bisecting fixing commit since 5b7a52cd2eef952cee8a72512ef370bcdef46636 building syzkaller on 94942294277bf7550b12322d282159551521258b testing commit 5b7a52cd2eef952cee8a72512ef370bcdef46636 with gcc (GCC) 8.4.1 20210217 kernel signature: 889e437e35d52804b41b1b1addb9f275bba648d7bdfa549f5be4ed9baa563fb7 run #0: crashed: possible deadlock in __get_super run #1: crashed: possible deadlock in __get_super run #2: crashed: possible deadlock in __get_super run #3: crashed: possible deadlock in __get_super run #4: crashed: possible deadlock in __get_super run #5: crashed: possible deadlock in __get_super run #6: crashed: possible deadlock in __get_super run #7: crashed: possible deadlock in __get_super run #8: crashed: possible deadlock in __get_super run #9: crashed: possible deadlock in __get_super run #10: crashed: possible deadlock in __get_super run #11: crashed: possible deadlock in __get_super run #12: crashed: possible deadlock in __get_super run #13: crashed: possible deadlock in __get_super run #14: crashed: possible deadlock in __get_super run #15: crashed: INFO: task hung in blkdev_put run #16: crashed: INFO: task hung in blkdev_put run #17: crashed: INFO: task hung in blkdev_put run #18: crashed: INFO: task hung in blkdev_put run #19: crashed: INFO: task hung in blkdev_put testing current HEAD 670d6552eda8ff0c5f396d3d6f0174237917c66c testing commit 670d6552eda8ff0c5f396d3d6f0174237917c66c with gcc (GCC) 8.4.1 20210217 kernel signature: 7e53c437620fada3ced04173f77dca7a3807fee745f0bb925aa097633573b85a run #0: crashed: INFO: task hung in blkdev_put run #1: crashed: INFO: task hung in __get_super run #2: crashed: INFO: task hung in blkdev_put run #3: crashed: INFO: task hung in blkdev_put run #4: crashed: INFO: task hung in blkdev_put run #5: crashed: INFO: task hung in blkdev_put run #6: crashed: INFO: task hung in blkdev_put run #7: crashed: INFO: task hung in __get_super run #8: crashed: INFO: task hung in blkdev_put run #9: crashed: INFO: task hung in __get_super revisions tested: 2, total time: 28m5.51874132s (build: 13m59.602220817s, test: 13m44.617867052s) the crash still happens on HEAD commit msg: Linux 4.14.227 crash: INFO: task hung in __get_super Bluetooth: hci1 command 0x0406 tx timeout Bluetooth: hci4 command 0x0406 tx timeout Bluetooth: hci3 command 0x0406 tx timeout Bluetooth: hci0 command 0x0406 tx timeout Bluetooth: hci2 command 0x0406 tx timeout INFO: task syz-executor.3:9192 blocked for more than 140 seconds. Not tainted 4.14.227-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28472 9192 7649 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x1fb/0x390 kernel/locking/rwsem-xadd.c:309 call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94 __down_read arch/x86/include/asm/rwsem.h:66 [inline] down_read+0x49/0xb0 kernel/locking/rwsem.c:26 __get_super.part.2+0x190/0x260 fs/super.c:678 __get_super include/linux/spinlock.h:317 [inline] get_super+0x23/0x30 fs/super.c:707 fsync_bdev+0x13/0xb0 fs/block_dev.c:495 invalidate_partition+0x1f/0x40 block/genhd.c:1509 drop_partitions block/partition-generic.c:442 [inline] rescan_partitions+0xac/0x8c0 block/partition-generic.c:515 __blkdev_reread_part+0x12a/0x190 block/ioctl.c:173 blkdev_reread_part+0x20/0x40 block/ioctl.c:193 loop_reread_partitions+0x5d/0x70 drivers/block/loop.c:624 loop_set_status+0xb04/0x1070 drivers/block/loop.c:1193 loop_set_status_old+0x174/0x1c0 drivers/block/loop.c:1301 lo_ioctl+0x8c7/0x1c30 drivers/block/loop.c:1431 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x7c0/0x1760 block/ioctl.c:594 block_ioctl+0xd7/0x130 fs/block_dev.c:1893 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x180/0xfb0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x74/0x80 fs/ioctl.c:692 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x465849 RSP: 