Re: INFO: task hung in nbd_ioctl (3)
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=10a8b204d0
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=11a7953cd0
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11bc9914d0
The issue was bisected to:
commit e9e006f5fcf2bab59149cb38a48a4817c1b538b4
Author: Mike Christie
Date: Sun Aug 4 19:10:06 2019 +
nbd: fix max number of supported devs
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=171556f050
final oops: https://syzkaller.appspot.com/x/report.txt?x=149556f050
console output: https://syzkaller.appspot.com/x/log.txt?x=109556f050
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fe03c50d25c0188f7...@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:0x4004
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:7ffc87363948 EFLAGS: 0246 ORIG_RAX: 0010
RAX: ffda RBX: 004004a0 RCX: 004441e9
RDX: RSI: ab03 RDI: 0003
RBP: R08: 7ffc87363ae8 R09: 7ffc87363ae8
R10: 7ffc87363ae8 R11: 0246 R12: 00403500
R13: 431bde82d7b634db R14: 004b2018 R15: 004004a0
Showing all locks held in the system:
1 lock held by khungtaskd/1644:
#0: 8c711680 (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: 888016152938 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at:
process_one_work+0x6f4/0xfc0 kernel/workqueue.c:2248
#1: c900072afd78 ((work_completion)(&args->work)){+.+.}-{0:0}, at:
process_one_work+0x733/0xfc0 kernel/workqueue.c:2250
#2: 888018ca7120 (sk_lock-AF_AX25){+.+.}-{0:0}, at: lock_sock
include/net/sock.h:1594 [inline]
#2: 888018ca7120 (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: 8880198b14f0 (&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:c9000167fde0 EFLAGS: 0246
RAX: 1110280e66bc RBX: 8881407335e0 RCX: dc00
RDX: RSI: 2000 RDI:
RBP: c9000167ff00 R08: 81c4ad94
Re: INFO: task hung in nbd_ioctl (3)
syzbot has bisected this issue to:
commit e9e006f5fcf2bab59149cb38a48a4817c1b538b4
Author: Mike Christie
Date: Sun Aug 4 19:10:06 2019 +
nbd: fix max number of supported devs
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=171556f050
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=149556f050
console output: https://syzkaller.appspot.com/x/log.txt?x=109556f050
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=173d9b1790
Reported-by: syzbot+fe03c50d25c0188f7...@syzkaller.appspotmail.com
Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs")
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
INFO: task hung in nbd_ioctl (3)
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=1106c3d390
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=134bb14b90
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fe03c50d25c0188f7...@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:0x4004
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:7f67f9e2bc78 EFLAGS: 0246 ORIG_RAX: 0010
RAX: ffda RBX: 00012e80 RCX: 0045e179
RDX: RSI: ab03 RDI: 0003
RBP: 0118d020 R08: R09:
R10: R11: 0246 R12: 0118cff4
R13: 7fff04dc253f R14: 7f67f9e2c9c0 R15: 0118cff4
Showing all locks held in the system:
1 lock held by khungtaskd/1170:
#0: 8a067f40 (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: 88809765b170 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100
fs/file.c:930
#1: 8880ae435e18 (&rq->lock){-.-.}-{2:2}, at: rq_lock
kernel/sched/sched.h:1292 [inline]
#1: 8880ae435e18 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x287/0x2280
kernel/sched/core.c:4445
2 locks held by kworker/u5:5/6940:
#0: 88809ee0e138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at:
arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: 88809ee0e138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: atomic64_set
include/asm-generic/atomic-instrumented.h:856 [inline]
#0: 88809ee0e138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at:
atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
#0: 88809ee0e138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at:
set_work_data kernel/workqueue.c:616 [inline]
#0: 88809ee0e138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at:
set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
#0: 88809ee0e138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at:
process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
#1: c90005e77da8 ((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 0
