INFO: task hung in mmc_stop_host

Status: upstream: reported on 2026/08/25 00:03
Subsystems: mmc
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+d0688023306aea3aefdc@syzkaller.appspotmail.com
First crash: 73d, last: 3h53m
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
ac8ad14a assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ✅ ❓ INFO: task hung in mmc_stop_host 2026/08/09 09:07 2026/08/09 09:07 2026/08/09 09:11 5d63f80b
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[syzbot] Monthly mmc report (Oct 2026) 0 (1) 2026/10/04 04:33
[syzbot] [kernel?] INFO: task hung in mmc_stop_host 0 (1) 2026/08/25 00:03
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in mmc_stop_host 1 2 42d 47d 0/3 upstream: reported on 2026/08/30 19:05
linux-6.6 INFO: task hung in mmc_stop_host 1 5 1d23h 63d 0/2 upstream: reported on 2026/08/14 22:00
linux-5.15 INFO: task hung in mmc_stop_host 1 2 21d 42d 0/3 upstream: reported on 2026/09/05 04:28

Sample crash report:
INFO: task kworker/1:4:5728 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:4     state:D stack:19584 pid:5728  tgid:5728  ppid:2      task_flags:0x4288160 flags:0x00080000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x16d9/0x5700 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7376
 schedule_timeout+0xc0/0x2c0 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common kernel/sched/completion.c:121 [inline]
 wait_for_common kernel/sched/completion.c:132 [inline]
 wait_for_completion+0x2ca/0x5e0 kernel/sched/completion.c:153
 __flush_work+0x9c2/0xd70 kernel/workqueue.c:4448
 __cancel_work_sync+0xbf/0x110 kernel/workqueue.c:4568
 __mmc_stop_host drivers/mmc/core/core.c:2368 [inline]
 mmc_stop_host+0xd9/0x460 drivers/mmc/core/core.c:2373
 mmc_remove_host+0x15/0x60 drivers/mmc/core/host.c:681
 vub300_disconnect+0x154/0x2f0 drivers/mmc/host/vub300.c:2387
 usb_unbind_interface+0x295/0x9f0 drivers/usb/core/driver.c:461
 device_remove drivers/base/dd.c:618 [inline]
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x4f5/0x880 drivers/base/dd.c:1372
 bus_remove_device+0x449/0x560 drivers/base/bus.c:664
 device_del+0x528/0x8f0 drivers/base/core.c:3965
 usb_disable_device+0x3d4/0x8d0 drivers/usb/core/message.c:1484
 usb_disconnect+0x32d/0x990 drivers/usb/core/hub.c:2355
 hub_port_connect drivers/usb/core/hub.c:5425 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5725 [inline]
 port_event drivers/usb/core/hub.c:5889 [inline]
 hub_event+0x1bb7/0x4cf0 drivers/usb/core/hub.c:5971
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/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
 </TASK>
INFO: task kworker/1:5:5744 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:5     state:D stack:20576 pid:5744  tgid:5744  ppid:2      task_flags:0x4208160 flags:0x00080000
Workqueue: events_freezable mmc_rescan
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5533 [inline]
 __schedule+0x16d9/0x5700 kernel/sched/core.c:7284
 __schedule_loop kernel/sched/core.c:7361 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7376
 schedule_timeout+0xc0/0x2c0 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:100 [inline]
 __wait_for_common kernel/sched/completion.c:121 [inline]
 wait_for_common kernel/sched/completion.c:132 [inline]
 wait_for_completion+0x2ca/0x5e0 kernel/sched/completion.c:153
 mmc_wait_for_req_done+0x37/0x490 drivers/mmc/core/core.c:408
 mmc_wait_for_cmd+0x183/0x2a0 drivers/mmc/core/core.c:645
 mmc_io_rw_direct_host drivers/mmc/core/sdio_ops.c:83 [inline]
 sdio_reset+0xf4/0x3a0 drivers/mmc/core/sdio_ops.c:209
 mmc_rescan_try_freq drivers/mmc/core/core.c:2121 [inline]
 mmc_rescan+0x6ee/0x1040 drivers/mmc/core/core.c:2316
 process_one_work kernel/workqueue.c:3396 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
 kthread+0x38b/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
 </TASK>

Showing all locks held in the system:
locks held by khungtaskd/39: 1, last CPU#1:
 #0: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by kworker/1:4/5728: 5, on CPU#1:
 #0: ffff8880212fdd38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff8880212fdd38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff8880212fdd38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff8880212fdd38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc90005977c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90005977c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90005977c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc90005977c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffff88802b856210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #2: ffff88802b856210 (&dev->mutex){....}-{4:4}, at: hub_event+0x187/0x4cf0 drivers/usb/core/hub.c:5917
 #3: ffff88802da5a210 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #3: ffff88802da5a210 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0xe3/0x990 drivers/usb/core/hub.c:2346
 #4: ffff88803be0b1d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #4: ffff88803be0b1d8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
 #4: ffff88803be0b1d8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb9/0x880 drivers/base/dd.c:1369
locks held by kworker/1:5/5744: 2, on CPU#1:
 #0: ffff88813ff2a938 ((wq_completion)events_freezable){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88813ff2a938 ((wq_completion)events_freezable){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88813ff2a938 ((wq_completion)events_freezable){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff88813ff2a938 ((wq_completion)events_freezable){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc90005eb7c40 ((work_completion)(&(&host->detect)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90005eb7c40 ((work_completion)(&(&host->detect)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90005eb7c40 ((work_completion)(&(&host->detect)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc90005eb7c40 ((work_completion)(&(&host->detect)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
