syzbot


INFO: task hung in ubi_detach_mtd_dev (2)

Status: upstream: reported syz repro on 2020/07/15 16:30
Reported-by: syzbot+85e4006490dfbecfd327@syzkaller.appspotmail.com
First crash: 761d, last: 761d

Fix bisection: failed (bisect log)
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in ubi_detach_mtd_dev syz error error 4 818d 904d 17/23 fixed on 2020/11/16 12:12
linux-4.14 INFO: task hung in ubi_detach_mtd_dev 6 773d 864d 0/1 auto-closed as invalid on 2020/11/01 05:07
linux-4.19 INFO: task hung in ubi_detach_mtd_dev 1 902d 902d 0/1 auto-closed as invalid on 2020/06/24 16:43

Sample crash report:
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
INFO: task syz-executor.0:23522 blocked for more than 140 seconds.
      Not tainted 4.19.132-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D29904 23522   6474 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3515
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 schedule_timeout+0x90e/0xef0 kernel/time/timer.c:1782
 do_wait_for_common kernel/sched/completion.c:83 [inline]
 __wait_for_common kernel/sched/completion.c:104 [inline]
 wait_for_common+0x29c/0x470 kernel/sched/completion.c:115
 kthread_stop+0x109/0x6b0 kernel/kthread.c:550
 ubi_detach_mtd_dev+0x21d/0x526 drivers/mtd/ubi/build.c:1093
 ctrl_cdev_ioctl+0x1be/0x2b0 drivers/mtd/ubi/cdev.c:1051
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45cba9
Code: Bad RIP value.
RSP: 002b:00007f35e1018c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e2660 RCX: 000000000045cba9
RDX: 000000000076006e RSI: 0000000040046f41 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000215 R14: 00000000004c472a R15: 00007f35e10196d4
INFO: task syz-executor.0:23527 blocked for more than 140 seconds.
      Not tainted 4.19.132-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0  D29904 23527   6474 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3515
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3617
 __mutex_lock_common kernel/locking/mutex.c:1002 [inline]
 __mutex_lock+0x647/0x1260 kernel/locking/mutex.c:1072
 ctrl_cdev_ioctl+0x213/0x2b0 drivers/mtd/ubi/cdev.c:1025
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45cba9
Code: Bad RIP value.
RSP: 002b:00007f35e0ff7c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e2660 RCX: 000000000045cba9
RDX: 000000000076006e RSI: 0000000040186f40 RDI: 0000000000000004
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000215 R14: 00000000004c472a R15: 00007f35e0ff86d4
INFO: task syz-executor.5:23533 blocked for more than 140 seconds.
      Not tainted 4.19.132-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D29904 23533   6478 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3515
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3617
 __mutex_lock_common kernel/locking/mutex.c:1002 [inline]
 __mutex_lock+0x647/0x1260 kernel/locking/mutex.c:1072
 ctrl_cdev_ioctl+0x1b5/0x2b0 drivers/mtd/ubi/cdev.c:1050
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45cba9
Code: Bad RIP value.
RSP: 002b:00007f3ba7e7ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e2660 RCX: 000000000045cba9
RDX: 000000000076006e RSI: 0000000040046f41 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000215 R14: 00000000004c472a R15: 00007f3ba7e7f6d4
INFO: task syz-executor.5:23537 blocked for more than 140 seconds.
      Not tainted 4.19.132-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D29904 23537   6478 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3515
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3617
 __mutex_lock_common kernel/locking/mutex.c:1002 [inline]
 __mutex_lock+0x647/0x1260 kernel/locking/mutex.c:1072
 ctrl_cdev_ioctl+0x213/0x2b0 drivers/mtd/ubi/cdev.c:1025
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45cba9
Code: Bad RIP value.
RSP: 002b:00007f3ba7e5dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e2660 RCX: 000000000045cba9
RDX: 000000000076006e RSI: 0000000040186f40 RDI: 0000000000000004
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000215 R14: 00000000004c472a R15: 00007f3ba7e5e6d4
INFO: task syz-executor.1:23546 blocked for more than 140 seconds.
      Not tainted 4.19.132-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D29904 23546   6469 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3515
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3617
 __mutex_lock_common kernel/locking/mutex.c:1002 [inline]
 __mutex_lock+0x647/0x1260 kernel/locking/mutex.c:1072
 ctrl_cdev_ioctl+0x1b5/0x2b0 drivers/mtd/ubi/cdev.c:1050
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45cba9
Code: Bad RIP value.
RSP: 002b:00007f75960cac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e2660 RCX: 000000000045cba9
RDX: 000000000076006e RSI: 0000000040046f41 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000215 R14: 00000000004c472a R15: 00007f75960cb6d4
INFO: task syz-executor.1:23552 blocked for more than 140 seconds.
      Not tainted 4.19.132-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D29904 23552   6469 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3515
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3617
 __mutex_lock_common kernel/locking/mutex.c:1002 [inline]
 __mutex_lock+0x647/0x1260 kernel/locking/mutex.c:1072
 ctrl_cdev_ioctl+0x213/0x2b0 drivers/mtd/ubi/cdev.c:1025
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45cba9
Code: Bad RIP value.
RSP: 002b:00007f75960a9c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e2660 RCX: 000000000045cba9
RDX: 000000000076006e RSI: 0000000040186f40 RDI: 0000000000000004
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000215 R14: 00000000004c472a R15: 00007f75960aa6d4
INFO: task syz-executor.2:23556 blocked for more than 140 seconds.
      Not tainted 4.19.132-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D29904 23556   6477 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3515
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3617
 __mutex_lock_common kernel/locking/mutex.c:1002 [inline]
 __mutex_lock+0x647/0x1260 kernel/locking/mutex.c:1072
 ctrl_cdev_ioctl+0x1b5/0x2b0 drivers/mtd/ubi/cdev.c:1050
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45cba9
Code: Bad RIP value.
RSP: 002b:00007f6be5c41c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e2660 RCX: 000000000045cba9
RDX: 000000000076006e RSI: 0000000040046f41 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000215 R14: 00000000004c472a R15: 00007f6be5c426d4
INFO: task syz-executor.2:23561 blocked for more than 140 seconds.
      Not tainted 4.19.132-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D29904 23561   6477 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3515
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3617
 __mutex_lock_common kernel/locking/mutex.c:1002 [inline]
 __mutex_lock+0x647/0x1260 kernel/locking/mutex.c:1072
 ctrl_cdev_ioctl+0x213/0x2b0 drivers/mtd/ubi/cdev.c:1025
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45cba9
Code: Bad RIP value.
RSP: 002b:00007f6be5c20c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e2660 RCX: 000000000045cba9
RDX: 000000000076006e RSI: 0000000040186f40 RDI: 0000000000000004
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000215 R14: 00000000004c472a R15: 00007f6be5c216d4
INFO: task syz-executor.4:23563 blocked for more than 140 seconds.
      Not tainted 4.19.132-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D29904 23563   6475 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3515
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3617
 __mutex_lock_common kernel/locking/mutex.c:1002 [inline]
 __mutex_lock+0x647/0x1260 kernel/locking/mutex.c:1072
 ctrl_cdev_ioctl+0x1b5/0x2b0 drivers/mtd/ubi/cdev.c:1050
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45cba9
Code: Bad RIP value.
RSP: 002b:00007f9138fb2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e2660 RCX: 000000000045cba9
RDX: 000000000076006e RSI: 0000000040046f41 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000215 R14: 00000000004c472a R15: 00007f9138fb36d4
INFO: task syz-executor.4:23568 blocked for more than 140 seconds.
      Not tainted 4.19.132-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D29904 23568   6475 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3515
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3617
 __mutex_lock_common kernel/locking/mutex.c:1002 [inline]
 __mutex_lock+0x647/0x1260 kernel/locking/mutex.c:1072
 ctrl_cdev_ioctl+0x213/0x2b0 drivers/mtd/ubi/cdev.c:1025
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45cba9
Code: Bad RIP value.
RSP: 002b:00007f9138f91c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e2660 RCX: 000000000045cba9
RDX: 000000000076006e RSI: 0000000040186f40 RDI: 0000000000000004
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000215 R14: 00000000004c472a R15: 00007f9138f926d4

