INFO: task hung in mount_bdev

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: c9fda4f2 Linux 4.14.152
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11aa1762e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=8e71058946820493
dashboard link: https://syzkaller.appspot.com/bug?extid=d8639cf39b7e223d5c04
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+d8639c...@syzkaller.appspotmail.com

protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
INFO: task syz-executor.2:22539 blocked for more than 140 seconds.
Not tainted 4.14.152 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2 D29704 22539 6880 0x10000004
Call Trace:
context_switch kernel/sched/core.c:2807 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
schedule+0x92/0x1c0 kernel/sched/core.c:3427
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
mount_bdev+0x76/0x370 fs/super.c:1101
udf_mount+0x35/0x40 fs/udf/super.c:132
mount_fs+0x97/0x2a1 fs/super.c:1237
vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
vfs_kern_mount fs/namespace.c:1036 [inline]
do_new_mount fs/namespace.c:2549 [inline]
do_mount+0x417/0x27d0 fs/namespace.c:2879
SYSC_mount fs/namespace.c:3095 [inline]
SyS_mount+0xab/0x120 fs/namespace.c:3072
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a219
RSP: 002b:00007f28b3b8dc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045a219
RDX: 0000000020000200 RSI: 0000000020000180 RDI: 0000000020000280
RBP: 000000000075c070 R08: 0000000020000240 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f28b3b8e6d4
R13: 00000000004c6d95 R14: 00000000004dc508 R15: 00000000ffffffff
INFO: task syz-executor.4:22519 blocked for more than 140 seconds.
Not tainted 4.14.152 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4 D28768 22519 7563 0x10000004
Call Trace:
context_switch kernel/sched/core.c:2807 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
schedule+0x92/0x1c0 kernel/sched/core.c:3427
__rwsem_down_write_failed_common kernel/locking/rwsem-xadd.c:588 [inline]
rwsem_down_write_failed+0x5ce/0xb50 kernel/locking/rwsem-xadd.c:617
call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:105
__down_write arch/x86/include/asm/rwsem.h:126 [inline]
down_write+0x53/0x90 kernel/locking/rwsem.c:56
grab_super+0x5e/0x140 fs/super.c:373
sget_userns+0x2b0/0xc30 fs/super.c:504
sget+0xd6/0x120 fs/super.c:572
mount_bdev+0xd5/0x370 fs/super.c:1107
udf_mount+0x35/0x40 fs/udf/super.c:132
mount_fs+0x97/0x2a1 fs/super.c:1237
vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
vfs_kern_mount fs/namespace.c:1036 [inline]
do_new_mount fs/namespace.c:2549 [inline]
do_mount+0x417/0x27d0 fs/namespace.c:2879
SYSC_mount fs/namespace.c:3095 [inline]
SyS_mount+0xab/0x120 fs/namespace.c:3072
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a219
RSP: 002b:00007f0dee09ac78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045a219
RDX: 0000000020000200 RSI: 0000000020000180 RDI: 0000000020000280
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0dee09b6d4
R13: 00000000004c6d95 R14: 00000000004dc508 R15: 00000000ffffffff
INFO: task syz-executor.4:22549 blocked for more than 140 seconds.
Not tainted 4.14.152 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4 D29664 22549 7563 0x10000004
Call Trace:
context_switch kernel/sched/core.c:2807 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
schedule+0x92/0x1c0 kernel/sched/core.c:3427
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
mount_bdev+0x76/0x370 fs/super.c:1101
udf_mount+0x35/0x40 fs/udf/super.c:132
mount_fs+0x97/0x2a1 fs/super.c:1237
vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
vfs_kern_mount fs/namespace.c:1036 [inline]
do_new_mount fs/namespace.c:2549 [inline]
do_mount+0x417/0x27d0 fs/namespace.c:2879
SYSC_mount fs/namespace.c:3095 [inline]
SyS_mount+0xab/0x120 fs/namespace.c:3072
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a219
RSP: 002b:00007f0dee058c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045a219
RDX: 0000000020000200 RSI: 0000000020000180 RDI: 0000000020000280
RBP: 000000000075c070 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0dee0596d4
R13: 00000000004c6d95 R14: 00000000004dc508 R15: 00000000ffffffff
INFO: task syz-executor.5:22528 blocked for more than 140 seconds.
Not tainted 4.14.152 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5 D28768 22528 6879 0x10000004
Call Trace:
context_switch kernel/sched/core.c:2807 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
schedule+0x92/0x1c0 kernel/sched/core.c:3427
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
mount_bdev+0x76/0x370 fs/super.c:1101
udf_mount+0x35/0x40 fs/udf/super.c:132
mount_fs+0x97/0x2a1 fs/super.c:1237
vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
vfs_kern_mount fs/namespace.c:1036 [inline]
do_new_mount fs/namespace.c:2549 [inline]
do_mount+0x417/0x27d0 fs/namespace.c:2879
SYSC_mount fs/namespace.c:3095 [inline]
SyS_mount+0xab/0x120 fs/namespace.c:3072
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a219
RSP: 002b:00007f89753d7c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045a219
RDX: 0000000020000200 RSI: 0000000020000180 RDI: 0000000020000280
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f89753d86d4
R13: 00000000004c6d95 R14: 00000000004dc508 R15: 00000000ffffffff
INFO: task syz-executor.5:22551 blocked for more than 140 seconds.
Not tainted 4.14.152 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5 D29704 22551 6879 0x10000004
Call Trace:
context_switch kernel/sched/core.c:2807 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
schedule+0x92/0x1c0 kernel/sched/core.c:3427
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3485
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
mount_bdev+0x76/0x370 fs/super.c:1101
udf_mount+0x35/0x40 fs/udf/super.c:132
mount_fs+0x97/0x2a1 fs/super.c:1237
vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
vfs_kern_mount fs/namespace.c:1036 [inline]
do_new_mount fs/namespace.c:2549 [inline]
do_mount+0x417/0x27d0 fs/namespace.c:2879
SYSC_mount fs/namespace.c:3095 [inline]
SyS_mount+0xab/0x120 fs/namespace.c:3072
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a219
RSP: 002b:00007f8975395c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045a219
RDX: 0000000020000200 RSI: 0000000020000180 RDI: 0000000020000280
RBP: 000000000075c070 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f89753966d4
R13: 00000000004c6d95 R14: 00000000004dc508 R15: 00000000ffffffff