locks held by getty/10302: 2, on CPU#0:
 #0: ffff8880343000a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900044db2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
locks held by syz-executor/20140: 9, last CPU#1:
 #0: ffffffff8f29f470 (dup_mmap_sem){++++}-{0:0}, at: dup_mm kernel/fork.c:1542 [inline]
 #0: ffffffff8f29f470 (dup_mmap_sem){++++}-{0:0}, at: copy_mm+0x10a/0x480 kernel/fork.c:1595
 #1: ffff8880419290b8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:562 [inline]
 #1: ffff8880419290b8 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x18e/0x1d80 mm/mmap.c:1716
 #2: ffff88806d94c4b8 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:552 [inline]
 #2: ffff88806d94c4b8 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x27d/0x1d80 mm/mmap.c:1723
 #3: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #3: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #3: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290
 #4: ffff888055cb37d8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #4: ffff888055cb37d8 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:404
 #5: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #5: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #5: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #5: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e2/0x400 kernel/locking/spinlock_rt.c:57
 #6: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #6: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #6: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290
 #7: ffff88805caea4d8 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pte_range mm/memory.c:1354 [inline]
 #7: ffff88805caea4d8 (ptlock_ptr(ptdesc)#2/1){+.+.}-{3:3}, at: copy_pmd_range+0x569/0x58f0 mm/memory.c:1490
 #8: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #8: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #8: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #8: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock_nested+0x1e0/0x400 kernel/locking/spinlock_rt.c:65
locks held by kworker/0:4/24618: 7, last CPU#0:
 #0: ffff88813ff2b938 ((wq_completion)events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff88813ff2b938 ((wq_completion)events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff88813ff2b938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff88813ff2b938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc90004ddfc40 (free_ipc_work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc90004ddfc40 (free_ipc_work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc90004ddfc40 (free_ipc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc90004ddfc40 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffff888040d520e0 (&type->s_umount_key#59){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline]
 #2: ffff888040d520e0 (&type->s_umount_key#59){++++}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
 #2: ffff888040d520e0 (&type->s_umount_key#59){++++}-{4:4}, at: deactivate_super+0xac/0xe0 fs/super.c:613
 #3: ffff888064623088 (&lockref->lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #3: ffff888064623088 (&lockref->lock){+.+.}-{3:3}, at: dentry_kill+0x27f/0x880 fs/dcache.c:837
 #4: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #4: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #4: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #4: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e2/0x400 kernel/locking/spinlock_rt.c:57
 #5: ffffffff8f9d5000 (fill_pool_map-wait-type-override){+.+.}-{3:3}, at: debug_objects_fill_pool+0x3b/0x80 lib/debugobjects.c:779
 #6: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #6: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #6: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: __rt_spin_trylock kernel/locking/spinlock_rt.c:127 [inline]
 #6: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rt_spin_trylock+0x10c/0x2b0 kernel/locking/spinlock_rt.c:135
locks held by syz-executor/24787: 1, on CPU#0:
 #0: ffff8880539fcf80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close net/bluetooth/hci_core.c:500 [inline]
 #0: ffff8880539fcf80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_unregister_dev+0x232/0x5c0 net/bluetooth/hci_core.c:2694
locks held by kworker/u8:65/26010: 5, last CPU#0:
 #0: ffff888034366938 ((wq_completion)bat_events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #0: ffff888034366938 ((wq_completion)bat_events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffff888034366938 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #0: ffff888034366938 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #1: ffffc9000e2a7c40 ((work_completion)(&(&bat_priv->tt.work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffc9000e2a7c40 ((work_completion)(&(&bat_priv->tt.work)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffc9000e2a7c40 ((work_completion)(&(&bat_priv->tt.work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
 #1: ffffc9000e2a7c40 ((work_completion)(&(&bat_priv->tt.work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
 #2: ffffffff8f059580 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3d/0x420 kernel/softirq.c:186
 #3: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3d/0x420 kernel/softirq.c:186
 #4: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #4: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #4: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #4: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e2/0x400 kernel/locking/spinlock_rt.c:57
