INFO: task syz.0.301:7212 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x1709/0x5530 kernel/sched/core.c:7231 __schedule_loop kernel/sched/core.c:7308 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7323 cgroup_lock_and_drain_offline+0x51a/0x650 kernel/cgroup/cgroup.c:3275 cgroup_kn_lock_live+0x120/0x230 kernel/cgroup/cgroup.c:1715 cgroup_subtree_control_write+0x4b5/0x1080 kernel/cgroup/cgroup.c:3577 cgroup_file_write+0x331/0x8f0 kernel/cgroup/cgroup.c:4316 kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x61e/0xbb0 fs/read_write.c:687 ksys_write+0x156/0x270 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x17b/0x530 arch/x86/entry/syscall_64.c:85 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9b424dde99 RSP: 002b:00007f9b40715028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f9b42766090 RCX: 00007f9b424dde99 RDX: 0000000000000005 RSI: 0000200000000040 RDI: 0000000000000006 RBP: 00007f9b42573eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9b42766128 R14: 00007f9b42766090 R15: 00007ffcc0f78918 Showing all locks held in the system: locks held by kworker/0:0/9: 6, on CPU#0: #0: ffff88801b34a538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffff88801b34a538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffff88801b34a538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344 #1: ffffc900000e7c60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #1: ffffc900000e7c60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #1: ffffc900000e7c60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344 #2: ffff88802ab16210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #2: ffff88802ab16210 (&dev->mutex){....}-{4:4}, at: hub_event+0x187/0x4cf0 drivers/usb/core/hub.c:5899 #3: ffff88802ab23658 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline] #3: ffff88802ab23658 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline] #3: ffff88802ab23658 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #3: ffff88802ab23658 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #3: ffff88802ab23658 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x20ad/0x4cf0 drivers/usb/core/hub.c:5953 #4: ffff88802aa81c58 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5465 [inline] #4: ffff88802aa81c58 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #4: ffff88802aa81c58 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #4: ffff88802aa81c58 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x20e1/0x4cf0 drivers/usb/core/hub.c:5953 #5: ffffffff8f06a920 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x14d/0x1800 drivers/usb/core/hub.c:3067 locks held by pr/legacy/17: 4, last CPU#0: #0: ffffffff8e3b5a40 (console_lock){+.+.}-{0:0}, at: legacy_kthread_func+0x1a3/0x250 kernel/printk/printk.c:3718 #1: ffffffff8e29d338 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:305 [inline] #1: ffffffff8e29d338 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:428 [inline] #1: ffffffff8e29d338 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:291 [inline] #1: ffffffff8e29d338 (console_srcu){....}-{0:0}, at: console_flush_one_record+0xfa/0xb90 kernel/printk/printk.c:3246 #2: ffffffff9a078558 (&port_lock_key){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline] #2: ffffffff9a078558 (&port_lock_key){+.+.}-{3:3}, at: uart_port_lock_irqsave include/linux/serial_core.h:719 [inline] #2: ffffffff9a078558 (&port_lock_key){+.+.}-{3:3}, at: serial8250_console_write+0x17c/0x1b40 drivers/tty/serial/8250/8250_port.c:3344 #3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline] #3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57 locks held by khungtaskd/38: 1, last CPU#1: #0: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6835 locks held by kworker/1:1/43: 4, on CPU#1: #0: ffff88801b34a538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffff88801b34a538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffff88801b34a538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344 #1: ffffc90000b47c60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #1: ffffc90000b47c60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #1: ffffc90000b47c60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344 #2: ffff88802ab3e210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #2: ffff88802ab3e210 (&dev->mutex){....}-{4:4}, at: hub_event+0x187/0x4cf0 drivers/usb/core/hub.c:5899 #3: ffff88802ab24658 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline] #3: ffff88802ab24658 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x61b/0x4cf0 drivers/usb/core/hub.c:5952 locks held by kworker/u8:9/1164: 2, on CPU#0: #0: ffff88801aea4138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffff88801aea4138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffff88801aea4138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344 #1: ffffc90006717c60 (connector_reaper_work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #1: ffffc90006717c60 (connector_reaper_work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #1: ffffc90006717c60 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344 locks held by getty/5350: 2, on CPU#0: #0: ffff888036b5e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc900044ce2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211 locks held by udevd/5590: 4, on CPU#0: #0: ffff888025f2fdb0 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xa5/0xcb0 fs/seq_file.c:183 #1: ffff88803f5e9478 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_seq_start+0x5d/0x420 fs/kernfs/file.c:165 #2: ffff88805ddd2a58 (kn->active#18){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #2: ffff88805ddd2a58 (kn->active#18){.+.+}-{0:0}, at: kernfs_seq_start+0xb2/0x420 fs/kernfs/file.c:166 #3: ffff8880357bc210 (&dev->mutex){....}-{4:4}, at: device_lock_interruptible include/linux/device.h:1109 [inline] #3: ffff8880357bc210 (&dev->mutex){....}-{4:4}, at: manufacturer_show+0x26/0xa0 drivers/usb/core/sysfs.c:142 locks held by kworker/0:6/5755: 6, last CPU#0: #0: ffff88813fe63938 ((wq_completion)events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffff88813fe63938 ((wq_completion)events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffff88813fe63938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344 #1: ffffc90005957c60 ((work_completion)(&intf->reset_ws)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #1: ffffc90005957c60 ((work_completion)(&intf->reset_ws)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #1: ffffc90005957c60 ((work_completion)(&intf->reset_ws)){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344 #2: ffff88803e8d0210 (&dev->mutex){....}-{4:4}, at: device_trylock include/linux/device.h:1114 [inline] #2: ffff88803e8d0210 (&dev->mutex){....}-{4:4}, at: usb_lock_device_for_reset+0x122/0x320 drivers/usb/core/usb.c:908 #3: ffff88802ab24658 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline] #3: ffff88802ab24658 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_reset_device+0x551/0xb20 drivers/usb/core/hub.c:6409 #4: ffff88802aa81a58 (hcd->address0_mutex){+.+.