INFO: task syz-executor.0:1838 blocked for more than 140 seconds. Not tainted 4.14.123+ #2 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D25496 1838 1 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3498 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893 blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 loop_reread_partitions+0x72/0x80 drivers/block/loop.c:614 loop_clr_fd+0x828/0xac0 drivers/block/loop.c:1068 lo_ioctl+0x460/0x1a30 drivers/block/loop.c:1414 INFO: task syz-executor.1:1839 blocked for more than 140 seconds. Not tainted 4.14.123+ #2 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D25640 1839 1 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3498 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893 lo_open+0x19/0xb0 drivers/block/loop.c:1623 __blkdev_get+0x267/0xf90 fs/block_dev.c:1472 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770 do_dentry_open+0x44e/0xdf0 fs/open.c:770 vfs_open+0x105/0x230 fs/open.c:884 do_last fs/namei.c:3455 [inline] path_openat+0xb6b/0x2b70 fs/namei.c:3597 do_filp_open+0x1a1/0x280 fs/namei.c:3631 do_sys_open+0x2ca/0x590 fs/open.c:1077 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292 INFO: task syz-executor.5:1842 blocked for more than 140 seconds. Not tainted 4.14.123+ #2 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D25144 1842 1 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3498 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893 lo_open+0x19/0xb0 drivers/block/loop.c:1623 __blkdev_get+0x267/0xf90 fs/block_dev.c:1472 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770 do_dentry_open+0x44e/0xdf0 fs/open.c:770 vfs_open+0x105/0x230 fs/open.c:884 do_last fs/namei.c:3455 [inline] path_openat+0xb6b/0x2b70 fs/namei.c:3597 do_filp_open+0x1a1/0x280 fs/namei.c:3631 do_sys_open+0x2ca/0x590 fs/open.c:1077 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292 INFO: task syz-executor.3:1846 blocked for more than 140 seconds. Not tainted 4.14.123+ #2 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D24928 1846 1 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3498 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893 lo_open+0x19/0xb0 drivers/block/loop.c:1623 __blkdev_get+0x267/0xf90 fs/block_dev.c:1472 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770 do_dentry_open+0x44e/0xdf0 fs/open.c:770 vfs_open+0x105/0x230 fs/open.c:884 do_last fs/namei.c:3455 [inline] path_openat+0xb6b/0x2b70 fs/namei.c:3597 do_filp_open+0x1a1/0x280 fs/namei.c:3631 do_sys_open+0x2ca/0x590 fs/open.c:1077 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292 INFO: task syz-executor.4:1849 blocked for more than 140 seconds. Not tainted 4.14.123+ #2 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D25480 1849 1 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3498 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893 lo_open+0x19/0xb0 drivers/block/loop.c:1623 __blkdev_get+0x267/0xf90 fs/block_dev.c:1472 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770 do_dentry_open+0x44e/0xdf0 fs/open.c:770 vfs_open+0x105/0x230 fs/open.c:884 do_last fs/namei.c:3455 [inline] path_openat+0xb6b/0x2b70 fs/namei.c:3597 do_filp_open+0x1a1/0x280 fs/namei.c:3631 do_sys_open+0x2ca/0x590 fs/open.c:1077 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292 INFO: task syz-executor.2:3303 blocked for more than 140 seconds. Not tainted 4.14.123+ #2 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D27936 3303 1841 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3498 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893 loop_control_ioctl+0x183/0x300 drivers/block/loop.c:1996 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292 INFO: task blkid:3310 blocked for more than 140 seconds. Not tainted 4.14.123+ #2 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blkid D29248 3310 284 0x00000004 Call Trace: schedule+0x92/0x1c0 kernel/sched/core.c:3498 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3556 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893 lo_open+0x19/0xb0 drivers/block/loop.c:1623 __blkdev_get+0x963/0xf90 fs/block_dev.c:1537 blkdev_get+0x97/0x8b0 fs/block_dev.c:1612 blkdev_open+0x1cc/0x250 fs/block_dev.c:1770 do_dentry_open+0x44e/0xdf0 fs/open.c:770 vfs_open+0x105/0x230 fs/open.c:884 do_last fs/namei.c:3455 [inline] path_openat+0xb6b/0x2b70 fs/namei.c:3597 do_filp_open+0x1a1/0x280 fs/namei.c:3631 do_sys_open+0x2ca/0x590 fs/open.c:1077 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292 Showing all locks held in the system: 1 lock held by khungtaskd/23: #0: (tasklist_lock){.