Showing all locks held in the system:
1 lock held by khungtaskd/1016:
#0: (tasklist_lock){.+.+}, at: [<ffffffff814875a8>]
debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544
2 locks held by getty/6831:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff861c4153>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f506>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6832:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff861c4153>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f506>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6833:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff861c4153>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f506>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6834:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff861c4153>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f506>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6835:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff861c4153>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f506>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6836:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff861c4153>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f506>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6837:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff861c4153>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f506>]
n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.2/22539:
#0: (&bdev->bd_fsfreeze_mutex){+.+.}, at: [<ffffffff818e2d36>]
mount_bdev+0x76/0x370 fs/super.c:1101
2 locks held by syz-executor.4/22519:
#0: (&bdev->bd_fsfreeze_mutex){+.+.}, at: [<ffffffff818e2d36>]
mount_bdev+0x76/0x370 fs/super.c:1101
#1: (&type->s_umount_key#88){+.+.}, at: [<ffffffff818e11fe>]
grab_super+0x5e/0x140 fs/super.c:373
1 lock held by syz-executor.4/22549:
#0: (&bdev->bd_fsfreeze_mutex){+.+.}, at: [<ffffffff818e2d36>]
mount_bdev+0x76/0x370 fs/super.c:1101
1 lock held by syz-executor.5/22528:
#0: (&bdev->bd_fsfreeze_mutex){+.+.}, at: [<ffffffff818e2d36>]
mount_bdev+0x76/0x370 fs/super.c:1101
1 lock held by syz-executor.5/22551:
#0: (&bdev->bd_fsfreeze_mutex){+.+.}, at: [<ffffffff818e2d36>]
mount_bdev+0x76/0x370 fs/super.c:1101

