported on 2024/03/19 12:40
linux-6.1 INFO: task hung in vfs_unlink (2) 1 147d 147d 0/3 auto-obsoleted due to no activity on 2024/03/02 11:45
linux-4.14 INFO: task hung in vfs_unlink (2) 1 1095d 1095d 0/1 auto-closed as invalid on 2021/08/17 05:41
linux-4.14 INFO: task hung in vfs_unlink 8 1340d 1582d 0/1 auto-closed as invalid on 2020/12/15 00:37
linux-4.19 INFO: task hung in vfs_unlink (2) 2 1349d 1411d 0/1 auto-closed as invalid on 2020/12/05 18:54
upstream INFO: task hung in vfs_unlink (3) ext4 1 444d 444d 0/26 auto-obsoleted due to no activity on 2023/04/30 04:19
linux-5.15 INFO: task hung in vfs_unlink 29 31d 388d 0/3 upstream: reported on 2023/03/26 16:46
upstream INFO: task hung in vfs_unlink ext4 32 1362d 1639d 0/26 auto-closed as invalid on 2020/11/23 01:14
linux-6.1 INFO: task hung in vfs_unlink 2 336d 347d 0/3 auto-obsoleted due to no activity on 2023/08/26 02:49
linux-4.19 INFO: task hung in vfs_unlink 6 1540d 1665d 0/1 auto-closed as invalid on 2020/05/28 17:30
linux-4.19 INFO: task hung in vfs_unlink (3) 1 988d 988d 0/1 auto-closed as invalid on 2021/12/01 23:35
upstream INFO: task hung in vfs_unlink (4) fs 6 182d 343d 0/26 auto-obsoleted due to no activity on 2024/01/16 15:08
upstream INFO: task hung in vfs_unlink (2) fs 1 621d 621d 0/26 auto-closed as invalid on 2022/10/05 08:13

Sample crash report:
bond0 (unregistering): Releasing backup interface bond_slave_0
bond0 (unregistering): Released all slaves
ieee802154 phy0 wpan0: encryption failed: -22
ieee802154 phy1 wpan1: encryption failed: -22
INFO: task syz-fuzzer:9293 blocked for more than 140 seconds.
      Not tainted 4.19.211-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-fuzzer      D26496  9293   8095 0x00000000
Call Trace:
 context_switch kernel/sched/core.c:2828 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3517
 schedule+0x8d/0x1b0 kernel/sched/core.c:3561
 __rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:589 [inline]
 rwsem_down_write_failed+0x3aa/0x760 kernel/locking/rwsem-xadd.c:618
 call_rwsem_down_write_failed+0x13/0x20 arch/x86/lib/rwsem.S:117
 __down_write arch/x86/include/asm/rwsem.h:142 [inline]
 down_write+0x4f/0x90 kernel/locking/rwsem.c:72
 inode_lock include/linux/fs.h:748 [inline]
 vfs_unlink+0xca/0x4e0 fs/namei.c:3993
 do_unlinkat+0x3b8/0x660 fs/namei.c:4065
 __do_sys_unlinkat fs/namei.c:4107 [inline]
 __se_sys_unlinkat fs/namei.c:4099 [inline]
 __x64_sys_unlinkat+0xbd/0x120 fs/namei.c:4099
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4ae09b
Code: Bad RIP value.
RSP: 002b:000000c00110d410 EFLAGS: 00000202 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 000000c000040800 RCX: 00000000004ae09b
RDX: 0000000000000000 RSI: 000000c0068ce050 RDI: 000000000000000f
RBP: 000000c00110d470 R08: 00007f5d26bf5501 R09: 0000000000000000
R10: 00007f5cff73bee8 R11: 0000000000000202 R12: 000000c0068ce050
R13: 0000000000000001 R14: 000000c000fba000 R15: 0000000000000005