Showing all locks held in the system:
1 lock held by khungtaskd/1083:
 #0: 00000000f9bd2e65 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4440
1 lock held by in:imklog/6136:
1 lock held by syz-executor.0/23522:
 #0: 000000008453d505 (ubi_devices_mutex){+.+.}, at: ctrl_cdev_ioctl+0x1b5/0x2b0 drivers/mtd/ubi/cdev.c:1050
1 lock held by syz-executor.0/23527:
 #0: 000000008453d505 (ubi_devices_mutex){+.+.}, at: ctrl_cdev_ioctl+0x213/0x2b0 drivers/mtd/ubi/cdev.c:1025
1 lock held by syz-executor.5/23533:
 #0: 000000008453d505 (ubi_devices_mutex){+.+.}, at: ctrl_cdev_ioctl+0x1b5/0x2b0 drivers/mtd/ubi/cdev.c:1050
1 lock held by syz-executor.5/23537:
 #0: 000000008453d505 (ubi_devices_mutex){+.+.}, at: ctrl_cdev_ioctl+0x213/0x2b0 drivers/mtd/ubi/cdev.c:1025
1 lock held by syz-executor.1/23546:
 #0: 000000008453d505 (ubi_devices_mutex){+.+.}, at: ctrl_cdev_ioctl+0x1b5/0x2b0 drivers/mtd/ubi/cdev.c:1050
1 lock held by syz-executor.1/23552:
 #0: 000000008453d505 (ubi_devices_mutex){+.+.}, at: ctrl_cdev_ioctl+0x213/0x2b0 drivers/mtd/ubi/cdev.c:1025
1 lock held by syz-executor.2/23556:
 #0: 000000008453d505 (ubi_devices_mutex){+.+.}, at: ctrl_cdev_ioctl+0x1b5/0x2b0 drivers/mtd/ubi/cdev.c:1050
1 lock held by syz-executor.2/23561:
 #0: 000000008453d505 (ubi_devices_mutex){+.+.}, at: ctrl_cdev_ioctl+0x213/0x2b0 drivers/mtd/ubi/cdev.c:1025
1 lock held by syz-executor.4/23563:
 #0: 000000008453d505 (ubi_devices_mutex){+.+.}, at: ctrl_cdev_ioctl+0x1b5/0x2b0 drivers/mtd/ubi/cdev.c:1050
1 lock held by syz-executor.4/23568:
 #0: 000000008453d505 (ubi_devices_mutex){+.+.}, at: ctrl_cdev_ioctl+0x213/0x2b0 drivers/mtd/ubi/cdev.c:1025
1 lock held by syz-executor.3/23565:
 #0: 000000008453d505 (ubi_devices_mutex){+.+.}, at: ctrl_cdev_ioctl+0x1b5/0x2b0 drivers/mtd/ubi/cdev.c:1050
1 lock held by syz-executor.3/23569:
 #0: 000000008453d505 (ubi_devices_mutex){+.+.}, at: ctrl_cdev_ioctl+0x213/0x2b0 drivers/mtd/ubi/cdev.c:1025

