INFO: task syz.3.206:6763 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.206 state:D stack:28480 pid:6763 tgid:6760 ppid:5834 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7026 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7083 __mutex_lock_common kernel/locking/mutex.c:676 [inline] __mutex_lock+0x818/0x1060 kernel/locking/mutex.c:760 blk_trace_remove kernel/trace/blktrace.c:406 [inline] blk_trace_ioctl+0x23a/0x280 kernel/trace/blktrace.c:727 blkdev_common_ioctl+0xf29/0x2470 block/ioctl.c:630 blkdev_ioctl+0x1cb/0x6d0 block/ioctl.c:699 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc7c1d8eec9 RSP: 002b:00007fc7c2c4d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fc7c1fe6180 RCX: 00007fc7c1d8eec9 RDX: 0000000000000000 RSI: 0000000000001276 RDI: 0000000000000006 RBP: 00007fc7c1e11f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc7c1fe6218 R14: 00007fc7c1fe6180 R15: 00007fffd44a5578 Showing all locks held in the system: 2 locks held by kworker/1:0H/25: 1 lock held by khungtaskd/31: #0: ffffffff8e1c34a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e1c34a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8e1c34a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775 5 locks held by kworker/1:1/44: #0: ffff888020ee3d48 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3238 #1: ffffc90000b47d10 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3239 #2: ffff888029b94198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] #2: ffff888029b94198 (&dev->mutex){....}-{4:4}, at: hub_event+0x1c0/0x4fe0 drivers/usb/core/hub.c:5898 #3: ffff888029b97518 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3251 [inline] #3: ffff888029b97518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5463 [inline] #3: ffff888029b97518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5706 [inline] #3: ffff888029b97518 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5870 [inline] #3: ffff888029b97518 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x2981/0x4fe0 drivers/usb/core/hub.c:5952 #4: ffff8880293b5268 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline] #4: ffff8880293b5268 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5706 [inline] #4: ffff8880293b5268 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5870 [inline] #4: ffff8880293b5268 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x29aa/0x4fe0 drivers/usb/core/hub.c:5952 2 locks held by getty/5583: #0: ffff888034de20a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222 3 locks held by syz.3.206/6762: 1 lock held by syz.3.206/6763: #0: ffff888143b6a698 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_remove kernel/trace/blktrace.c:406 [inline] #0: ffff888143b6a698 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_ioctl+0x23a/0x280 kernel/trace/blktrace.c:727 2 locks held by syz.0.776/8718: #0: ffffffff8fec80c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8fec80c8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3436 #1: ffffffff8e1cea38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x284/0x3c0 kernel/rcu/tree_exp.h:311 2 locks held by syz.0.776/8722: 1 lock held by syz.5.787/8741: #0: ffffffff8fec80c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8fec80c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnetlink_rcv_msg+0x371/0xe90 net/core/rtnetlink.c:6952 3 locks held by syz-executor/8742: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0xf0e/0x1260 kernel/hung_task.c:491 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 8742 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:check_preemption_disabled+0x2e/0xe0 lib/smp_processor_id.c:19 Code: 48 83 ec 08 65 8b 1d 55 99 2a 08 65 8b 05 4a 99 2a 08 a9 ff ff ff 7f 74 0f 48 83 c4 08 89 d8 5b 5d 41 5c c3 cc cc cc cc 9c 58 c4 02 74 ea 48 89 fd 65 48 8b 05 0a 99 2a 08 f6 40 2f 04 74 09 RSP: 0018:ffffc90003cc7710 EFLAGS: 00000046 RAX: 0000000000000046 RBX: 0000000000000000 RCX: ffffc90003cc7744 RDX: 0000000000000000 RSI: ffffffff8daa81e2 RDI: ffffffff8bd007c0 RBP: ffffc90003cc77e0 R08: 8f98732f2e8fc3da R09: 0000000000000001 R10: 0000000000000003 R11: 0000000000000000 R12: ffffffff8217e30f R13: 0000000000000283 R14: ffff8881a1294900 R15: 000000000000000d FS: 0000555558eb2500(0000) GS:ffff888124e71000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3ef73b6c60 CR3: 000000003446b000 CR4: 00000000003526f0 Call Trace: lockdep_recursion_inc kernel/locking/lockdep.c:465 [inline] lock_release+0x9c/0x2f0 kernel/locking/lockdep.c:5888 might_alloc include/linux/sched/mm.h:319 [inline] slab_pre_alloc_hook mm/slub.c:4142 [inline] slab_alloc_node mm/slub.c:4220 [inline] kmem_cache_alloc_lru_noprof+0x5f/0x3b0 mm/slub.c:4259 proc_alloc_inode+0x25/0x200 fs/proc/inode.c:57 alloc_inode+0x64/0x240 fs/inode.c:346 new_inode+0x22/0x1c0 fs/inode.c:1145 proc_pid_make_inode+0x22/0x160 fs/proc/base.c:1953 proc_pident_instantiate+0x85/0x310 fs/proc/base.c:2694 proc_pident_lookup+0x1f5/0x270 fs/proc/base.c:2729 lookup_open.isra.0+0x4da/0x1580 fs/namei.c:3774 open_last_lookups fs/namei.c:3895 [inline] path_openat+0x893/0x2cb0 fs/namei.c:4131 do_filp_open+0x20b/0x470 fs/namei.c:4161 do_sys_openat2+0x11b/0x1d0 fs/open.c:1435 do_sys_open fs/open.c:1450 [inline] __do_sys_openat fs/open.c:1466 [inline] __se_sys_openat fs/open.c:1461 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1461 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3ef738d710 Code: 48 89 44 24 20 75 93 44 89 54 24 0c e8 69 95 02 00 44 8b 54 24 0c 89 da 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 89 44 24 0c e8 bc 95 02 00 8b 44 RSP: 002b:00007ffd988c2530 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000080001 RCX: 00007f3ef738d710 RDX: 0000000000080001 RSI: 00007f3ef7413818 RDI: 00000000ffffff9c RBP: 00007f3ef7413818 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000004 R13: 00007ffd988c25d0 R14: 0000000000046a44 R15: 00007ffd988c2b40