INFO: task hung in nbd_ioctl (3)

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syzbot

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Sep 28, 2020, 3:17:26 AM9/28/20
to ax...@kernel.dk, jo...@toxicpanda.com, linux...@vger.kernel.org, linux-...@vger.kernel.org, n...@other.debian.org, syzkall...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: a1bffa48 Merge tag 'scsi-fixes' of git://git.kernel.org/pu..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1106c3d3900000
kernel config: https://syzkaller.appspot.com/x/.config?x=240e2ebab67245c7
dashboard link: https://syzkaller.appspot.com/bug?extid=fe03c50d25c0188f7487
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=134bb14b900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fe03c5...@syzkaller.appspotmail.com

INFO: task syz-executor.0:12689 blocked for more than 143 seconds.
Not tainted 5.9.0-rc6-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0 state:D stack:28544 pid:12689 ppid: 6920 flags:0x00004004
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
schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1855
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x163/0x260 kernel/sched/completion.c:138
flush_workqueue+0x3ff/0x13e0 kernel/workqueue.c:2832
nbd_start_device_ioctl drivers/block/nbd.c:1330 [inline]
__nbd_ioctl drivers/block/nbd.c:1407 [inline]
nbd_ioctl+0x7ac/0xbc4 drivers/block/nbd.c:1447
__blkdev_driver_ioctl block/ioctl.c:224 [inline]
blkdev_ioctl+0x28c/0x700 block/ioctl.c:620
block_ioctl+0xf9/0x140 fs/block_dev.c:1871
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl fs/ioctl.c:739 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e179
Code: Bad RIP value.
RSP: 002b:00007f67f9e2bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000012e80 RCX: 000000000045e179
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 000000000118d020 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cff4
R13: 00007fff04dc253f R14: 00007f67f9e2c9c0 R15: 000000000118cff4

Showing all locks held in the system:
1 lock held by khungtaskd/1170:
#0: ffffffff8a067f40 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5852
2 locks held by systemd-journal/3919:
2 locks held by in:imklog/6562:
#0: ffff88809765b170 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930
#1: ffff8880ae435e18 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1292 [inline]
#1: ffff8880ae435e18 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x287/0x2280 kernel/sched/core.c:4445
2 locks held by kworker/u5:5/6940:
#0: ffff88809ee0e138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff88809ee0e138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
#0: ffff88809ee0e138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
#0: ffff88809ee0e138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
#0: ffff88809ee0e138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
#0: ffff88809ee0e138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
#1: ffffc90005e77da8 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244

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

NMI backtrace for cpu 0
CPU: 0 PID: 1170 Comm: khungtaskd Not tainted 5.9.0-rc6-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: 3919 Comm: systemd-journal Not tainted 5.9.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:rcu_lockdep_current_cpu_online kernel/rcu/tree.c:1162 [inline]
RIP: 0010:rcu_lockdep_current_cpu_online+0x83/0x120 kernel/rcu/tree.c:1152
Code: 3c 02 00 0f 85 92 00 00 00 48 03 1c ed 00 69 cb 89 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 18 48 89 fa 48 c1 ea 03 80 3c 02 00 <75> 79 48 8d 7b 20 48 8b 6b 18 48 b8 00 00 00 00 00 fc ff df 48 89
RSP: 0018:ffffc90005287ee0 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffff8880ae536c00 RCX: ffffffff817c170d
RDX: 1ffff11015ca6d83 RSI: 0000000000000002 RDI: ffff8880ae536c18
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8b59688f
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: ffffffff88264678 R14: 0000000000000000 R15: 0000000000000000
FS: 00007f0056f198c0(0000) GS:ffff8880ae500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0054483020 CR3: 0000000092420000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rcu_read_lock_held_common kernel/rcu/update.c:123 [inline]
rcu_read_lock_held_common kernel/rcu/update.c:113 [inline]
rcu_read_lock_sched_held+0x25/0xb0 kernel/rcu/update.c:134
trace_irq_disable include/trace/events/preemptirq.h:36 [inline]
trace_hardirqs_off_finish kernel/trace/trace_preemptirq.c:67 [inline]
trace_hardirqs_off_finish+0x26b/0x2d0 kernel/trace/trace_preemptirq.c:61
enter_from_user_mode kernel/entry/common.c:30 [inline]
syscall_enter_from_user_mode+0x18/0x60 kernel/entry/common.c:95
do_syscall_64+0xf/0x70 arch/x86/entry/common.c:41
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f00561e32e3
Code: 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 83 3d 29 54 2b 00 00 75 13 49 89 ca b8 e8 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 0b c2 00 00 48 89 04 24
RSP: 002b:00007ffd636fe6f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8
RAX: ffffffffffffffda RBX: 000056459af4d1e0 RCX: 00007f00561e32e3
RDX: 0000000000000013 RSI: 00007ffd636fe700 RDI: 0000000000000008
RBP: 00007ffd636fe8f0 R08: 000056459af57a60 R09: 00007ffd637f8080
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd636fe700
R13: 0000000000000001 R14: ffffffffffffffff R15: 0005b057a90e6ccf