+.+}, at: [<000000001ca3e4a0>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4541 2 locks held by getty/1757: #0: (&tty->ldisc_sem){++++}, at: [<000000008d8d8d9d>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000e0ddfe07>] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.0/1838: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<000000008ae51797>] lo_ioctl+0x86/0x1a30 drivers/block/loop.c:1404 #1: (&bdev->bd_mutex){+.+.}, at: [<00000000146c05df>] blkdev_reread_part+0x1b/0x40 block/ioctl.c:192 2 locks held by syz-executor.1/1839: #0: (&bdev->bd_mutex){+.+.}, at: [<0000000000fd6379>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000471ed217>] lo_open+0x19/0xb0 drivers/block/loop.c:1623 2 locks held by syz-executor.5/1842: #0: (&bdev->bd_mutex){+.+.}, at: [<0000000000fd6379>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000471ed217>] lo_open+0x19/0xb0 drivers/block/loop.c:1623 2 locks held by syz-executor.3/1846: #0: (&bdev->bd_mutex){+.+.}, at: [<0000000000fd6379>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000471ed217>] lo_open+0x19/0xb0 drivers/block/loop.c:1623 2 locks held by syz-executor.4/1849: #0: (&bdev->bd_mutex){+.+.}, at: [<0000000000fd6379>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000471ed217>] lo_open+0x19/0xb0 drivers/block/loop.c:1623 2 locks held by syz-executor.2/3303: #0: (loop_index_mutex){+.+.}, at: [<0000000022d575d5>] loop_control_ioctl+0x71/0x300 drivers/block/loop.c:1982 #1: (&lo->lo_ctl_mutex#2){+.+.}, at: [<00000000a5c72320>] loop_control_ioctl+0x183/0x300 drivers/block/loop.c:1996 2 locks held by blkid/3310: #0: (&bdev->bd_mutex){+.+.}, at: [<0000000000fd6379>] __blkdev_get+0xf3/0xf90 fs/block_dev.c:1457 #1: (loop_index_mutex){+.+.}, at: [<00000000471ed217>] lo_open+0x19/0xb0 drivers/block/loop.c:1623 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 23 Comm: khungtaskd Not tainted 4.14.123+ #2 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x10e lib/dump_stack.c:53 nmi_cpu_backtrace.cold+0x47/0x86 lib/nmi_backtrace.c:101 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 1627 Comm: rs:main Q:Reg Not tainted 4.14.123+ #2 task: 00000000ccb21110 task.stack: 00000000c72474eb RIP: 0010:unwind_next_frame+0x19c/0x1810 arch/x86/kernel/unwind_orc.c:348 RSP: 0018:ffff8881d48ff560 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff8881d48ff630 RCX: 1ffff1103a91fecf RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff8881d49b1128 RBP: 1ffff1103a91feb3 R08: 0000000000000001 R09: ffff8881d48ffe68 R10: ffff8881d48ff665 R11: 000000000001c033 R12: 0000000000000000 R13: ffff8881d48ff668 R14: ffff8881d48ff678 R15: 0000000000000001 FS: 00007f2c37350700(0000) GS:ffff8881dbb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c431899010 CR3: 00000001d5122002 CR4: 00000000001606a0 Call Trace: __save_stack_trace+0x7a/0xf0 arch/x86/kernel/stacktrace.c:44 save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc.part.0+0x4f/0xd0 mm/kasan/kasan.c:551 slab_post_alloc_hook mm/slab.h:442 [inline] slab_alloc_node mm/slub.c:2723 [inline] slab_alloc mm/slub.c:2731 [inline] kmem_cache_alloc+0xd2/0x2d0 mm/slub.c:2736 mempool_alloc+0x126/0x300 mm/mempool.c:330 bio_alloc_bioset+0x379/0x660 block/bio.c:486 bio_alloc include/linux/bio.h:417 [inline] blkdev_issue_flush+0xeb/0x320 block/blk-flush.c:527 ext4_sync_file+0xb76/0x1270 fs/ext4/fsync.c:157 vfs_fsync_range+0x106/0x260 fs/sync.c:196 generic_write_sync include/linux/fs.h:2694 [inline] ext4_file_write_iter+0x83c/0xd60 fs/ext4/file.c:275 call_write_iter include/linux/fs.h:1785 [inline] new_sync_write fs/read_write.c:471 [inline] __vfs_write+0x401/0x5a0 fs/read_write.c:484 vfs_write+0x17f/0x4d0 fs/read_write.c:546 SYSC_write fs/read_write.c:593 [inline] SyS_write+0xc0/0x1a0 fs/read_write.c:585 do_syscall_64+0x19b/0x510 arch/x86/entry/common.c:292 Code: e2 07 38 d0 7f 08 84 c0 0f 85 aa 06 00 00 4c 8d 73 48 0f b6 43 35 48 ba 00 00 00 00 00 fc ff df 4c 89 f1 48 c1 e9 03 80 3c 11 00 <0f> 85 29 10 00 00 4c 8b 63 48 3c 01 49 83 dc 00 80 3d 1d 75 db