INFO: task hung in blkdev_put

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 47350a9f ANDROID: x86_64_cuttlefish_defconfig: Enable lz4 ..
git tree: android-4.14
console output: https://syzkaller.appspot.com/x/log.txt?x=171ca13e400000
kernel config: https://syzkaller.appspot.com/x/.config?x=10d236078f3378a3
dashboard link: https://syzkaller.appspot.com/bug?extid=a7a7484b2c71fc6af5e5
compiler: gcc (GCC) 8.0.1 20180413 (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+a7a748...@syzkaller.appspotmail.com

b_state=0x00000029, b_size=4096
device loop0 blocksize: 512
__find_get_block_slow() failed. block=1, b_blocknr=0
b_state=0x00000029, b_size=4096
device loop0 blocksize: 512
INFO: task syz-executor0:18947 blocked for more than 140 seconds.
Not tainted 4.14.67+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0 D29432 18947 2025 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
blkdev_put+0x27/0x4d0 fs/block_dev.c:1806
blkdev_close+0x86/0xb0 fs/block_dev.c:1855
__fput+0x25e/0x6f0 fs/file_table.c:210
task_work_run+0x116/0x190 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:191 [inline]
exit_to_usermode_loop+0x12e/0x150 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
syscall_return_slowpath arch/x86/entry/common.c:267 [inline]
do_syscall_64+0x35d/0x4b0 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x410c41
RSP: 002b:00007fff92fa0760 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000410c41
RDX: 0000000000000000 RSI: 00000000007302d0 RDI: 0000000000000004
RBP: 0000000000000000 R08: 00000000000000a0 R09: ffffffffffffffff
R10: 0000000000930140 R11: 0000000000000293 R12: 0000000000000008
R13: 000000000003f037 R14: 000000000000010a R15: badc0ffeebadface
INFO: task syz-executor0:18965 blocked for more than 140 seconds.
Not tainted 4.14.67+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor0 D28520 18965 2025 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
__blkdev_get+0xf3/0xe50 fs/block_dev.c:1452
blkdev_get+0x97/0x8c0 fs/block_dev.c:1604
blkdev_open+0x1bd/0x240 fs/block_dev.c:1762
do_dentry_open+0x426/0xda0 fs/open.c:764
vfs_open+0x11c/0x210 fs/open.c:878
do_last fs/namei.c:3408 [inline]
path_openat+0x4eb/0x23a0 fs/namei.c:3550
do_filp_open+0x197/0x270 fs/namei.c:3584
do_sys_open+0x2ef/0x580 fs/open.c:1071
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x410dc1
RSP: 002b:00007fbbfc810a80 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000020000168 RCX: 0000000000410dc1
RDX: 00007fbbfc810afa RSI: 0000000000000002 RDI: 00007fbbfc810af0
RBP: 0000000000000001 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000001 R14: 00000000004c9eab R15: 0000000000000001
INFO: task syz-executor5:18958 blocked for more than 140 seconds.
Not tainted 4.14.67+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5 D28424 18958 2034 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
__rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:269 [inline]
rwsem_down_read_failed+0x21a/0x3d0 kernel/locking/rwsem-xadd.c:286
call_rwsem_down_read_failed+0x14/0x30 arch/x86/lib/rwsem.S:94
__down_read arch/x86/include/asm/rwsem.h:66 [inline]
down_read+0x45/0xa0 kernel/locking/rwsem.c:26
__get_super.part.2+0x1ce/0x280 fs/super.c:678
__get_super include/linux/spinlock.h:317 [inline]
get_super+0x29/0x50 fs/super.c:707
fsync_bdev+0x12/0xc0 fs/block_dev.c:481
invalidate_partition+0x2d/0x50 block/genhd.c:1506
drop_partitions block/partition-generic.c:442 [inline]
rescan_partitions+0xc8/0x7c0 block/partition-generic.c:515
__blkdev_reread_part+0x143/0x1c0 block/ioctl.c:173
blkdev_reread_part+0x20/0x30 block/ioctl.c:193