002b:00007f1c0ebd7188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000055c050 RCX: 0000000000465849 RDX: 0000000020000280 RSI: 0000000000004c02 RDI: 0000000000000003 RBP: 00000000004af675 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055c050 R13: 00007fff998f21ff R14: 00007f1c0ebd7300 R15: 0000000000022000 INFO: task syz-executor.0:9161 blocked for more than 140 seconds. Not tainted 4.14.227-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28344 9161 7651 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 blkdev_put+0x25/0x470 fs/block_dev.c:1826 blkdev_close+0x88/0xd0 fs/block_dev.c:1875 __fput+0x232/0x740 fs/file_table.c:210 ____fput+0x9/0x10 fs/file_table.c:244 task_work_run+0xe5/0x170 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x14a/0x190 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+0x416/0x5b0 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x418b5b RSP: 002b:00007ffe73691c70 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000418b5b RDX: 00000000000003e7 RSI: 0000001b31b2012c RDI: 0000000000000003 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000001b31b20134 R10: 000078be5bd52385 R11: 0000000000000293 R12: 000000000055c980 R13: 000000000000cfde R14: 000000000055c980 R15: 000000000055bfa8 INFO: task syz-executor.0:9166 blocked for more than 140 seconds. Not tainted 4.14.227-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D26656 9166 7651 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 blkdev_put+0x25/0x470 fs/block_dev.c:1826 release_journal_dev fs/reiserfs/journal.c:2598 [inline] free_journal_ram+0x340/0x4c0 fs/reiserfs/journal.c:1903 do_journal_release fs/reiserfs/journal.c:1969 [inline] journal_release_error+0x74/0xa0 fs/reiserfs/journal.c:1987 reiserfs_fill_super+0x1323/0x26f0 fs/reiserfs/super.c:2228 mount_bdev+0x26f/0x330 fs/super.c:1134 get_super_block+0x10/0x20 fs/reiserfs/super.c:2609 mount_fs+0x7f/0x270 fs/super.c:1237 vfs_kern_mount.part.9+0x58/0x3c0 fs/namespace.c:1046 vfs_kern_mount fs/namespace.c:1036 [inline] do_new_mount fs/namespace.c:2549 [inline] do_mount+0x352/0x2af0 fs/namespace.c:2879 SYSC_mount fs/namespace.c:3095 [inline] SyS_mount+0xb1/0xd0 fs/namespace.c:3072 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x466d6a RSP: 002b:00007fd2efd6cfa8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 0000000000466d6a RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fd2efd6d000 RBP: 00007fd2efd6d040 R08: 00007fd2efd6d040 R09: 0000000020000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000000 R13: 0000000020000100 R14: 00007fd2efd6d000 R15: 0000000020011100 INFO: task syz-executor.2:9195 blocked for more than 140 seconds. Not tainted 4.14.227-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D29384 9195 7657 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 lo_ioctl+0x8a/0x1c30 drivers/block/loop.c:1414 __blkdev_driver_ioctl block/ioctl.c:297 [inline] blkdev_ioctl+0x7c0/0x1760 block/ioctl.c:594 block_ioctl+0xd7/0x130 fs/block_dev.c:1893 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x180/0xfb0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x74/0x80 fs/ioctl.c:692 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x465849 RSP: 002b:00007f8aafa0e188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000055bf00 RCX: 0000000000465849 RDX: 0000000020000280 RSI: 0000000000004c02 RDI: 0000000000000003 RBP: 00000000004af675 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055bf00 R13: 00007ffe88a8b15f R14: 00007f8aafa0e300 R15: 0000000000022000 INFO: task syz-executor.2:9211 blocked for more than 140 seconds. Not tainted 4.14.227-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28904 9211 7657 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 blkdev_get+0x265/0x890 fs/block_dev.c:1611 blkdev_open+0x19f/0x200 fs/block_dev.c:1772 do_dentry_open+0x3e4/0xde0 