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

NMI backtrace for cpu 0
CPU: 0 PID: 1016 Comm: khungtaskd Not tainted 4.14.152 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x138/0x197 lib/dump_stack.c:53
nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x141/0x189 lib/nmi_backtrace.c:62
arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
watchdog+0x5e7/0xb90 kernel/hung_task.c:274
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 22501 Comm: syz-executor.2 Not tainted 4.14.152 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
task: ffff888018020180 task.stack: ffff888087f48000
RIP: 0010:__lock_release kernel/locking/lockdep.c:3790 [inline]
RIP: 0010:lock_release+0x30d/0x940 kernel/locking/lockdep.c:4013
RSP: 0018:ffff888087f4f590 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: 1ffff11010fe9eb8 RCX: ffff888018020a28
RDX: 0000000000000000 RSI: ffff8880180209f8 RDI: ffff888018020a4a
RBP: ffff888087f4f628 R08: ffff888018020180 R09: 0000000000000002
R10: 0000000000000000 R11: ffff888018020180 R12: ffffffff8778f8e0
R13: ffffffff81702005 R14: ffffffff891ad7c0 R15: ffff888087f4f600
FS: 00007f28b3bd0700(0000) GS:ffff8880aef00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5a8bb09000 CR3: 0000000057e31000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rcu_lock_release include/linux/rcupdate.h:247 [inline]
rcu_read_unlock include/linux/rcupdate.h:685 [inline]
find_get_entry+0x23c/0x520 mm/filemap.c:1391
pagecache_get_page+0x4a/0x750 mm/filemap.c:1464
find_get_page_flags include/linux/pagemap.h:282 [inline]
__find_get_block_slow fs/buffer.c:214 [inline]
__find_get_block fs/buffer.c:1357 [inline]
__find_get_block+0x455/0xb10 fs/buffer.c:1351
__getblk_slow fs/buffer.c:1100 [inline]
__getblk_gfp+0x18b/0x710 fs/buffer.c:1383
__bread_gfp+0x2e/0x290 fs/buffer.c:1417
sb_bread include/linux/buffer_head.h:307 [inline]
udf_tread+0xe8/0x130 fs/udf/misc.c:44
udf_read_tagged+0x40/0x4b0 fs/udf/misc.c:210
udf_check_anchor_block+0x19b/0x580 fs/udf/super.c:1810
udf_scan_anchors+0x352/0x5a0 fs/udf/super.c:1872
udf_find_anchor fs/udf/super.c:1907 [inline]
udf_load_vrs+0x5c4/0xae0 fs/udf/super.c:1972
udf_fill_super+0x727/0x157f fs/udf/super.c:2164
mount_bdev+0x2be/0x370 fs/super.c:1134
udf_mount+0x35/0x40 fs/udf/super.c:132
mount_fs+0x97/0x2a1 fs/super.c:1237
vfs_kern_mount.part.0+0x5e/0x3d0 fs/namespace.c:1046
vfs_kern_mount fs/namespace.c:1036 [inline]
do_new_mount fs/namespace.c:2549 [inline]
do_mount+0x417/0x27d0 fs/namespace.c:2879
SYSC_mount fs/namespace.c:3095 [inline]
SyS_mount+0xab/0x120 fs/namespace.c:3072
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45a219
RSP: 002b:00007f28b3bcfc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045a219
RDX: 0000000020000200 RSI: 0000000020000180 RDI: 0000000020000280
RBP: 000000000075bf20 R08: 0000000020000240 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f28b3bd06d4
R13: 00000000004c6d95 R14: 00000000004dc508 R15: 00000000ffffffff
Code: 84 c0 74 08 3c 03 0f 8e 48 03 00 00 66 83 69 22 10 66 f7 41 22 f0 ff
0f 85 d4 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 75 90 <41> 8b 57 e0
48 c1 ee 03 0f b6 04 06 84 c0 74 08 3c 03 0f 8e 37


---
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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.