---
This report is generated by a bot. It may contain errors.
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syzbot can test patches for this issue, for details see:
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syzbot

unread,
Oct 10, 2020, 11:56:06 AM10/10/20
to ax...@kernel.dk, jo...@toxicpanda.com, linux...@vger.kernel.org, linux-...@vger.kernel.org, mchr...@redhat.com, n...@other.debian.org, syzkall...@googlegroups.com
syzbot has bisected this issue to:

commit e9e006f5fcf2bab59149cb38a48a4817c1b538b4
Author: Mike Christie <mchr...@redhat.com>
Date: Sun Aug 4 19:10:06 2019 +0000

nbd: fix max number of supported devs

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=171556f0500000
start commit: fb0155a0 Merge tag 'nfs-for-5.9-3' of git://git.linux-nfs...
git tree: upstream
final oops: https://syzkaller.appspot.com/x/report.txt?x=149556f0500000
console output: https://syzkaller.appspot.com/x/log.txt?x=109556f0500000
kernel config: https://syzkaller.appspot.com/x/.config?x=41b736b7ce1b3ea4
dashboard link: https://syzkaller.appspot.com/bug?extid=fe03c50d25c0188f7487
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=173d9b17900000

Reported-by: syzbot+fe03c5...@syzkaller.appspotmail.com
Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

syzbot

unread,
Feb 16, 2021, 1:36:16 AM2/16/21
to ax...@kernel.dk, jo...@toxicpanda.com, linux...@vger.kernel.org, linux-...@vger.kernel.org, mchr...@redhat.com, n...@other.debian.org, syzkall...@googlegroups.com
syzbot has found a reproducer for the following issue on:

HEAD commit: f40ddce8 Linux 5.11
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10a8b204d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=4b919ebed7b4902
dashboard link: https://syzkaller.appspot.com/bug?extid=fe03c50d25c0188f7487
compiler: Debian clang version 11.0.1-2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11a7953cd00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11bc9914d00000

The issue was bisected to:

commit e9e006f5fcf2bab59149cb38a48a4817c1b538b4
Author: Mike Christie <mchr...@redhat.com>
Date: Sun Aug 4 19:10:06 2019 +0000

nbd: fix max number of supported devs

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=171556f0500000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fe03c5...@syzkaller.appspotmail.com
Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs")