fs/open.c:777 vfs_open+0xfc/0x240 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0xb6f/0x2760 fs/namei.c:3569 do_filp_open+0x16b/0x220 fs/namei.c:3603 do_sys_open+0x1d0/0x350 fs/open.c:1081 SYSC_openat fs/open.c:1108 [inline] SyS_openat+0xf/0x20 fs/open.c:1102 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x418e34 RSP: 002b:00007f8aaf9cbcc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000418e34 RDX: 0000000000000000 RSI: 00007f8aaf9cbd60 RDI: 00000000ffffff9c RBP: 00007f8aaf9cbd60 R08: 0000000000000000 R09: 0023706f6f6c2f76 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007ffe88a8b15f R14: 00007f8aaf9cc300 R15: 0000000000022000 INFO: task syz-executor.1:9212 blocked for more than 140 seconds. Not tainted 4.14.227-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28936 9212 7656 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 blkdev_get+0x265/0x890 fs/block_dev.c:1611 blkdev_open+0x19f/0x200 fs/block_dev.c:1772 do_dentry_open+0x3e4/0xde0 fs/open.c:777 vfs_open+0xfc/0x240 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0xb6f/0x2760 fs/namei.c:3569 do_filp_open+0x16b/0x220 fs/namei.c:3603 do_sys_open+0x1d0/0x350 fs/open.c:1081 SYSC_openat fs/open.c:1108 [inline] SyS_openat+0xf/0x20 fs/open.c:1102 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x418e34 RSP: 002b:00007fe230535cc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000418e34 RDX: 0000000000000000 RSI: 00007fe230535d60 RDI: 00000000ffffff9c RBP: 00007fe230535d60 R08: 0000000000000000 R09: 0023706f6f6c2f76 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007ffc2057d06f R14: 00007fe230536300 R15: 0000000000022000 INFO: task syz-executor.1:9228 blocked for more than 140 seconds. Not tainted 4.14.227-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28904 9228 7656 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 blkdev_get+0x265/0x890 fs/block_dev.c:1611 blkdev_open+0x19f/0x200 fs/block_dev.c:1772 do_dentry_open+0x3e4/0xde0 fs/open.c:777 vfs_open+0xfc/0x240 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0xb6f/0x2760 fs/namei.c:3569 do_filp_open+0x16b/0x220 fs/namei.c:3603 do_sys_open+0x1d0/0x350 fs/open.c:1081 SYSC_openat fs/open.c:1108 [inline] SyS_openat+0xf/0x20 fs/open.c:1102 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x418e34 RSP: 002b:00007fe2304f3cc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000418e34 RDX: 0000000000000000 RSI: 00007fe2304f3d60 RDI: 00000000ffffff9c RBP: 00007fe2304f3d60 R08: 0000000000000000 R09: 0023706f6f6c2f76 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007ffc2057d06f R14: 00007fe2304f4300 R15: 0000000000022000 INFO: task syz-executor.5:9225 blocked for more than 140 seconds. Not tainted 4.14.227-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28904 9225 7652 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 blkdev_get+0x265/0x890 fs/block_dev.c:1611 blkdev_open+0x19f/0x200 fs/block_dev.c:1772 do_dentry_open+0x3e4/0xde0 fs/open.c:777 vfs_open+0xfc/0x240 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0xb6f/0x2760 fs/namei.c:3569 do_filp_open+0x16b/0x220 fs/namei.c:3603 do_sys_open+0x1d0/0x350 fs/open.c:1081 SYSC_openat fs/open.c:1108 [inline] SyS_openat+0xf/0x20 fs/open.c:1102 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x418e34 RSP: 002b:00007f1e565f1cc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000418e34 RDX: 0000000000000000 RSI: 00007f1e565f1d60 RDI: 00000000ffffff9c RBP: 00007f1e565f1d60 R08: 0000000000000000 R09: 0023706f6f6c2f76 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007ffc7264af8f R14: 00007f1e565f2300 R15: 0000000000022000 INFO: task syz-executor.5:9242 blocked for more than 140 seconds. Not tainted 4.14.227-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28904 9242 7652 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 