syzbot


INFO: task hung in loop_control_ioctl

Status: auto-closed as invalid on 2020/01/24 04:19
Reported-by: syzbot+ad3a2d6667692c2d66c3@syzkaller.appspotmail.com
First crash: 1015d, last: 1015d
similar bugs (5):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in loop_control_ioctl 4 1365d 1558d 12/22 fixed on 2019/01/15 20:25
android-414 INFO: task hung in loop_control_ioctl C 23 984d 1181d 0/1 public: reported C repro on 2019/04/13 00:01
android-49 INFO: task hung in loop_control_ioctl C 59 953d 1182d 0/3 public: reported C repro on 2019/04/12 00:00
linux-4.14 INFO: task hung in loop_control_ioctl (2) C inconclusive 5 416d 858d 0/1 upstream: reported C repro on 2020/02/29 17:00
android-44 INFO: task hung in loop_control_ioctl 6 1525d 1649d 0/2 auto-closed as invalid on 2019/02/22 15:22

Sample crash report:
audit: type=1400 audit(1569471421.453:93): avc:  denied  { map } for  pid=15030 comm="sh" path="/bin/dash" dev="sda1" ino=1473 scontext=system_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1
INFO: task syz-executor.3:14997 blocked for more than 140 seconds.
      Not tainted 4.14.146 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D28512 14997   6917 0x00000004
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
 loop_control_ioctl+0x153/0x2f0 drivers/block/loop.c:1996
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459a29
RSP: 002b:00007f01af16dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459a29
RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000008
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f01af16e6d4
R13: 00000000004c3177 R14: 00000000004d6a48 R15: 00000000ffffffff
INFO: task syz-executor.3:15022 blocked for more than 140 seconds.
      Not tainted 4.14.146 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D29408 15022   6917 0x00000004
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
 loop_control_ioctl+0x65/0x2f0 drivers/block/loop.c:1982
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459a29
RSP: 002b:00007f01af14cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459a29
RDX: 0000000000000000 RSI: 0000000000004c80 RDI: 0000000000000008
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f01af14d6d4
R13: 00000000004c314c R14: 00000000004d6a18 R15: 00000000ffffffff
INFO: task syz-executor.4:15007 blocked for more than 140 seconds.
      Not tainted 4.14.146 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28496 15007   6915 0x00000004
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
 blkdev_reread_part+0x1f/0x40 block/ioctl.c:192
 loop_reread_partitions+0x7c/0x90 drivers/block/loop.c:614
 loop_set_status+0xc25/0x11f0 drivers/block/loop.c:1183
 loop_set_status64+0xa6/0xf0 drivers/block/loop.c:1301
 lo_ioctl+0x5c1/0x1ce0 drivers/block/loop.c:1431
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x96b/0x1860 block/ioctl.c:594
 block_ioctl+0xde/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459897
RSP: 002b:00007f1ecaac59f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1ecaac66d4 RCX: 0000000000459897
RDX: 00007f1ecaac5ab0 RSI: 0000000000004c04 RDI: 0000000000000004
RBP: 0000000000000004 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000003 R14: 0000000000000004 R15: 00000000ffffffff
INFO: task syz-executor.0:15010 blocked for more than 140 seconds.
      Not tainted 4.14.146 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D28496 15010   6912 0x00000004
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
 blkdev_reread_part+0x1f/0x40 block/ioctl.c:192
 loop_reread_partitions+0x7c/0x90 drivers/block/loop.c:614
 loop_set_status+0xc25/0x11f0 drivers/block/loop.c:1183
 loop_set_status64+0xa6/0xf0 drivers/block/loop.c:1301
 lo_ioctl+0x5c1/0x1ce0 drivers/block/loop.c:1431
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x96b/0x1860 block/ioctl.c:594
 block_ioctl+0xde/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459897
RSP: 002b:00007fe09d3219f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fe09d3226d4 RCX: 0000000000459897
RDX: 00007fe09d321ab0 RSI: 0000000000004c04 RDI: 0000000000000004
RBP: 0000000000000004 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000003 R14: 0000000000000004 R15: 00000000ffffffff
INFO: task blkid:15009 blocked for more than 140 seconds.
      Not tainted 4.14.146 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D28064 15009   7098 0x00000004
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
 blkdev_put+0x2b/0x510 fs/block_dev.c:1814
 blkdev_close+0x8b/0xb0 fs/block_dev.c:1863
 __fput+0x275/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x114/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f5ab3edb2b0
RSP: 002b:00007ffd041bbae8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f5ab3edb2b0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000028 R09: 0000000001680000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000067e030
R13: 0000000000000000 R14: 0000000000000003 R15: 0000000000000005
INFO: task syz-executor.5:15015 blocked for more than 140 seconds.
