bisecting fixing commit since 6b6446efedb27c2766745a04f9b5d4449f51391d building syzkaller on cba33199be220cbf61f7c0c8223d88a25a913d6f testing commit 6b6446efedb27c2766745a04f9b5d4449f51391d with gcc (GCC) 8.4.1 20210217 kernel signature: 19e2f174da1b22c86e5afaf57993fb7845a606b33bad06b33d24c8e399756a3f run #0: crashed: possible deadlock in __get_super run #1: crashed: possible deadlock in __get_super run #2: crashed: possible deadlock in blkdev_put run #3: crashed: possible deadlock in __get_super run #4: crashed: possible deadlock in __get_super run #5: crashed: possible deadlock in blkdev_put run #6: crashed: possible deadlock in __get_super run #7: crashed: possible deadlock in blkdev_put run #8: crashed: possible deadlock in __get_super run #9: crashed: possible deadlock in blkdev_put run #10: crashed: possible deadlock in __get_super run #11: crashed: possible deadlock in __get_super run #12: crashed: possible deadlock in blkdev_put run #13: crashed: possible deadlock in __get_super run #14: crashed: INFO: task hung in blkdev_put 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 __get_super testing current HEAD 29c52025152bab4c557d8174da58f1a4c8e70438 testing commit 29c52025152bab4c557d8174da58f1a4c8e70438 with gcc (GCC) 8.4.1 20210217 kernel signature: 68c63f994b11d8039bbc8296931194e2434625c378bb6c8d76997f59a40bf189 run #0: crashed: INFO: task hung in __get_super run #1: crashed: INFO: task hung in __get_super run #2: crashed: INFO: task hung in __get_super 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 __get_super 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 blkdev_put revisions tested: 2, total time: 28m22.467182543s (build: 13m46.430341635s, test: 13m41.767855276s) the crash still happens on HEAD commit msg: Linux 4.14.221 crash: INFO: task hung in blkdev_put Bluetooth: hci5 command 0x0406 tx timeout Bluetooth: hci0 command 0x0406 tx timeout Bluetooth: hci3 command 0x0406 tx timeout Bluetooth: hci4 command 0x0406 tx timeout Bluetooth: hci2 command 0x0406 tx timeout INFO: task syz-executor.0:8979 blocked for more than 140 seconds. Not tainted 4.14.221-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D26296 8979 7658 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: 0033:0x466daa RSP: 002b:00007fd71c7a2fa8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 0000000000466daa RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fd71c7a3000 RBP: 00007fd71c7a3040 R08: 00007fd71c7a3040 R09: 0000000020000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000000 R13: 0000000020000100 R14: 00007fd71c7a3000 R15: 0000000020011100 INFO: task syz-executor.0:8986 blocked for more than 140 seconds. Not tainted 4.14.221-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28360 8986 7658 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: 0033:0x418e74 RSP: 002b:00007fd71c781ed0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00000000004be4b8 RCX: 0000000000418e74 RDX: 0000000000000002 RSI: 00007fd71c782000 RDI: 00000000ffffff9c RBP: 00007fd71c782000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000002 R13: 0000000000000004 R14: 0000000020000290 R15: 0000000000000006 INFO: task syz-executor.0:9014 blocked for more than 140 seconds. Not tainted 4.14.221-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28472 9014 7658 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: 0033:0x465889 RSP: 002b:00007fd71c761188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000055c050 RCX: 0000000000465889 RDX: 0000000020000280 RSI: 0000000000004c02 RDI: 0000000000000003 RBP: 00000000004af68d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000055c050 R13: 00007fff055a59cf R14: 00007fd71c761300 R15: 0000000000022000 INFO: task systemd-udevd:9016 blocked for more than 140 seconds. Not tainted 4.14.221-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. systemd-udevd D28344 9016 4319 0x00000124 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: 0033:0x7f6a2803e017 RSP: 002b:00007ffd9f3f0ba8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000562eb24d4390 RCX: 00007f6a2803e017 RDX: 0000000000000000 RSI: 0000000000005331 RDI: 000000000000000f RBP: 000000000000000f R08: 0000562eb24d3c70 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000004027e00 R13: 0000000000000000 R14: 0000000000000000 R15: 000000000000000f INFO: task syz-executor.1:9099 blocked for more than 140 seconds. Not tainted 4.14.221-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D27952 9099 7659 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: 0033:0x418e74 RSP: 002b:00007f838ac8bcc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000418e74 RDX: 0000000000000000 RSI: 00007f838ac8bd60 RDI: 00000000ffffff9c RBP: 00007f838ac8bd60 R08: 0000000000000000 R09: 0023706f6f6c2f76 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007ffee816dbff R14: 00007f838ac8c300 R15: 0000000000022000 INFO: task syz-executor.1:9119 blocked for more than 140 seconds. Not tainted 4.14.221-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28904 9119 7659 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: 0033:0x418e74 RSP: 002b:00007f838ac49cc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000418e74 RDX: 0000000000000000 RSI: 00007f838ac49d60 RDI: 00000000ffffff9c RBP: 00007f838ac49d60 R08: 0000000000000000 R09: 0023706f6f6c2f76 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007ffee816dbff