netlink: 3 bytes leftover after parsing attributes in process `syz-executor.3'. INFO: task syz-executor.4:2135 blocked for more than 140 seconds. Not tainted 4.9.170+ #48 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D25528 2135 1 0x00000004 ffff8801d782df00 ffff8801cbd0dd80 ffff8801db621000 ffff8801cc165f00 ffff8801db621018 ffff8801a880fb28 ffffffff82801a4e ffff8801d782df00 ffff8801a880fc00 0000000000000046 ffff8801db6218f0 1ffff10035101f54 Call Trace: [<00000000119feb07>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<0000000053cd78b2>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<00000000ea6f8c45>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<00000000ea6f8c45>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<000000004f6e025a>] __lo_release drivers/block/loop.c:1642 [inline] [<000000004f6e025a>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665 [<000000008be6b583>] __blkdev_put+0x461/0x840 fs/block_dev.c:1606 [<00000000b09d7d72>] blkdev_put+0x88/0x560 fs/block_dev.c:1671 [<000000008d65b243>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1678 [<00000000c15db64c>] __fput+0x274/0x720 fs/file_table.c:208 [<0000000055f18f67>] ____fput+0x16/0x20 fs/file_table.c:244 [<000000007aba1fe9>] task_work_run+0x108/0x180 kernel/task_work.c:116 [<00000000b7469de5>] tracehook_notify_resume include/linux/tracehook.h:191 [inline] [<00000000b7469de5>] exit_to_usermode_loop+0x13b/0x160 arch/x86/entry/common.c:162 [<0000000026d9b087>] prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] [<0000000026d9b087>] syscall_return_slowpath arch/x86/entry/common.c:263 [inline] [<0000000026d9b087>] do_syscall_64+0x3f7/0x570 arch/x86/entry/common.c:290 [<00000000e18ea72b>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Showing all locks held in the system: 2 locks held by khungtaskd/24: #0: (rcu_read_lock){......}, at: [<00000000d9c6130a>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline] #0: (rcu_read_lock){......}, at: [<00000000d9c6130a>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263 #1: (tasklist_lock){.+.+..}, at: [<00000000d79c6de2>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4339 2 locks held by getty/2022: #0: (&tty->ldisc_sem){++++++}, at: [<00000000df3dbabf>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+...}, at: [<00000000ff0fe701>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 3 locks held by syz-executor.4/2135: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000ae426905>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587 #1: (loop_index_mutex){+.+.+.}, at: [<000000007b607d0b>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664 #2: (loop_ctl_mutex#2){+.+.+.}, at: [<000000004f6e025a>] __lo_release drivers/block/loop.c:1642 [inline] #2: (loop_ctl_mutex#2){+.+.+.}, at: [<000000004f6e025a>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665 2 locks held by syz-executor.1/3393: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000035cc943d>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000d256696d>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 2 locks held by syz-executor.2/18851: #0: (loop_ctl_mutex/1){+.+.+.}, at: [<0000000050f93a6a>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 #1: (&bdev->bd_mutex){+.+.+.}, at: [<0000000095854e10>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 1 lock held by blkid/18850: #0: (loop_ctl_mutex/1){+.+.+.}, at: [<0000000050f93a6a>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 1 lock held by blkid/18856: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000035cc943d>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 2 locks held by blkid/18859: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000035cc943d>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000d256696d>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.170+ #48 ffff8801d98d7cc8 ffffffff81b4fb21 0000000000000000 0000000000000000 0000000000000000 ffffffff81097401 dffffc0000000000 ffff8801d98d7d00 ffffffff81b5adbc 0000000000000000 0000000000000000 0000000000000000 Call Trace: [<0000000000fa49bf>] __dump_stack lib/dump_stack.c:15 [inline] [<0000000000fa49bf>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<000000005819a23e>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<000000003670d965>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<0000000049f70743>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<00000000bd69bfd1>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<00000000bd69bfd1>] check_hung_task kernel/hung_task.c:126 [inline] [<00000000bd69bfd1>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline] [<00000000bd69bfd1>] watchdog+0x670/0xaf0 kernel/hung_task.c:263 [<0000000076286493>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000b2b5719b>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff82810ac2