      Not tainted 4.14.146 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D26944 15015   6914 0x00000004
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
 lo_release+0x20/0x1b0 drivers/block/loop.c:1666
 __blkdev_put+0x434/0x7f0 fs/block_dev.c:1791
 blkdev_put+0x88/0x510 fs/block_dev.c:1856
 blkdev_close+0x8b/0xb0 fs/block_dev.c:1863
 __fput+0x275/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x114/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x413711
RSP: 002b:00007f79101f19f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 00007f79101f26d4 RCX: 0000000000413711
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000000c
R10: 0000000000000064 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 0000000000000004 R15: 00000000ffffffff
INFO: task syz-executor.2:15016 blocked for more than 140 seconds.
      Not tainted 4.14.146 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D28816 15016   6916 0x00000004
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
 blkdev_reread_part+0x1f/0x40 block/ioctl.c:192
 loop_reread_partitions+0x7c/0x90 drivers/block/loop.c:614
 loop_set_status+0xc25/0x11f0 drivers/block/loop.c:1183
 loop_set_status64+0xa6/0xf0 drivers/block/loop.c:1301
 lo_ioctl+0x5c1/0x1ce0 drivers/block/loop.c:1431
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x96b/0x1860 block/ioctl.c:594
 block_ioctl+0xde/0x120 fs/block_dev.c:1881
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459897
RSP: 002b:00007faa3c1119f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007faa3c1126d4 RCX: 0000000000459897
RDX: 00007faa3c111ab0 RSI: 0000000000004c04 RDI: 0000000000000004
RBP: 0000000000000005 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000003 R14: 0000000000000004 R15: 00000000ffffffff
INFO: task blkid:15014 blocked for more than 140 seconds.
      Not tainted 4.14.146 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D29040 15014   7092 0x00000004
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
 lo_open+0x1d/0xb0 drivers/block/loop.c:1623
 __blkdev_get+0xaad/0x1120 fs/block_dev.c:1537
 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612
 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770
 do_dentry_open+0x73b/0xeb0 fs/open.c:777
 vfs_open+0x105/0x220 fs/open.c:891
 do_last fs/namei.c:3425 [inline]
 path_openat+0x8bd/0x3f70 fs/namei.c:3566
 do_filp_open+0x18e/0x250 fs/namei.c:3600
 do_sys_open+0x2c5/0x430 fs/open.c:1084
 SYSC_open fs/open.c:1102 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1097
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f5a431c0120
RSP: 002b:00007ffe2080d088 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5a431c0120
RDX: 00007ffe2080ef41 RSI: 0000000000000000 RDI: 00007ffe2080ef41
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000105b030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005
INFO: task blkid:15019 blocked for more than 140 seconds.
      Not tainted 4.14.146 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
blkid           D29040 15019   6874 0x00000004
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
 lo_open+0x1d/0xb0 drivers/block/loop.c:1623
 __blkdev_get+0xaad/0x1120 fs/block_dev.c:1537
 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612
 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770
 do_dentry_open+0x73b/0xeb0 fs/open.c:777
 vfs_open+0x105/0x220 fs/open.c:891
 do_last fs/namei.c:3425 [inline]
 path_openat+0x8bd/0x3f70 fs/namei.c:3566
 do_filp_open+0x18e/0x250 fs/namei.c:3600
 do_sys_open+0x2c5/0x430 fs/open.c:1084
 SYSC_open fs/open.c:1102 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1097
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f619f31b120
RSP: 002b:00007ffd5d96ed38 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f619f31b120
RDX: 00007ffd5d970f41 RSI: 0000000000000000 RDI: 00007ffd5d970f41
RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000151e030
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005
INFO: task syz-executor.1:15026 blocked for more than 140 seconds.
      Not tainted 4.14.146 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D28816 15026   6913 0x00000004
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
 __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
 blkdev_get+0xa8/0x8e0 fs/block_dev.c:1612
 blkdev_open+0x1d1/0x260 fs/block_dev.c:1770
 do_dentry_open+0x73b/0xeb0 fs/open.c:777
 vfs_open+0x105/0x220 fs/open.c:891
 do_last fs/namei.c:3425 [inline]
 path_openat+0x8bd/0x3f70 fs/namei.c:3566
 do_filp_open+0x18e/0x250 fs/namei.c:3600
 do_sys_open+0x2c5/0x430 fs/open.c:1084
 SYSC_open fs/open.c:1102 [inline]
 SyS_open+0x2d/0x40 fs/open.c:1097
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x413911
RSP: 002b:00007f74653989f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f74653996d4 RCX: 0000000000413911
RDX: 00007f7465398baa RSI: 0000000000000002 RDI: 00007f7465398ba0
RBP: 0000000000000005 R08: 0000000000000000 R09: 000000000000000a
R10: 0000000000000075 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000003 R14: 00007f74653996d4 R15: 00000000ffffffff

