INFO: task udevd:5216 blocked for more than 143 seconds. Not tainted 6.12.0-rc6-syzkaller-00153-g237d4e0f4113 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:udevd state:D stack:26608 pid:5216 tgid:5216 ppid:2861 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5328 [inline] __schedule+0x1042/0x34b0 kernel/sched/core.c:6690 __schedule_loop kernel/sched/core.c:6767 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6782 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6839 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752 device_lock include/linux/device.h:1014 [inline] uevent_show+0x188/0x3b0 drivers/base/core.c:2736 dev_attr_show+0x53/0xe0 drivers/base/core.c:2430 sysfs_kf_seq_show+0x23e/0x410 fs/sysfs/file.c:59 seq_read_iter+0x4f4/0x12b0 fs/seq_file.c:230 kernfs_fop_read_iter+0x414/0x580 fs/kernfs/file.c:279 new_sync_read fs/read_write.c:488 [inline] vfs_read+0x87f/0xbe0 fs/read_write.c:569 ksys_read+0x12f/0x260 fs/read_write.c:712 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa07d314b6a RSP: 002b:00007ffdf0df69e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 000055b5e9f8ca80 RCX: 00007fa07d314b6a RDX: 0000000000001000 RSI: 000055b5ea06a610 RDI: 0000000000000008 RBP: 000055b5e9f8ca80 R08: 0000000000000008 R09: 0000000000000000 R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000003fff R14: 00007ffdf0df6ec8 R15: 000000000000000a Showing all locks held in the system: 5 locks held by kworker/0:0/8: 1 lock held by khungtaskd/30: #0: ffffffff88ebb140 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff88ebb140 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff88ebb140 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6720 3 locks held by kworker/0:2/1149: 2 locks held by getty/2919: #0: ffff8881083cf0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc900000432f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211 6 locks held by kworker/1:2/2922: #0: ffff8881062ec148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x129b/0x1ba0 kernel/workqueue.c:3204 #1: ffffc900005dfd80 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3205 #2: ffff88810ab89190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1014 [inline] #2: ffff88810ab89190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1be/0x4f40 drivers/usb/core/hub.c:5849 #3: ffffffff88ea8840 (console_lock){+.+.}-{0:0} , at: swake_up_one+0x1a/0x1b0 kernel/sched/swait.c:51 #4: ffffffff88ea88b0 (console_srcu){....}-{0:0} , at: rcu_try_lock_acquire include/linux/rcupdate.h:342 [inline] , at: srcu_read_lock_nmisafe include/linux/srcu.h:267 [inline] , at: console_srcu_read_lock kernel/printk/printk.c:288 [inline] , at: console_flush_all+0x159/0xc60 kernel/printk/printk.c:3157 #5: ffffffff93556f58 ( &obj_hash[i].lock){-.-.}-{2:2} , at: rcu_try_lock_acquire include/linux/rcupdate.h:342 [inline] , at: srcu_read_lock_nmisafe include/linux/srcu.h:267 [inline] , at: console_srcu_read_lock kernel/printk/printk.c:288 [inline] , at: console_flush_all+0x159/0xc60 kernel/printk/printk.c:3157 4 locks held by udevd/5216: #0: ffff8881118b4668 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xd8/0x12b0 fs/seq_file.c:182 #1: ffff88810ff2c488 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154 #2: ffff888116b39008 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155 #3: ffff88811337e190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1014 [inline] #3: ffff88811337e190 (&dev->mutex){....}-{3:3}, at: uevent_show+0x188/0x3b0 drivers/base/core.c:2736 4 locks held by udevd/6226: #0: ffff88811c1dad58 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xd8/0x12b0 fs/seq_file.c:182 #1: ffff88811b946488 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_seq_start+0x4d/0x240 fs/kernfs/file.c:154 #2: ffff88811e4c6e18 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x71/0x240 fs/kernfs/file.c:155 #3: ffff888106ef0190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:1014 [inline] #3: ffff888106ef0190 (&dev->mutex){....}-{3:3}, at: uevent_show+0x188/0x3b0 drivers/base/core.c:2736 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-rc6-syzkaller-00153-g237d4e0f4113 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 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:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline] watchdog+0xf0c/0x1240 kernel/hung_task.c:379 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 2861 Comm: udevd Not tainted 6.12.0-rc6-syzkaller-00153-g237d4e0f4113 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 RIP: 0033:0x7fa07d2c5199 Code: e6 0e 00 eb 8f 48 39 f8 75 09 48 8d 3d f2 e6 0e 00 eb 81 49 89 c5 49 ff c0 49 c1 ed 0c 4c 33 28 4c 89 e8 eb c0 44 0f b7 04 4e <4c> 89 c0 4d 39 d8 73 2a 48 89 fa ff c0 4c 89 4d 18 48 c1 ea 0c 48 RSP: 002b:00007ffdf0dff500 EFLAGS: 00000213 RAX: fffffffffffffe98 RBX: 0000000000000210 RCX: 000000000000001f RDX: 0000000000000211 RSI: 000055b5e9f51010 RDI: 000055b5e9f8d4c0 RBP: 000055b5e9f8d4b0 R08: 0000000000000000 R09: ed5da4edc4cc5f73 R10: 102a4a340cd9582b R11: 0000000000000007 R12: 0000000000000000 R13: 0000000200000001 R14: 00007fa07d3efaa0 R15: 0000000000000000 FS: 00007fa07d1e9c80 GS: 0000000000000000