blkdev_get+0x265/0x890 fs/block_dev.c:1611 blkdev_open+0x19f/0x200 fs/block_dev.c:1772 do_dentry_open+0x3e4/0xde0 fs/open.c:777 vfs_open+0xfc/0x240 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0xb6f/0x2760 fs/namei.c:3569 do_filp_open+0x16b/0x220 fs/namei.c:3603 do_sys_open+0x1d0/0x350 fs/open.c:1081 SYSC_openat fs/open.c:1108 [inline] SyS_openat+0xf/0x20 fs/open.c:1102 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x418e34 RSP: 002b:00007f1e565afcc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000418e34 RDX: 0000000000000000 RSI: 00007f1e565afd60 RDI: 00000000ffffff9c RBP: 00007f1e565afd60 R08: 0000000000000000 R09: 0023706f6f6c2f76 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007ffc7264af8f R14: 00007f1e565b0300 R15: 0000000000022000 INFO: task syz-executor.4:9267 blocked for more than 140 seconds. Not tainted 4.14.227-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28904 9267 7655 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x824/0x1ee0 kernel/sched/core.c:3384 schedule+0x7f/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x519/0x1490 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 blkdev_get+0x265/0x890 fs/block_dev.c:1611 blkdev_open+0x19f/0x200 fs/block_dev.c:1772 do_dentry_open+0x3e4/0xde0 fs/open.c:777 vfs_open+0xfc/0x240 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0xb6f/0x2760 fs/namei.c:3569 do_filp_open+0x16b/0x220 fs/namei.c:3603 do_sys_open+0x1d0/0x350 fs/open.c:1081 SYSC_openat fs/open.c:1108 [inline] SyS_openat+0xf/0x20 fs/open.c:1102 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x418e34 RSP: 002b:00007f267e2facc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000418e34 RDX: 0000000000000000 RSI: 00007f267e2fad60 RDI: 00000000ffffff9c RBP: 00007f267e2fad60 R08: 0000000000000000 R09: 0023706f6f6c2f76 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007fff39b1f7ff R14: 00007f267e2fb300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1522: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4548 1 lock held by systemd-journal/4306: #0: (rcu_read_lock){....}, at: [] devkmsg_read+0xb6/0xa00 kernel/printk/printk.c:831 3 locks held by syz-executor.3/9192: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c30 drivers/block/loop.c:1414 #1: (&bdev->bd_mutex){+.+.}, at: [] blkdev_reread_part+0x18/0x40 block/ioctl.c:192 #2: (&type->s_umount_key#48){.+.+}, at: [] __get_super.part.2+0x190/0x260 fs/super.c:678 1 lock held by syz-executor.0/9161: #0: (&bdev->bd_mutex){+.+.}, at: [] blkdev_put+0x25/0x470 fs/block_dev.c:1826 2 locks held by syz-executor.0/9166: #0: (&type->s_umount_key#22/1){+.+.}, at: [] alloc_super fs/super.c:251 [inline] #0: (&type->s_umount_key#22/1){+.+.}, at: [] sget_userns+0x429/0xb40 fs/super.c:516 #1: (&bdev->bd_mutex){+.+.}, at: [] blkdev_put+0x25/0x470 fs/block_dev.c:1826 1 lock held by syz-executor.2/9195: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c30 drivers/block/loop.c:1414 1 lock held by syz-executor.2/9211: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.1/9212: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.1/9228: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.5/9225: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.5/9242: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.4/9267: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.4/9274: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1522 Comm: khungtaskd Not tainted 4.14.227-syzkaller #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+0x14b/0x1e7 lib/dump_stack.c:58 nmi_cpu_backtrace.cold.0+0x3c/0x78 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xf6/0x120 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+0x51b/0xa70 kernel/hung_task.c:274 kthread+0x338/0x400 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 skipped: idling at pc 0xffffffff87343c92