Showing all locks held in the system:
1 lock held by khungtaskd/1012:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff81486418>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4541
2 locks held by getty/6867:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861c0d63>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f806>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6868:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861c0d63>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f806>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6869:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861c0d63>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f806>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6870:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861c0d63>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f806>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6871:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861c0d63>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f806>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6872:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861c0d63>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f806>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by getty/6873:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff861c0d63>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff8310f806>] n_tty_read+0x1e6/0x17b0 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.3/14997:
 #0:  (loop_index_mutex){+.+.}, at: [<ffffffff83739bf5>] loop_control_ioctl+0x65/0x2f0 drivers/block/loop.c:1982
 #1:  (&lo->lo_ctl_mutex#2){+.+.}, at: [<ffffffff83739ce3>] loop_control_ioctl+0x153/0x2f0 drivers/block/loop.c:1996
1 lock held by syz-executor.3/15022:
 #0:  (loop_index_mutex){+.+.}, at: [<ffffffff83739bf5>] loop_control_ioctl+0x65/0x2f0 drivers/block/loop.c:1982
2 locks held by syz-executor.4/15007:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<ffffffff8373a06f>] lo_ioctl+0x8f/0x1ce0 drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff82cae1af>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:192
2 locks held by syz-executor.0/15010:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<ffffffff8373a06f>] lo_ioctl+0x8f/0x1ce0 drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff82cae1af>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:192
1 lock held by blkid/15009:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a8a3b>] blkdev_put+0x2b/0x510 fs/block_dev.c:1814
2 locks held by syz-executor.5/15015:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a71a6>] __blkdev_put+0xa6/0x7f0 fs/block_dev.c:1778
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff837383e0>] lo_release+0x20/0x1b0 drivers/block/loop.c:1666
2 locks held by syz-executor.2/15016:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<ffffffff8373a06f>] lo_ioctl+0x8f/0x1ce0 drivers/block/loop.c:1404
 #1:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff82cae1af>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:192
2 locks held by blkid/15014:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a7a35>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff8373381d>] lo_open+0x1d/0xb0 drivers/block/loop.c:1623
2 locks held by blkid/15019:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a7a35>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff8373381d>] lo_open+0x1d/0xb0 drivers/block/loop.c:1623
1 lock held by syz-executor.1/15026:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a7a35>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
2 locks held by blkid/15024:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a7a35>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff8373381d>] lo_open+0x1d/0xb0 drivers/block/loop.c:1623
2 locks held by blkid/15025:
 #0:  (&bdev->bd_mutex){+.+.}, at: [<ffffffff819a7a35>] __blkdev_get+0x145/0x1120 fs/block_dev.c:1457
 #1:  (loop_index_mutex){+.+.}, at: [<ffffffff8373381d>] lo_open+0x1d/0xb0 drivers/block/loop.c:1623

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

NMI backtrace for cpu 1
CPU: 1 PID: 1012 Comm: khungtaskd Not tainted 4.14.146 #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 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff861c184e

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2019/09/26 04:18 linux-4.14.y f6e27dbb1afa 24d405a3 .config log report