INFO: task syz-executor645:8465 blocked for more than 143 seconds.
Not tainted 5.11.0-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor645 state:D stack:28256 pid: 8465 ppid: 8464 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:4327 [inline]
__schedule+0x999/0xe70 kernel/sched/core.c:5078
schedule+0x14b/0x200 kernel/sched/core.c:5157
schedule_timeout+0x43/0x250 kernel/time/timer.c:1854
do_wait_for_common+0x266/0x3a0 kernel/sched/completion.c:85
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x43/0x50 kernel/sched/completion.c:138
flush_workqueue+0x704/0x1620 kernel/workqueue.c:2838
nbd_start_device_ioctl drivers/block/nbd.c:1332 [inline]
__nbd_ioctl drivers/block/nbd.c:1393 [inline]
nbd_ioctl+0x76d/0x940 drivers/block/nbd.c:1433
blkdev_ioctl+0x2d6/0x5f0 block/ioctl.c:576
block_ioctl+0xae/0xf0 fs/block_dev.c:1658
vfs_ioctl fs/ioctl.c:48 [inline]
__do_sys_ioctl fs/ioctl.c:753 [inline]
__se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4441e9
RSP: 002b:00007ffc87363948 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004004a0 RCX: 00000000004441e9
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffc87363ae8 R09: 00007ffc87363ae8
R10: 00007ffc87363ae8 R11: 0000000000000246 R12: 0000000000403500
R13: 431bde82d7b634db R14: 00000000004b2018 R15: 00000000004004a0

Showing all locks held in the system:
1 lock held by khungtaskd/1644:
#0: ffffffff8c711680 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 arch/x86/pci/mmconfig_64.c:151
3 locks held by kworker/u5:0/2034:
#0: ffff888016152938 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: process_one_work+0x6f4/0xfc0 kernel/workqueue.c:2248
#1: ffffc900072afd78 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x733/0xfc0 kernel/workqueue.c:2250
#2: ffff888018ca7120 (sk_lock-AF_AX25){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1594 [inline]
#2: ffff888018ca7120 (sk_lock-AF_AX25){+.+.}-{0:0}, at: ax25_recvmsg+0x86/0x740 net/ax25/af_ax25.c:1626
1 lock held by in:imklog/8097:
#0: ffff8880198b14f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x24e/0x2f0 fs/file.c:947

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

NMI backtrace for cpu 1
CPU: 1 PID: 1644 Comm: khungtaskd Not tainted 5.11.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x137/0x1be lib/dump_stack.c:120
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:209 [inline]
watchdog+0xce9/0xd30 kernel/hung_task.c:294
kthread+0x39a/0x3c0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4866 Comm: systemd-journal Not tainted 5.11.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:rw_verify_area+0xef/0x370 fs/read_write.c:392
Code: 49 8d 9f 20 02 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 55 a5 f6 ff 48 83 3b 00 <74> 6f 49 8d 5f 28 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff
RSP: 0018:ffffc9000167fde0 EFLAGS: 00000246
RAX: 1ffff110280e66bc RBX: ffff8881407335e0 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000002000 RDI: ffffffffffffffff
RBP: ffffc9000167ff00 R08: ffffffff81c4ad94 R09: ffffed1004612f81
R10: ffffed1004612f81 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000002000 R15: ffff8881407333c0
FS: 00007f86aed678c0(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f86ac137000 CR3: 0000000012623000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
vfs_read+0x168/0xa80 fs/read_write.c:487
ksys_read+0x11b/0x220 fs/read_write.c:634
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f86ae2f6210
Code: 73 01 c3 48 8b 0d 98 7d 20 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d b9 c1 20 00 00 75 10 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 4e fc ff ff 48 89 04 24
RSP: 002b:00007ffc24b39f78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007ffc24b3c9f0 RCX: 00007f86ae2f6210
RDX: 0000000000002000 RSI: 00007ffc24b3a7f0 RDI: 0000000000000009
RBP: 0000000000000000 R08: 0000000000000008 R09: 0000000000000070
R10: 00007ffc24bb6118 R11: 0000000000000246 R12: 00007ffc24b3a7f0
R13: 00007ffc24b3c948 R14: 00005570d8efb958 R15: 0005bb6e4751e476

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