}-{4:4}, at: usb_reset_and_verify_device+0x35c/0x1ac0 drivers/usb/core/hub.c:6204 #5: ffffffff8f06a920 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x14d/0x1800 drivers/usb/core/hub.c:3067 locks held by kworker/1:8/5807: 7, last CPU#1: #0: ffff88801b34a538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffff88801b34a538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffff88801b34a538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344 #1: ffffc90005dafc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #1: ffffc90005dafc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #1: ffffc90005dafc60 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344 #2: ffff88802a974210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #2: ffff88802a974210 (&dev->mutex){....}-{4:4}, at: hub_event+0x187/0x4cf0 drivers/usb/core/hub.c:5899 #3: ffff8880357bc210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #3: ffff8880357bc210 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073 #4: ffff88805ea7f1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline] #4: ffff88805ea7f1d8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1073 #5: ffff888020a8a318 (&(&priv->bus_notifier)->rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x54/0x90 kernel/notifier.c:379 #6: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #6: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #6: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline] #6: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57 locks held by syz.0.301/7212: 3, on CPU#0: #0: ffff888026a33928 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259 #1: ffff88803522e510 (sb_writers#9){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2731 [inline] #1: ffff88803522e510 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683 #2: ffff888034dcf078 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336 locks held by kworker/u8:33/7330: 2, on CPU#1: #0: ffff88801aea4138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffff88801aea4138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffff88801aea4138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344 #1: ffffc90004db7c60 ((reaper_work).work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #1: ffffc90004db7c60 ((reaper_work).work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #1: ffffc90004db7c60 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work+0x7fd/0x1480 kernel/workqueue.c:3344 locks held by syz-executor/7375: 9, last CPU#1: #0: ffffffff8e497010 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1541 [inline] #0: ffffffff8e497010 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x10f/0x480 kernel/fork.c:1594 #1: ffff88803a8c62b0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline] #1: ffff88803a8c62b0 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x16e/0x1d30 mm/mmap.c:1701 #2: ffff88802a05e2b0 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:552 [inline] #2: ffff88802a05e2b0 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x256/0x1d30 mm/mmap.c:1708 #3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290 #4: ffff888025807358 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline] #4: ffff888025807358 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:404 #5: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #5: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #5: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline] #5: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57 #6: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #6: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #6: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290 #7: ffff88803ac33058 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pte_range mm/memory.c:1348 [inline] #7: ffff88803ac33058 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pmd_range+0x541/0x57f0 mm/memory.c:1484 #8: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #8: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #8: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline] #8: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock_nested+0x1de/0x3f0 kernel/locking/spinlock_rt.c:65 locks held by syz.2.798/9066: 1, on CPU#1: #0: ffff88801ae93a30 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline] #0: ffff88801ae93a30 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1e0/0x4e0 mm/util.c:579 locks held by syz.2.798/9070: 6, last CPU#0: #0: ffff88801ae93a30 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:600 [inline] #0: ffff88801ae93a30 (&mm->mmap_lock){++++}-{4:4}, at: __mm_populate+0x182/0x390 mm/gup.c:1942 #1: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #1: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #1: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: do_fault_around mm/memory.c:5902 [inline] #1: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: do_read_fault mm/memory.c:5936 [inline] #1: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: do_fault mm/memory.c:6079 [inline] #1: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: do_pte_missing+0x12cd/0x28f0 mm/memory.c:4645 #2: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #2: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #2: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: filemap_map_pages+0x1e0/0x1c50 mm/filemap.c:3915 #3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #3: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290 #4: ffff88801ae98ad8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline] #4: ffff88801ae98ad8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:404 #5: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #5: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #5: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline] #5: ffffffff8e3c3880 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57 ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xfd7/0x1030 kernel/hung_task.c:561 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 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: 17 Comm: pr/legacy Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026 RIP: 0010:delay_tsc+0x65/0xc0 arch/x86/lib/delay.c:90 Code: c7 4d 29 f7 49 39 df 73 53 bf 01 00 00 00 e8 92 37 45 f6 65 8b 05 1b 20 74 07 85 c0 74 1c f3 90 bf 01 00 00 00 e8 db 35 45 f6 f6 80 01 00 39 c5 75 0e 0f 01 f9 66 90 eb bd e8 36 65 e4 f5 eb RSP: 0018:ffffc90000167a28 EFLAGS: 00000246 RAX: 1ffff11003bdee77 RBX: 0000000000000899 RCX: ffffffff99cc2500 RDX: 00000000000000c2 RSI: ffffffff8bcbd060 RDI: ffffffff8b4ec025 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffffff8b4ebfc0 R12: 1ffffffff340f102 R13: 00000000ffffffff R14: 000000c274df2994 R15: 00000000000002db FS: 0000000000000000(0000) GS:ffff8881259f2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc535267000 CR3: 000000003fe34000 CR4: 00000000003526f0 Call Trace: udelay include/asm-generic/delay.h:62 [inline] wait_for_lsr+0x14d/0x300 drivers/tty/serial/8250/8250_port.c:1988 serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3235 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3300 [inline] serial8250_console_write+0x113a/0x1b40 drivers/tty/serial/8250/8250_port.c:3385 console_emit_next_record kernel/printk/printk.c:3163 [inline] console_flush_one_record+0x667/0xb90 kernel/printk/printk.c:3268 legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3719 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245