locks held by syz.5.7065/26702: 4, last CPU#1:
 #0: ffff8880519290b8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:600 [inline]
 #0: ffff8880519290b8 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0 mm/mmap.c:1299
 #1: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290
 #2: ffff8880427b9a18 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #2: ffff8880427b9a18 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:404
 #3: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #3: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #3: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #3: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e2/0x400 kernel/locking/spinlock_rt.c:57
locks held by syz.7.7073/26705: 1, last CPU#0:
 #0: ffff8880416a3158 (sk_lock-AF_INET6){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1713 [inline]
 #0: ffff8880416a3158 (sk_lock-AF_INET6){+.+.}-{0:0}, at: sctp_setsockopt+0x21c/0x12c0 net/sctp/socket.c:4618
locks held by syz.3.7074/26707: 5, last CPU#0:
 #0: ffff888038e09db8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:600 [inline]
 #0: ffff888038e09db8 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x1a4/0x9f0 mm/mmap.c:1299
 #1: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #1: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #1: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x200 mm/pgtable-generic.c:290
 #2: ffff88806e259c58 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #2: ffff88806e259c58 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: pte_offset_map_lock+0x13d/0x210 mm/pgtable-generic.c:404
 #3: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #3: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #3: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #3: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e2/0x400 kernel/locking/spinlock_rt.c:57
 #4: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
 #4: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #4: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 #4: ffffffff8f1c3d00 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e2/0x400 kernel/locking/spinlock_rt.c:57

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 39 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
 nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
 trigger_all_cpu_backtrace include/linux/nmi.h:164 [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+0x38b/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
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 17 Comm: pr/ttyS0 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:409
Code: e8 ae 89 63 fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 af 4e d0 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc900001678b8 EFLAGS: 00000202
RAX: 1ffffffff35d6300 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff85634f60 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff9aeb1f80 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124abb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3421aff8 CR3: 000000006e5f2000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 serial_in drivers/tty/serial/8250/8250.h:128 [inline]
 serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
 wait_for_lsr+0x190/0x300 drivers/tty/serial/8250/8250_port.c:2013
 serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3270 [inline]
 __serial8250_console_fifo_write+0xd0/0x3f0 drivers/tty/serial/8250/8250_port.c:3345
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3378 [inline]
 __serial8250_console_write drivers/tty/serial/8250/8250_port.c:3432 [inline]
 serial8250_console_write+0xaa2/0x1220 drivers/tty/serial/8250/8250_port.c:3496
 nbcon_emit_next_record+0xef5/0x1a90 kernel/printk/nbcon.c:-1
 nbcon_emit_one kernel/printk/nbcon.c:1157 [inline]
 nbcon_kthread_func+0x679/0x880 kernel/printk/nbcon.c:1271
 kthread+0x38b/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
 </TASK>

Crashes (1031):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/16 11:28 upstream 2f2f7eeef8b0 b1757810 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in mmc_stop_host
2026/10/16 05:14 upstream 2f2f7eeef8b0 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in mmc_stop_host
2026/10/15 19:04 upstream 0fcb05b72344 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: task hung in mmc_stop_host
2026/10/15 15:11 upstream 0fcb05b72344 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in mmc_stop_host
2026/10/15 04:18 upstream 4056b3c9d3c9 8fb0ae89 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: task hung in mmc_stop_host
2026/10/14 14:19 upstream ca3e345926b0 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in mmc_stop_host
2026/10/12 04:46 upstream b88c841d1164 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in mmc_stop_host
2026/08/23 19:26 upstream 388b607d107c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in mmc_stop_host
2026/08/20 23:38 upstream 9328b3b03bdc 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in mmc_stop_host
2026/08/18 08:16 upstream ff68e5f557f6 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in mmc_stop_host
2026/10/13 01:18 upstream 24a19b953e2a 745a967f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: task hung in mmc_stop_host