loop_reread_partitions+0x72/0x80 drivers/block/loop.c:614
loop_set_status+0xa84/0xf40 drivers/block/loop.c:1169
loop_set_status64+0x8d/0xe0 drivers/block/loop.c:1287
lo_ioctl+0x3cd/0x17d0 drivers/block/loop.c:1400
__blkdev_driver_ioctl block/ioctl.c:297 [inline]
blkdev_ioctl+0x57d/0x18c0 block/ioctl.c:594
block_ioctl+0xd9/0x120 fs/block_dev.c:1873
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x457089
RSP: 002b:00007fb695dabc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fb695dac6d4 RCX: 0000000000457089
RDX: 0000000020000240 RSI: 0000000000004c04 RDI: 0000000000000003
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004cf7e8 R14: 00000000004c5ba0 R15: 0000000000000000
INFO: task syz-executor5:18963 blocked for more than 140 seconds.
Not tainted 4.14.67+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5 D28936 18963 2034 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
__blkdev_get+0xf3/0xe50 fs/block_dev.c:1452
blkdev_get+0x97/0x8c0 fs/block_dev.c:1604
blkdev_open+0x1bd/0x240 fs/block_dev.c:1762
do_dentry_open+0x426/0xda0 fs/open.c:764
vfs_open+0x11c/0x210 fs/open.c:878
do_last fs/namei.c:3408 [inline]
path_openat+0x4eb/0x23a0 fs/namei.c:3550
do_filp_open+0x197/0x270 fs/namei.c:3584
do_sys_open+0x2ef/0x580 fs/open.c:1071
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x410dc1
RSP: 002b:00007fb695d8a7a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000410dc1
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007fb695d8a850
RBP: 0000000000930140 R08: 000000000000000f R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00000000ffffffff
R13: 00000000004d6d90 R14: 00000000004ca11f R15: 0000000000000001
INFO: task syz-executor5:18995 blocked for more than 140 seconds.
Not tainted 4.14.67+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor5 D29944 18995 2034 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
lo_ioctl+0x85/0x17d0 drivers/block/loop.c:1373
__blkdev_driver_ioctl block/ioctl.c:297 [inline]
blkdev_ioctl+0x57d/0x18c0 block/ioctl.c:594
block_ioctl+0xd9/0x120 fs/block_dev.c:1873
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x457089
RSP: 002b:00007fb695d48c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fb695d496d4 RCX: 0000000000457089
RDX: 0000000020000240 RSI: 0000000000004c04 RDI: 0000000000000003
RBP: 0000000000930280 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004cf7e8 R14: 00000000004c5ba0 R15: 0000000000000003
INFO: task blkid:18961 blocked for more than 140 seconds.
Not tainted 4.14.67+ #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid D27832 18961 5677 0x00000004
Call Trace:
schedule+0x7f/0x1b0 kernel/sched/core.c:3490
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3548
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x521/0x1480 kernel/locking/mutex.c:893
__blkdev_get+0xf3/0xe50 fs/block_dev.c:1452
blkdev_get+0x97/0x8c0 fs/block_dev.c:1604
blkdev_open+0x1bd/0x240 fs/block_dev.c:1762
do_dentry_open+0x426/0xda0 fs/open.c:764
vfs_open+0x11c/0x210 fs/open.c:878
do_last fs/namei.c:3408 [inline]
path_openat+0x4eb/0x23a0 fs/namei.c:3550
do_filp_open+0x197/0x270 fs/namei.c:3584
do_sys_open+0x2ef/0x580 fs/open.c:1071
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f21fa297120
RSP: 002b:00007ffcf8dd4f68 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f21fa297120
RDX: 00007ffcf8dd5f41 RSI: 0000000000000000 RDI: 00007ffcf8dd5f41
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000002058030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005