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

NMI backtrace for cpu 1
CPU: 1 PID: 1083 Comm: khungtaskd Not tainted 4.19.132-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+0x1fc/0x2fe lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1a6/0x1eb lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline]
 watchdog+0x991/0xe60 kernel/hung_task.c:287
 kthread+0x30b/0x410 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 3694 Comm: systemd-journal Not tainted 4.19.132-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__read_once_size include/linux/compiler.h:193 [inline]
RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:2316 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:2336 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:2390 [inline]
RIP: 0010:__lock_acquire+0xbb3/0x3ff0 kernel/locking/lockdep.c:3415
Code: 80 46 86 c8 61 48 b8 00 00 00 00 00 fc ff df 49 0f af cc 48 c1 e9 31 4c 8d 04 cd 80 68 3d 8b 4c 89 c2 48 c1 ea 03 80 3c 02 00 <0f> 85 83 25 00 00 48 8b 1c cd 80 68 3d 8b 48 85 db 74 55 48 83 eb
RSP: 0018:ffff888093e479c8 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: 6fc0139f2baac99d RCX: 0000000000007187
RDX: 1ffffffff1681e97 RSI: 000000006993aba4 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff8b40f4b8 R09: 0000000000000001
R10: ffff888093e3cbb0 R11: 0000000000000000 R12: 53ceec0cbf2791cb
R13: ffff888093e3c300 R14: ffff888093e3cbc8 R15: 0000000000000000
FS:  00007f2a7bacb8c0(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f40340057a0 CR3: 0000000094a20000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3907
 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:128 [inline]
 _raw_spin_lock_irq+0x5b/0x80 kernel/locking/spinlock.c:160
 spin_lock_irq include/linux/spinlock.h:354 [inline]
 ep_scan_ready_list+0x291/0x9a0 fs/eventpoll.c:710
 ep_send_events fs/eventpoll.c:1713 [inline]
 ep_poll+0x36f/0xcb0 fs/eventpoll.c:1840
 do_epoll_wait+0x1aa/0x200 fs/eventpoll.c:2198
 __do_sys_epoll_wait fs/eventpoll.c:2208 [inline]
 __se_sys_epoll_wait fs/eventpoll.c:2205 [inline]
 __x64_sys_epoll_wait+0x93/0xf0 fs/eventpoll.c:2205
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f2a7ad952e3
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:00007ffe21ca7fa8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8
RAX: ffffffffffffffda RBX: 000055f00063f200 RCX: 00007f2a7ad952e3
RDX: 0000000000000013 RSI: 00007ffe21ca7fb0 RDI: 0000000000000008
RBP: 00007ffe21ca81a0 R08: 00007ffe21ddc000 R09: 00000210d5a0c57f
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe21ca7fb0
R13: 0000000000000001 R14: ffffffffffffffff R15: 0005aa7d0692a092

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-19 2020/07/15 16:29 linux-4.19.y dce0f88600e4 ada108d0 .config log report syz