2026/10/17 04:06 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 893584e7e390 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/17 02:40 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 893584e7e390 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/17 01:27 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 893584e7e390 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/16 23:14 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 893584e7e390 4c840a2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/16 20:24 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 893584e7e390 4c840a2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/16 17:57 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 893584e7e390 4c840a2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/16 15:44 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 04ac7b445880 4c840a2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/16 13:07 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 04ac7b445880 4c840a2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/16 12:31 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 04ac7b445880 4c840a2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/16 08:24 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 04ac7b445880 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/16 06:25 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 04ac7b445880 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/16 02:06 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 04ac7b445880 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/16 00:04 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 04ac7b445880 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/15 21:04 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 04ac7b445880 3f2522c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/15 17:11 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 04ac7b445880 8fb0ae89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/15 14:00 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 8fb0ae89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/15 07:17 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 8fb0ae89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/15 02:27 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 8fb0ae89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/15 01:14 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 8fb0ae89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/14 21:00 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 1a71827b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/14 13:05 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 1a71827b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/14 12:01 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 1a71827b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/14 09:37 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/14 08:28 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/14 05:42 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/13 19:41 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 5a1eeac4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/13 18:36 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 5a1eeac4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/13 15:14 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 5a1eeac4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/13 13:48 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 5a1eeac4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/13 06:11 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 745a967f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/12 19:58 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 745a967f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/12 18:34 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 745a967f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/12 17:01 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 745a967f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/12 14:17 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 745a967f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/12 08:23 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/12 06:29 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/12 01:23 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/11 21:12 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing bbf6b99a57b2 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/11 17:49 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 8f0d16174102 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/11 16:06 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 8f0d16174102 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/11 14:47 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 8f0d16174102 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/11 13:36 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 8f0d16174102 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/11 04:45 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 648b08aa37c1 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/11 03:27 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 648b08aa37c1 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/11 01:58 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 648b08aa37c1 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/10/10 22:57 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 648b08aa37c1 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: task hung in mmc_stop_host
2026/09/24 09:31 linux-next 9d80aa4617b3 3c3cdf19 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in mmc_stop_host
2026/09/07 22:14 linux-next 9d80aa4617b3 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: task hung in mmc_stop_host
2026/08/04 17:48 linux-next cc2b5f627e8c d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: task hung in mmc_stop_host
2026/10/01 05:41 https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux master 551c722f4080 38f7f0d1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm32 INFO: task hung in mmc_stop_host
* Struck through repros no longer work on HEAD.