Showing all locks held in the system:
1 lock held by khungtaskd/23:
#0: (tasklist_lock){.+.+}, at: [<ffffffff98a01847>]
debug_show_all_locks+0x74/0x20f kernel/locking/lockdep.c:4541
1 lock held by rsyslogd/1856:
#0: (&f->f_pos_lock){+.+.}, at: [<ffffffff98dbcab2>]
__fdget_pos+0xa2/0xc0 fs/file.c:768
2 locks held by getty/1952:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff9951c500>]
tty_ldisc_ref_wait+0x20/0x80 drivers/tty/tty_ldisc.c:275
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff99517a7f>]
n_tty_read+0x1ff/0x15e0 drivers/tty/n_tty.c:2142
1 lock held by syz-executor0/18947:
#0: (&bdev->bd_mutex){+.+.}, at: [<ffffffff98e19647>]
blkdev_put+0x27/0x4d0 fs/block_dev.c:1806
1 lock held by syz-executor0/18965:
#0: (&bdev->bd_mutex){+.+.}, at: [<ffffffff98e188c3>]
__blkdev_get+0xf3/0xe50 fs/block_dev.c:1452
3 locks held by syz-executor5/18958:
#0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<ffffffff995cb8d5>]
lo_ioctl+0x85/0x17d0 drivers/block/loop.c:1373
#1: (&bdev->bd_mutex){+.+.}, at: [<ffffffff992fd838>]
blkdev_reread_part+0x18/0x30 block/ioctl.c:192
#2: (&type->s_umount_key#48){.+.+}, at: [<ffffffff98d61ece>]
__get_super.part.2+0x1ce/0x280 fs/super.c:678
1 lock held by syz-executor5/18963:
#0: (&bdev->bd_mutex){+.+.}, at: [<ffffffff98e188c3>]
__blkdev_get+0xf3/0xe50 fs/block_dev.c:1452
1 lock held by syz-executor5/18995:
#0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<ffffffff995cb8d5>]
lo_ioctl+0x85/0x17d0 drivers/block/loop.c:1373
1 lock held by blkid/18961:
#0: (&bdev->bd_mutex){+.+.}, at: [<ffffffff98e188c3>]
__blkdev_get+0xf3/0xe50 fs/block_dev.c:1452
1 lock held by init/19025:
#0: (tty_mutex){+.+.}, at: [<ffffffff9950bef8>] tty_open_by_driver
drivers/tty/tty_io.c:1922 [inline]
#0: (tty_mutex){+.+.}, at: [<ffffffff9950bef8>] tty_open+0x3a8/0x980
drivers/tty/tty_io.c:2006
1 lock held by init/19026:
#0: (tty_mutex){+.+.}, at: [<ffffffff9950bef8>] tty_open_by_driver
drivers/tty/tty_io.c:1922 [inline]
#0: (tty_mutex){+.+.}, at: [<ffffffff9950bef8>] tty_open+0x3a8/0x980
drivers/tty/tty_io.c:2006
1 lock held by init/19027:
#0: (tty_mutex){+.+.}, at: [<ffffffff9950bef8>] tty_open_by_driver
drivers/tty/tty_io.c:1922 [inline]
#0: (tty_mutex){+.+.}, at: [<ffffffff9950bef8>] tty_open+0x3a8/0x980
drivers/tty/tty_io.c:2006
1 lock held by init/19028:
#0: (tty_mutex){+.+.}, at: [<ffffffff9950bef8>] tty_open_by_driver
drivers/tty/tty_io.c:1922 [inline]
#0: (tty_mutex){+.+.}, at: [<ffffffff9950bef8>] tty_open+0x3a8/0x980
drivers/tty/tty_io.c:2006
1 lock held by init/19029:
#0: (tty_mutex){+.+.}, at: [<ffffffff9950bef8>] tty_open_by_driver
drivers/tty/tty_io.c:1922 [inline]
#0: (tty_mutex){+.+.}, at: [<ffffffff9950bef8>] tty_open+0x3a8/0x980
drivers/tty/tty_io.c:2006
1 lock held by init/19030:
#0: (tty_mutex){+.+.}, at: [<ffffffff9950bef8>] tty_open_by_driver
drivers/tty/tty_io.c:1922 [inline]
#0: (tty_mutex){+.+.}, at: [<ffffffff9950bef8>] tty_open+0x3a8/0x980
drivers/tty/tty_io.c:2006