Showing all locks held in the system:
1 lock held by systemd/1:
4 locks held by kworker/u4:0/7:
 #0: 000000006b43ca6e ((wq_completion)"%s""netns"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
 #1: 0000000055a77178 (net_cleanup_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
 #2: 00000000a7c5e25e (pernet_ops_rwsem){++++}, at: cleanup_net+0xa8/0x8b0 net/core/net_namespace.c:521
 #3: 00000000ef9c8609 (uevent_sock_mutex){+.+.}, at: kobject_uevent_env+0x85d/0x1480 lib/kobject_uevent.c:584
5 locks held by kworker/u4:1/23:
3 locks held by kworker/u4:3/124:
1 lock held by khungtaskd/1570:
 #0: 00000000b68fb5b5 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441
1 lock held by khugepaged/1577:
1 lock held by systemd-journal/4694:
1 lock held by in:imklog/7834:
 #0: 00000000bce007ee (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767
2 locks held by syz-fuzzer/8097:
1 lock held by syz-fuzzer/8104:
3 locks held by syz-fuzzer/9293:
 #0: 000000000d5b401c (sb_writers#3){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline]
 #0: 000000000d5b401c (sb_writers#3){.+.+}, at: mnt_want_write+0x3a/0xb0 fs/namespace.c:360
 #1: 000000009602c6a0 (&type->i_mutex_dir_key#3/1){+.+.}, at: inode_lock_nested include/linux/fs.h:783 [inline]
 #1: 000000009602c6a0 (&type->i_mutex_dir_key#3/1){+.+.}, at: do_unlinkat+0x27d/0x660 fs/namei.c:4051
 #2: 0000000092e16e35 (&sb->s_type->i_mutex_key#10){++++}, at: inode_lock include/linux/fs.h:748 [inline]
 #2: 0000000092e16e35 (&sb->s_type->i_mutex_key#10){++++}, at: vfs_unlink+0xca/0x4e0 fs/namei.c:3993
2 locks held by syz-fuzzer/14442:
2 locks held by syz-executor.3/8160:
3 locks held by kworker/u4:8/9587:
6 locks held by syz-executor.4/22199:
3 locks held by syz-executor.5/22205:
4 locks held by syz-executor.2/22216:

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

NMI backtrace for cpu 0
CPU: 0 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline]
 watchdog+0x991/0xe60 kernel/hung_task.c:287
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 17 Comm: migration/1 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
RIP: 0010:unwind_get_return_address arch/x86/kernel/unwind_orc.c:297 [inline]
RIP: 0010:unwind_get_return_address+0x6a/0x90 arch/x86/kernel/unwind_orc.c:292
Code: ea 03 80 3c 02 00 75 32 48 8b 7b 48 e8 9f a0 15 00 85 c0 74 d3 48 b8 00 00 00 00 00 fc ff df 48 89 ea 48 c1 ea 03 80 3c 02 00 <75> 18 48 8b 43 48 5b 5d c3 e8 c8 e4 6e 00 eb a8 48 89 ef e8 4e e5
RSP: 0018:ffff8880ba107668 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffff8880ba107690 RCX: 0000000000000000
RDX: 1ffff11017420edb RSI: ffff8880ba1074f0 RDI: ffffffff813936c5
RBP: ffff8880ba1076d8 R08: 0000000000000001 R09: 0000000000000001
R10: ffff8880ba1076ef R11: 0000000000074071 R12: ffff8880ba107720
R13: 0000000000000000 R14: 0000000000000005 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c009c8c000 CR3: 0000000093f01000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __save_stack_trace+0xaf/0x190 arch/x86/kernel/stacktrace.c:45
 save_stack mm/kasan/kasan.c:448 [inline]
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x126/0x1f0 mm/kasan/kasan.c:521
 __cache_free mm/slab.c:3503 [inline]
 kmem_cache_free+0x7f/0x260 mm/slab.c:3765
 kfree_skbmem+0xc1/0x140 net/core/skbuff.c:595
 __kfree_skb net/core/skbuff.c:655 [inline]
 consume_skb+0x120/0x3d0 net/core/skbuff.c:714
 vcan_tx+0x58c/0xb90 drivers/net/can/vcan.c:113
 __netdev_start_xmit include/linux/netdevice.h:4349 [inline]
 netdev_start_xmit include/linux/netdevice.h:4363 [inline]
 xmit_one net/core/dev.c:3256 [inline]
 dev_hard_start_xmit+0x1a8/0x920 net/core/dev.c:3272
 __dev_queue_xmit+0x269d/0x2e00 net/core/dev.c:3838
 can_send+0x4be/0xa00 net/can/af_can.c:297
 bcm_can_tx+0x565/0x800 net/can/bcm.c:300
 bcm_tx_timeout_tsklet+0x1f0/0x3a0 net/can/bcm.c:414
 tasklet_action_common.constprop.0+0x265/0x360 kernel/softirq.c:522
 __do_softirq+0x265/0x980 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:372 [inline]
 irq_exit+0x215/0x260 kernel/softirq.c:412
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1098
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894
 </IRQ>
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x50/0x80 kernel/locking/spinlock.c:192
Code: c0 98 82 f1 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 31 48 83 3d 01 31 d8 01 00 74 25 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 26 1b 28 f9 65 8b 05 9f 8d e8 77 85 c0 74 02 5d
RSP: 0018:ffff8880b5ac7e20 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff13e3053 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff8880b5ab8d04
RBP: ffff8880ba125748 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880ba125788
R13: ffff8880ba125748 R14: ffff8880ba1257c8 R15: ffff8880ba125788
 cpu_stopper_thread+0x138/0x370 kernel/stop_machine.c:498
 smpboot_thread_fn+0x655/0x9e0 kernel/smpboot.c:164
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/11/09 01:25 linux-4.19.y 3f8a27f9e27b 5fa28208 .config console log report info [disk image] [vmlinux] ci2-linux-4-19 INFO: task hung in vfs_unlink
* Struck through repros no longer work on HEAD.