BUG: soft lockup in usbdev_ioctl

Status: moderation: reported on 2026/07/17 09:31
Subsystems: kernfs
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+98bcf7f86f55ce860122@syzkaller.appspotmail.com
First crash: 34d, last: 34d
▶ ▼ ✨ AI Jobs (4)
ID Workflow Result Correct Bug Created Started Finished Revision
a33431f6 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ BUG: soft lockup in usbdev_ioctl 2026/07/24 00:01 2026/07/24 00:01 2026/07/24 00:05 71a13572
68f62be5 assessment-security 💥 BUG: soft lockup in usbdev_ioctl 2026/07/20 00:00 2026/07/20 00:00 2026/07/20 00:23 72524a66
10af1dbd assessment-security 💥 BUG: soft lockup in usbdev_ioctl 2026/07/17 00:01 2026/07/17 00:01 2026/07/17 00:31 49f47391
fc5b9b85 assessment-security 💥 BUG: soft lockup in usbdev_ioctl 2026/07/15 00:03 2026/07/15 00:03 2026/07/15 00:29 2130f682
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in usbdev_ioctl (2) kernel 1 1 1710d 1710d 0/29 closed as invalid on 2022/02/08 10:10
upstream INFO: rcu detected stall in usbdev_ioctl (3) kernel 1 2 601d 614d 0/29 auto-obsoleted due to no activity on 2025/03/23 18:26