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

NMI backtrace for cpu 1
CPU: 1 PID: 23 Comm: khungtaskd Not tainted 4.14.67+ #1
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0xb9/0x11b lib/dump_stack.c:53
nmi_cpu_backtrace.cold.0+0x18/0x8e lib/nmi_backtrace.c:103
nmi_trigger_cpumask_backtrace+0x121/0x146 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:196 [inline]
watchdog+0x574/0xa70 kernel/hung_task.c:252
kthread+0x348/0x420 kernel/kthread.c:232
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 19005 Comm: syz-executor7 Not tainted 4.14.67+ #1
task: ffff8801c198c680 task.stack: ffff8801c1a28000
RIP: 0010:inb arch/x86/include/asm/io.h:309 [inline]
RIP: 0010:io_serial_in+0x60/0x80 drivers/tty/serial/8250/8250_port.c:450
RSP: 0018:ffff8801c1a2f830 EFLAGS: 00000002
RAX: dffffc0000000000 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: ffffc900056a0000 RDI: ffffffff9cb1d998
RBP: ffffffff9cb1d960 R08: 0000000000000435 R09: ffffffff9bcc4848
R10: ffff8801c198ced8 R11: 0000000000000001 R12: 0000000000000020
R13: fffffbfff3963b72 R14: fffffbfff3963b35 R15: ffffffff9cb1db92
FS: 00007fa492d10700(0000) GS:ffff8801dba00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4a337eaa30 CR3: 00000001c77c8003 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:115 [inline]
wait_for_xmitr+0x90/0x1e0 drivers/tty/serial/8250/8250_port.c:2032
serial8250_console_putchar+0x19/0x50
drivers/tty/serial/8250/8250_port.c:3184
uart_console_write+0x4b/0xd0 drivers/tty/serial/serial_core.c:1876
serial8250_console_write+0x51b/0x800
drivers/tty/serial/8250/8250_port.c:3250
call_console_drivers kernel/printk/printk.c:1574 [inline]
console_unlock+0x5b9/0xb50 kernel/printk/printk.c:2233
vprintk_emit+0x241/0x4e0 kernel/printk/printk.c:1757
vprintk_func+0x58/0x136 kernel/printk/printk_safe.c:385
printk+0xa7/0xcf kernel/printk/printk.c:1829
binder_ioctl.cold.56+0x54/0x110 drivers/android/binder.c:4837
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x457089
RSP: 002b:00007fa492d0fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa492d106d4 RCX: 0000000000457089
RDX: 000000000040000b RSI: 00000000c0306201 RDI: 0000000000000005
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004cd640 R14: 00000000004c3f29 R15: 0000000000000000
Code: 30 0f b6 8d d1 00 00 00 48 8d 7d 38 48 b8 00 00 00 00 00 fc ff df 48
89 fa 48 c1 ea 03 d3 e3 80 3c 02 00 75 13 03 5d 38 89 da ec <0f> b6 c0 5b
5d c3 e8 d5 5c 7e ff eb c9 e8 fe 5c 7e ff eb e6 66


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

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[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: b3e9e81e Merge 4.4.172 into android-4.4
git tree: android-4.4
console output: https://syzkaller.appspot.com/x/log.txt?x=14130a0f400000
kernel config: https://syzkaller.appspot.com/x/.config?x=9d33f51998ee531f
dashboard link: https://syzkaller.appspot.com/bug?extid=f61fbf8eb33b33ab7b70
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+f61fbf...@syzkaller.appspotmail.com

INFO: task syz-executor4:8847 blocked for more than 140 seconds.
Not tainted 4.4.172+ #13

"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

syz-executor4 D ffff8800a8a177d8 28080 8847 2119 0x80000002
ffff8800a8a177d8 ffff8800a6300000 6a9952aabebf9fe4 ffff8800a6300000
0000000000000000 ffff8800a6300800 ffff8801db71f180 ffff8801db71f1a8
ffff8801db71e898 ffff8801d9275f00 ffff8800a6300000 ffffed0015142001
Call Trace:
[<ffffffff827095f9>] schedule+0x99/0x1d0 kernel/sched/core.c:3355
[<ffffffff82709db3>] schedule_preempt_disabled+0x13/0x20
kernel/sched/core.c:3388
[<ffffffff8270bf12>] __mutex_lock_common kernel/locking/mutex.c:582
[inline]
[<ffffffff8270bf12>] mutex_lock_nested+0x3c2/0xb80
kernel/locking/mutex.c:621
[<ffffffff8154f31b>] blkdev_put+0x2b/0x560 fs/block_dev.c:1558
[<ffffffff8154f8db>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1607
[<ffffffff8149c566>] __fput+0x246/0x710 fs/file_table.c:208
[<ffffffff8149cab6>] ____fput+0x16/0x20 fs/file_table.c:244
[<ffffffff8112f142>] task_work_run+0x202/0x2b0 kernel/task_work.c:115
[<ffffffff810d8b2a>] exit_task_work include/linux/task_work.h:21 [inline]
[<ffffffff810d8b2a>] do_exit+0x8ea/0x2a50 kernel/exit.c:755
[<ffffffff810dee81>] do_group_exit+0x111/0x300 kernel/exit.c:885
[<ffffffff81100887>] get_signal+0x517/0x1570 kernel/signal.c:2321
[<ffffffff8100bd4c>] do_signal+0x9c/0x1840 arch/x86/kernel/signal.c:712
[<ffffffff81003da7>] exit_to_usermode_loop+0x127/0x170
arch/x86/entry/common.c:184
[<ffffffff8100569b>] prepare_exit_to_usermode arch/x86/entry/common.c:221
[inline]
[<ffffffff8100569b>] syscall_return_slowpath+0x25b/0x2e0
arch/x86/entry/common.c:286
[<ffffffff82718761>] int_ret_from_sys_call+0x25/0xa3
1 lock held by syz-executor4/8847:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<ffffffff8154f31b>]
blkdev_put+0x2b/0x560 fs/block_dev.c:1558
Sending NMI to all CPUs:

NMI backtrace for cpu 0

CPU: 0 PID: 20 Comm: khungtaskd Not tainted 4.4.172+ #13
task: ffff8801da6f4740 task.stack: ffff8800001d0000
RIP: 0010:[<ffffffff8109b617>] [<ffffffff8109b617>] _flat_send_IPI_mask
arch/x86/kernel/apic/apic_flat_64.c:62 [inline]
RIP: 0010:[<ffffffff8109b617>] [<ffffffff8109b617>]
flat_send_IPI_mask+0xf7/0x1b0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0018:ffff8800001d7c88 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fc300
RBP: ffff8800001d7cb8 R08: 0000000000000018 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000003000000 R14: ffffffff82e5f2e0 R15: 0000000000000002
FS: 0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000000000625298 CR3: 00000001d4e82000 CR4: 00000000001606b0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000

DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
0000000000000001 ffffffff82e5f2e0 ffffffff831a67c0 fffffbfff0634bd4
000000000001b6c0 0000000000000008 ffff8800001d7cd8 ffffffff81092bee
0000000000000008 ffffffff82924260 ffff8800001d7d30 ffffffff81ab7e92
Call Trace:
[<ffffffff81092bee>] nmi_raise_cpu_backtrace+0x5e/0x80
arch/x86/kernel/apic/hw_nmi.c:33
[<ffffffff81ab7e92>] nmi_trigger_all_cpu_backtrace.cold+0xa1/0xae
lib/nmi_backtrace.c:85
[<ffffffff81092ca4>] arch_trigger_all_cpu_backtrace+0x14/0x20
arch/x86/kernel/apic/hw_nmi.c:38
[<ffffffff813b4556>] trigger_all_cpu_backtrace include/linux/nmi.h:44
[inline]
[<ffffffff813b4556>] check_hung_task kernel/hung_task.c:125 [inline]
[<ffffffff813b4556>] check_hung_uninterruptible_tasks
kernel/hung_task.c:182 [inline]
[<ffffffff813b4556>] watchdog.cold+0xd3/0xee kernel/hung_task.c:238
[<ffffffff811340b3>] kthread+0x273/0x310 kernel/kthread.c:211
[<ffffffff82718a45>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537
Code: 00 c3 5f ff 80 e6 10 75 e1 41 c1 e5 18 44 89 2c 25 10 c3 5f ff 44 89
fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 c3 5f ff <41> f7 c4 00
02 00 00 75 1e 4c 89 e7 57 9d 0f 1f 44 00 00 e8 e1

NMI backtrace for cpu 1

CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.4.172+ #13
task: ffff8801da6897c0 task.stack: ffff8801da698000
RIP: 0010:[<ffffffff8130942c>] [<ffffffff8130942c>]
__sanitizer_cov_trace_pc+0x4c/0x50 kernel/kcov.c:110
RSP: 0018:ffff8801db707f18 EFLAGS: 00000093
RAX: ffff8801da6897c0 RBX: ffff8801da698000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81b0a7dc RDI: ffffffff8292c000
RBP: ffff8801db707f50 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: ffffffff8292bfc0 R14: ffffffff8292c000 R15: ffff8801da698000
FS: 0000000000000000(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000000001f0c000 CR3: 00000001d760a000 CR4: 00000000001606b0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000

DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
ffffffff81b0a7dc ffff8801db7181e0 ffff8801da698000 0000000000000001
ffff8801da6a0000 dffffc0000000000 ffff8801da698000 ffff8801db707f60
ffffffff81b0a9dc ffff8801db707f90 ffffffff8116ece7 0000000000000000
Call Trace:
[<ffffffff81b0a9dc>] debug_smp_processor_id+0x1c/0x20
lib/smp_processor_id.c:56
[<ffffffff8116ece7>] scheduler_ipi+0x57/0x370 kernel/sched/core.c:1849
[<ffffffff810848c4>] __smp_reschedule_interrupt arch/x86/kernel/smp.c:257
[inline]
[<ffffffff810848c4>] smp_reschedule_interrupt+0x64/0x80
arch/x86/kernel/smp.c:263
[<ffffffff8271a59d>] reschedule_interrupt+0x9d/0xb0
arch/x86/entry/entry_64.S:791
<EOI> d [<ffffffff810a1dc2>] ? native_safe_halt+0x2/0x10
arch/x86/include/asm/irqflags.h:52
[<ffffffff81022d50>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:423
[<ffffffff811eb2b8>] default_idle_call+0x48/0x70 kernel/sched/idle.c:93
[<ffffffff811eba91>] cpuidle_idle_call kernel/sched/idle.c:157 [inline]
[<ffffffff811eba91>] cpu_idle_loop kernel/sched/idle.c:253 [inline]
[<ffffffff811eba91>] cpu_startup_entry+0x6d1/0x810 kernel/sched/idle.c:301
[<ffffffff8108719d>] start_secondary+0x31d/0x410
arch/x86/kernel/smpboot.c:245
Code: 90 50 12 00 00 83 fa 02 75 20 48 8b 88 58 12 00 00 8b 80 54 12 00 00
48 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 5d <c3> 0f 1f 00
55 ba 58 00 00 00 48 89 e5 41 55 49 89 fd 48 8b 3d

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 286f9710 Merge 4.9.168 into android-4.9
git tree: android-4.9
console output: https://syzkaller.appspot.com/x/log.txt?x=177d86fd200000
kernel config: https://syzkaller.appspot.com/x/.config?x=416e7ad1468db859
dashboard link: https://syzkaller.appspot.com/bug?extid=5260c4b1327b2f687786

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+5260c4...@syzkaller.appspotmail.com

ip6_tunnel: ip6tnl2 xmit: Local address not yet configured!
ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
INFO: task syz-executor.5:9100 blocked for more than 140 seconds.
Not tainted 4.9.168+ #39

"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

syz-executor.5 D27848 9100 5973 0x80000002
ffff8801d9798000 0000000000000000 ffff8801db721000 ffff8801cccd17c0
ffff8801db721018 ffff8801a10877d8 ffffffff8280028e ffffffff810021da
000000f80c82922e 00ff88021fffd050 ffff8801db7218f0 1ffff10034210eea
Call Trace:
[<0000000031dab54b>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
[<000000009ab718b5>] schedule_preempt_disabled+0x13/0x20
kernel/sched/core.c:3579
[<0000000049bfec1b>] __mutex_lock_common kernel/locking/mutex.c:582
[inline]
[<0000000049bfec1b>] mutex_lock_nested+0x38d/0x920
kernel/locking/mutex.c:621
[<00000000e7686fb1>] blkdev_put+0x2b/0x560 fs/block_dev.c:1629
[<00000000cc795b24>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1678
[<0000000008f1f100>] __fput+0x274/0x720 fs/file_table.c:208
[<00000000681a2e88>] ____fput+0x16/0x20 fs/file_table.c:244
[<00000000fc0b1999>] task_work_run+0x108/0x180 kernel/task_work.c:116
[<000000008bb35cc6>] exit_task_work include/linux/task_work.h:21 [inline]
[<000000008bb35cc6>] do_exit+0x78b/0x2aa0 kernel/exit.c:841
[<0000000049597ec4>] do_group_exit+0x111/0x300 kernel/exit.c:945
[<000000008dea6c1e>] get_signal+0x348/0x1aa0 kernel/signal.c:2380
[<00000000a20e4e25>] do_signal+0x9c/0x1920 arch/x86/kernel/signal.c:807
[<00000000a8391db1>] exit_to_usermode_loop+0x11c/0x160
arch/x86/entry/common.c:158
[<0000000068074359>] prepare_exit_to_usermode arch/x86/entry/common.c:194
[inline]
[<0000000068074359>] syscall_return_slowpath arch/x86/entry/common.c:263
[inline]
[<0000000068074359>] do_syscall_64+0x3f7/0x570 arch/x86/entry/common.c:290
[<000000004b304dc9>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Showing all locks held in the system:

2 locks held by khungtaskd/24:
#0: (rcu_read_lock){......}, at: [<000000004d2dec87>]
check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline]
#0: (rcu_read_lock){......}, at: [<000000004d2dec87>]
watchdog+0x13c/0xae0 kernel/hung_task.c:239
#1: (tasklist_lock){.+.+..}, at: [<00000000a5ff39a0>]
debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4339
1 lock held by rsyslogd/1901:
#0: (&f->f_pos_lock){+.+.+.}, at: [<000000000a530a94>]
__fdget_pos+0xa8/0xd0 fs/file.c:782
2 locks held by getty/2028:
#0: (&tty->ldisc_sem){++++++}, at: [<000000006cb505bb>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377
#1: (&ldata->atomic_read_lock){+.+...}, at: [<0000000041397277>]
n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.5/9100:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000e7686fb1>]
blkdev_put+0x2b/0x560 fs/block_dev.c:1629
2 locks held by syz-executor.0/15578:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<000000000fadfa39>]
__blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
#1: (loop_index_mutex){+.+.+.}, at: [<00000000a2ed40c6>]
lo_open+0x1d/0xb0 drivers/block/loop.c:1622
3 locks held by syz-executor.5/19401:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000056f939bd>]
__blkdev_put+0xbb/0x840 fs/block_dev.c:1587
#1: (loop_index_mutex){+.+.+.}, at: [<000000007df90de6>]
lo_release+0x1e/0x1b0 drivers/block/loop.c:1664
#2: (loop_ctl_mutex#2){+.+.+.}, at: [<00000000f95f85e2>] __lo_release
drivers/block/loop.c:1642 [inline]
#2: (loop_ctl_mutex#2){+.+.+.}, at: [<00000000f95f85e2>]
lo_release+0x84/0x1b0 drivers/block/loop.c:1665
2 locks held by syz-executor.3/19402:
#0: (loop_ctl_mutex/1){+.+.+.}, at: [<00000000a4fc604d>]
lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405
#1: (&bdev->bd_mutex){+.+.+.}, at: [<000000001ad3e146>]
blkdev_reread_part+0x1f/0x40 block/ioctl.c:189
2 locks held by blkid/19398:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<000000000fadfa39>]
__blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273
#1: (loop_index_mutex){+.+.+.}, at: [<00000000a2ed40c6>]
lo_open+0x1d/0xb0 drivers/block/loop.c:1622
1 lock held by blkid/19406:
#0: (&bdev->bd_mutex){+.+.+.}, at: [<000000000fadfa39>]
__blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273

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

NMI backtrace for cpu 1

CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.168+ #39
ffff8801d98d7cc8 ffffffff81b4f5d1 0000000000000001 0000000000000000
0000000000000001 ffffffff81097401 dffffc0000000000 ffff8801d98d7d00
ffffffff81b5a86c 0000000000000001 0000000000000000 0000000000000001
Call Trace:
[<00000000ff3d40d4>] __dump_stack lib/dump_stack.c:15 [inline]
[<00000000ff3d40d4>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
[<00000000e3188e5a>] nmi_cpu_backtrace.cold+0x47/0x87
lib/nmi_backtrace.c:99
[<000000006cbf6b40>] nmi_trigger_cpumask_backtrace+0x124/0x155
lib/nmi_backtrace.c:60
[<000000008fe03dbc>] arch_trigger_cpumask_backtrace+0x14/0x20
arch/x86/kernel/apic/hw_nmi.c:37
[<0000000020971751>] trigger_all_cpu_backtrace include/linux/nmi.h:58
[inline]
[<0000000020971751>] check_hung_task kernel/hung_task.c:125 [inline]
[<0000000020971751>] check_hung_uninterruptible_tasks
kernel/hung_task.c:182 [inline]
[<0000000020971751>] watchdog+0x661/0xae0 kernel/hung_task.c:239
[<000000005a3bdb92>] kthread+0x278/0x310 kernel/kthread.c:211
[<00000000ab95c44a>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373

Sending NMI from CPU 1 to CPUs 0:

NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff8280f302

[syzbot]

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

[syzbot]

[syzbot]