R14: 00007f838ac4a300 R15: 0000000000022000 INFO: task syz-executor.2:9205 blocked for more than 140 seconds. Not tainted 4.14.221-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D29304 9205 7661 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: 0033:0x418e74 RSP: 002b:00007fca7ea57cc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000418e74 RDX: 0000000000000000 RSI: 00007fca7ea57d60 RDI: 00000000ffffff9c RBP: 00007fca7ea57d60 R08: 0000000000000000 R09: 0023706f6f6c2f76 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007ffc647dcaef R14: 00007fca7ea58300 R15: 0000000000022000 INFO: task syz-executor.2:9227 blocked for more than 140 seconds. Not tainted 4.14.221-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28904 9227 7661 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: 0033:0x418e74 RSP: 002b:00007fca7ea15cc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000418e74 RDX: 0000000000000000 RSI: 00007fca7ea15d60 RDI: 00000000ffffff9c RBP: 00007fca7ea15d60 R08: 0000000000000000 R09: 0023706f6f6c2f76 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007ffc647dcaef R14: 00007fca7ea16300 R15: 0000000000022000 INFO: task syz-executor.3:9208 blocked for more than 140 seconds. Not tainted 4.14.221-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28904 9208 7664 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: 0033:0x418e74 RSP: 002b:00007f72dba2ccc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000418e74 RDX: 0000000000000000 RSI: 00007f72dba2cd60 RDI: 00000000ffffff9c RBP: 00007f72dba2cd60 R08: 0000000000000000 R09: 0023706f6f6c2f76 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007fffc36db5bf R14: 00007f72dba2d300 R15: 0000000000022000 INFO: task syz-executor.3:9228 blocked for more than 140 seconds. Not tainted 4.14.221-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28904 9228 7664 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: 0033:0x418e74 RSP: 002b:00007f72db9eacc0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000418e74 RDX: 0000000000000000 RSI: 00007f72db9ead60 RDI: 00000000ffffff9c RBP: 00007f72db9ead60 R08: 0000000000000000 R09: 0023706f6f6c2f76 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007fffc36db5bf R14: 00007f72db9eb300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1530: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4548 1 lock held by in:imklog/7116: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0x8e/0xc0 fs/file.c:769 2 locks held by syz-executor.0/8979: #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.0/8986: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 3 locks held by syz-executor.0/9014: #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 systemd-udevd/9016: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [] lo_ioctl+0x8a/0x1c30 drivers/block/loop.c:1414 1 lock held by syz-executor.1/9099: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.1/9119: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.2/9205: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.2/9227: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.3/9208: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.3/9228: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.5/9239: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.5/9245: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x185/0xff0 fs/block_dev.c:1455 1 lock held by syz-executor.4/9262: #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 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1530 Comm: khungtaskd Not tainted 4.14.221-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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 7121 Comm: rs:main Q:Reg Not tainted 4.14.221-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8881d3a1e3c0 task.stack: ffff8881f2bd8000 RIP: 0010:io_is_direct include/linux/fs.h:3175 [inline] RIP: 0010:iocb_flags include/linux/fs.h:3202 [inline] RIP: 0010:init_sync_kiocb include/linux/fs.h:1928 [inline] RIP: 0010:new_sync_write fs/read_write.c:465 [inline] RIP: 0010:__vfs_write+0x1da/0x840 fs/read_write.c:482 RSP: 0018:ffff8881f2bdfc80 EFLAGS: 00000246 RAX: 0000000000008401 RBX: 1ffff1103e57bf95 RCX: ffff8881cf7496b0 RDX: ffff8881cf7498c0 RSI: 1ffff11039ee9318 RDI: ffff8881e62bfbb8 RBP: ffff8881f2bdfdf0 R08: 0000000000000561 R09: ffff8881e62bfa28 R10: 0000000000000028 R11: ffff8881d3a1e3c0 R12: ffff8881e62bfa00 R13: ffff8881f2bdfdc8 R14: 0000000000000002 R15: ffff8881f2bdfe80 FS: 00007f3b4ac7d700(0000) GS:ffff8881f6400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5af2187008 CR3: 00000001f3626001 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: vfs_write+0x150/0x4f0 fs/read_write.c:544 SYSC_write fs/read_write.c:590 [inline] SyS_write+0x100/0x250 fs/read_write.c:582 do_syscall_64+0x1c7/0x5b0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f3b4d6c11cd RSP: 002b:00007f3b4ac7c590 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f3b40026f10 RCX: 00007f3b4d6c11cd RDX: 0000000000000561 RSI: 00007f3b40026f10 RDI: 0000000000000009 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 00007f3b40026c90 R13: 00007f3b4ac7c5b0 R14: 00005558118f27c0 R15: 0000000000000561 Code: 85 34 05 00 00 49 8b 94 24 b8 01 00 00 48 b9 00 00 00 00 00 fc ff df 48 89 d6 48 c1 ee 03 80 3c 0e 00 0f 85 8b 04 00 00 48 8b 0a <48> ba 00 00 00 00 00 fc ff df 48 8d 79 0c 48 89 fe 48 c1 ee 03