Sample crash report:
watchdog: BUG: soft lockup - CPU#0 stuck for 50s! [syz.6.1930:12307]
Modules linked in:
irq event stamp: 113
hardirqs last  enabled at (113): [<ffff8000868e46ac>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:178 [inline]
hardirqs last  enabled at (113): [<ffff8000868e46ac>] _raw_spin_unlock_irqrestore+0x38/0x98 kernel/locking/spinlock.c:198
hardirqs last disabled at (112): [<ffff8000868e44dc>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:130 [inline]
hardirqs last disabled at (112): [<ffff8000868e44dc>] _raw_spin_lock_irqsave+0x2c/0x7c kernel/locking/spinlock.c:166
softirqs last  enabled at (24): [<ffff800080139980>] local_bh_enable include/linux/bottom_half.h:33 [inline]
softirqs last  enabled at (24): [<ffff800080139980>] put_cpu_fpsimd_context arch/arm64/kernel/fpsimd.c:251 [inline]
softirqs last  enabled at (24): [<ffff800080139980>] do_sve_acc+0x32c/0x4b8 arch/arm64/kernel/fpsimd.c:1349
softirqs last disabled at (22): [<ffff800080139760>] local_bh_disable include/linux/bottom_half.h:20 [inline]
softirqs last disabled at (22): [<ffff800080139760>] get_cpu_fpsimd_context arch/arm64/kernel/fpsimd.c:234 [inline]
softirqs last disabled at (22): [<ffff800080139760>] do_sve_acc+0x10c/0x4b8 arch/arm64/kernel/fpsimd.c:1325
CPU: 0 UID: 0 PID: 12307 Comm: syz.6.1930 Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/02/2026
pstate: 63400005 (nZCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : lock_acquire+0x16c/0x364 arch/arm64/include/asm/irqflags.h:-1
lr : lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline]
lr : lock_acquire+0x14c/0x364 kernel/locking/lockdep.c:5870
sp : ffff800097997660
x29: ffff8000979976b0 x28: 0000000000000000 x27: 0000000000000000
x26: ffff800088a712f0 x25: 0000000000000000 x24: 0000000000000001
x23: 0000000000000000 x22: ffff0000c1919210 x21: ffff800080efd3c4
x20: 0000000000000000 x19: 0000000000000000 x18: 00000000ffffffff
x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
x14: 0000000000000000 x13: 0000000000000001 x12: ffff0000e3b3d7c0
x11: 0000000000003d4e x10: 0000000000000003 x9 : 0000000000000000
x8 : 00000000000000c0 x7 : 0000000000000000 x6 : ffff80008048ce60
x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff80008049d250
x2 : 0000000100000000 x1 : ffff0000e3b3d7c0 x0 : 0000000000000000
Call trace:
 __daif_local_irq_restore arch/arm64/include/asm/irqflags.h:175 [inline] (P)
 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:195 [inline] (P)
 lock_acquire+0x16c/0x364 kernel/locking/lockdep.c:5871 (P)
 down_write+0x50/0xc0 kernel/locking/rwsem.c:1631
 __kernfs_remove+0x174/0x718 fs/kernfs/dir.c:1558
 kernfs_remove_by_name_ns+0x70/0xd0 fs/kernfs/dir.c:1797
 kernfs_remove_by_name include/linux/kernfs.h:644 [inline]
 sysfs_remove_link+0x5c/0x6c fs/sysfs/symlink.c:152
 unlink_peers drivers/usb/core/port.c:606 [inline]
 usb_hub_remove_port_device+0x1ac/0x268 drivers/usb/core/port.c:860
 hub_disconnect+0x120/0x358 drivers/usb/core/hub.c:1823
 usb_unbind_interface+0x180/0x6d4 drivers/usb/core/driver.c:458
 device_remove+0x114/0x134 drivers/base/dd.c:618
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x124/0x20c drivers/base/dd.c:1372
 device_release_driver+0x28/0x38 drivers/base/dd.c:1395
 usb_driver_release_interface+0x10c/0x178 drivers/usb/core/driver.c:640
 proc_disconnect_claim+0x2b4/0x330 drivers/usb/core/devio.c:2491
 usbdev_do_ioctl drivers/usb/core/devio.c:2782 [inline]
 usbdev_ioctl+0xe0c/0x1990 drivers/usb/core/devio.c:2826
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736
 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 26 Comm: kworker/1:1 Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/02/2026
Workqueue: events jump_label_update_timeout
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : csd_lock_wait kernel/smp.c:342 [inline]
pc : smp_call_function_many_cond+0xfd0/0x1640 kernel/smp.c:892
lr : csd_lock_wait kernel/smp.c:342 [inline]
lr : smp_call_function_many_cond+0xfe8/0x1640 kernel/smp.c:892
sp : ffff80008ed078e0
x29: ffff80008ed079c0 x28: 0000000000000011 x27: 0000000000000000
x26: ffff0001adead980 x25: ffff800088acb6a0 x24: ffffffffffffffff
x23: 1fffe00035bd5b30 x22: dfff800000000000 x21: 1fffe00035bd5b31
x20: ffff0001adead988 x19: ffff0001ade8ee08 x18: 00000000fe6a6f74
x17: 0000000000000000 x16: 0000000000000001 x15: 0000000000000000
x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000000
x11: 0000000000000000 x10: ffff600035bd1dc2 x9 : 0000000000000000
x8 : 0000000000000011 x7 : 0000000000000000 x6 : ffff80008016a448
x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff8000805b79b8
x2 : 0000000000000000 x1 : ffff0000c1b29d40 x0 : 0000000000000000
Call trace:
 __cmpwait_case_32 arch/arm64/include/asm/cmpxchg.h:233 [inline] (P)
 __cmpwait arch/arm64/include/asm/cmpxchg.h:259 [inline] (P)
 csd_lock_wait kernel/smp.c:342 [inline] (P)
 smp_call_function_many_cond+0xfd0/0x1640 kernel/smp.c:892 (P)
 smp_call_function_many kernel/smp.c:915 [inline]
 smp_call_function+0x58/0xbc kernel/smp.c:935
 kick_all_cpus_sync+0x28/0x34 kernel/smp.c:1081
 arch_jump_label_transform_apply+0x14/0x20 arch/arm64/kernel/jump_label.c:34
 __jump_label_update+0x31c/0x344 kernel/jump_label.c:521
 jump_label_update+0x428/0x4b8 kernel/jump_label.c:910
 __static_key_slow_dec_cpuslocked+0xc4/0x138 kernel/jump_label.c:315
 __static_key_slow_dec kernel/jump_label.c:321 [inline]
 jump_label_update_timeout+0x28/0x3c kernel/jump_label.c:329
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0x788/0x10b8 kernel/workqueue.c:3405
 worker_thread+0x798/0xbd0 kernel/workqueue.c:3486
 kthread+0x304/0x3d4 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:842
IPVS: fo: UDP 224.0.0.2:0 - no destination available
IPVS: fo: UDP 224.0.0.2:0 - no destination available
IPVS: fo: UDP 224.0.0.2:0 - no destination available

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/13 09:19 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci a52d6c7160f7 a870962e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: soft lockup in usbdev_ioctl
* Struck through repros no longer work on HEAD.