INFO: task syz-executor.1:5337 blocked for more than 143 seconds. Not tainted 5.16.0-rc1-next-20211118-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.1 state:D stack:27400 pid: 5337 ppid: 21551 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:4987 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6268 schedule+0xd2/0x260 kernel/sched/core.c:6341 blk_mq_freeze_queue_wait+0x112/0x160 block/blk-mq.c:178 __loop_clr_fd+0x1ae/0x1070 drivers/block/loop.c:1122 loop_clr_fd drivers/block/loop.c:1237 [inline] lo_ioctl+0x398/0x17c0 drivers/block/loop.c:1562 blkdev_ioctl+0x37a/0x800 block/ioctl.c:609 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f870e1e78a7 RSP: 002b:00007f870b75cfa8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000200003c0 RCX: 00007f870e1e78a7 RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000004 RBP: 00007f870b75d6bc R08: 00007f870b75d040 R09: 0000000020000240 R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff R13: 0000000000000016 R14: 00007f870b75d000 R15: 0000000020000400 Showing all locks held in the system: 1 lock held by khungtaskd/26: #0: ffffffff8bb83ba0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458 2 locks held by systemd-udevd/2969: #0: ffff88801baed918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev.part.0+0x9b/0xb50 block/bdev.c:819 #1: ffff88801bae9360 (&lo->lo_mutex){+.+.}-{3:3}, at: lo_open+0x75/0x120 drivers/block/loop.c:1733 1 lock held by in:imklog/6232: #0: ffff88807b0bd270 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990 1 lock held by syz-executor.1/5337: #0: ffff88801bae9360 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x7a/0x1070 drivers/block/loop.c:1106 1 lock held by syz-executor.1/5395: #0: ffff88801baed918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev.part.0+0x9b/0xb50 block/bdev.c:819 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 26 Comm: khungtaskd Not tainted 5.16.0-rc1-next-20211118-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:254 [inline] watchdog+0xcb7/0xed0 kernel/hung_task.c:339 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 10174 Comm: kworker/0:12 Not tainted 5.16.0-rc1-next-20211118-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events nsim_dev_trap_report_work RIP: 0010:preempt_count_sub+0x5f/0x150 kernel/sched/core.c:5486 Code: fc 0e 85 c9 75 1b 65 8b 05 1e 7e b2 7e 89 c2 81 e2 ff ff ff 7f 39 da 7c 13 81 fb fe 00 00 00 76 63 f7 db 65 01 1d 01 7e b2 7e <5b> c3 e8 fa 1d 84 02 85 c0 74 f5 48 c7 c0 08 1c 91 8d 48 ba 00 00 RSP: 0018:ffffc9000e64f648 EFLAGS: 00000293 RAX: 0000000080000002 RBX: 00000000ffffffff RCX: 0000000000000000 RDX: 0000000000000002 RSI: ffffc9000e64f808 RDI: 0000000000000001 RBP: ffffc9000e64f818 R08: ffffffff8e0ae0e2 R09: 0000000000000001 R10: fffff52001cc9efb R11: 000000000008808a R12: ffffc9000e648000 R13: ffffc9000e64f7b5 R14: ffffc9000e64f780 R15: ffffc9000e64f7b4 FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f406d31d5e8 CR3: 0000000019347000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: unwind_next_frame+0xee1/0x1ce0 arch/x86/kernel/unwind_orc.c:624 __unwind_start+0x51b/0x800 arch/x86/kernel/unwind_orc.c:712 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0x5c/0xe0 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x1e/0x50 mm/kasan/common.c:38 kasan_set_track+0x21/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xff/0x130 mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:1723 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1749 slab_free mm/slub.c:3513 [inline] kfree+0xf6/0x560 mm/slub.c:4561 skb_free_head net/core/skbuff.c:655 [inline] skb_release_data+0x65a/0x790 net/core/skbuff.c:677 skb_release_all net/core/skbuff.c:742 [inline] __kfree_skb net/core/skbuff.c:756 [inline] consume_skb net/core/skbuff.c:912 [inline] consume_skb+0xc2/0x160 net/core/skbuff.c:906 nsim_dev_trap_report drivers/net/netdevsim/dev.c:818 [inline] nsim_dev_trap_report_work+0x85d/0xbc0 drivers/net/netdevsim/dev.c:843 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 85 c9 test %ecx,%ecx 2: 75 1b jne 0x1f 4: 65 8b 05 1e 7e b2 7e mov %gs:0x7eb27e1e(%rip),%eax # 0x7eb27e29 b: 89 c2 mov %eax,%edx d: 81 e2 ff ff ff 7f and $0x7fffffff,%edx 13: 39 da cmp %ebx,%edx 15: 7c 13 jl 0x2a 17: 81 fb fe 00 00 00 cmp $0xfe,%ebx 1d: 76 63 jbe 0x82 1f: f7 db neg %ebx 21: 65 01 1d 01 7e b2 7e add %ebx,%gs:0x7eb27e01(%rip) # 0x7eb27e29 * 28: 5b pop %rbx <-- trapping instruction 29: c3 retq 2a: e8 fa 1d 84 02 callq 0x2841e29 2f: 85 c0 test %eax,%eax 31: 74 f5 je 0x28 33: 48 c7 c0 08 1c 91 8d mov $0xffffffff8d911c08,%rax 3a: 48 rex.W 3b: ba .byte 0xba