syzbot
WARNING in usb_ep_enable
Status:
upstream: reported C repro on 2026/08/01 09:05
Reported-by: syzbot+b97587abb3b094010b9b@syzkaller.appspotmail.com
First crash: 4d16h, last: 3d11h
Sample crash report:
------------[ cut here ]------------
usb_ep_enable: ep129 (ep1in-bulk) has maxpacket 0
WARNING: CPU: 0 PID: 14 at drivers/usb/gadget/udc/core.c:125 usb_ep_enable+0x27c/0x4d0 drivers/usb/gadget/udc/core.c:124
Modules linked in:
CPU: 0 PID: 14 Comm: kworker/0:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: usb_hub_wq hub_event
RIP: 0010:usb_ep_enable+0x27c/0x4d0 drivers/usb/gadget/udc/core.c:124
Code: 49 8b 0e 48 c7 c0 80 cf 3e 8b 49 c7 c0 a0 cf 3e 8b 4c 0f 44 c0 48 c7 c7 40 cf 3e 8b 48 c7 c6 19 aa 63 8c 89 ea e8 d4 f4 ce fa <0f> 0b e9 c4 fe ff ff e8 78 6a 03 fb 49 bc 00 00 00 00 00 fc ff df
RSP: 0018:ffffc90000007788 EFLAGS: 00010046
RAX: 8770641b6d04a100 RBX: ffff8881463d00e0 RCX: ffff88813fea1e00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000002
RBP: 0000000000000081 R08: ffff8880b8e279db R09: 1ffff110171c4f3b
R10: dffffc0000000000 R11: ffffed10171c4f3c R12: dffffc0000000000
R13: ffff8881463d010d R14: ffff8881463d00e8 R15: ffff88802ec5efba
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000033f6242bc000 CR3: 00000000799d6000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
hidg_set_alt+0x126/0xa00 drivers/usb/gadget/function/f_hid.c:822
set_config+0x6e8/0xf70 drivers/usb/gadget/composite.c:986
composite_setup+0x194c/0x2b00 drivers/usb/gadget/composite.c:1893
configfs_composite_setup+0xc3/0x100 drivers/usb/gadget/configfs.c:1484
dummy_timer+0x12ea/0x3420 drivers/usb/gadget/udc/dummy_hcd.c:1936
__run_hrtimer kernel/time/hrtimer.c:1751 [inline]
__hrtimer_run_queues+0x522/0xc90 kernel/time/hrtimer.c:1815
hrtimer_run_softirq+0x173/0x290 kernel/time/hrtimer.c:1832
handle_softirqs+0x291/0x910 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 3f 89 1e f7 65 8b 05 b0 3a c8 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc90000137080 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a02 RCX: 8770641b6d04a100
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: 0000000000000001
RBP: ffffc90000137100 R08: ffffffff90b102af R09: 1ffffffff2162055
R10: dffffc0000000000 R11: fffffbfff2162056 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff8881463d0000 R15: 1ffff92000026e10
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
dummy_urb_enqueue+0x583/0x770 drivers/usb/gadget/udc/dummy_hcd.c:1319
usb_hcd_submit_urb+0x314/0x1970 drivers/usb/core/hcd.c:1558
usb_start_wait_urb+0x13c/0x580 drivers/usb/core/message.c:61
usb_internal_control_msg drivers/usb/core/message.c:116 [inline]
usb_control_msg+0x231/0x3e0 drivers/usb/core/message.c:166
usb_control_msg_send drivers/usb/core/message.c:225 [inline]
usb_set_configuration+0x11a7/0x2030 drivers/usb/core/message.c:2164
usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x24a/0xb40 drivers/base/dd.c:638
__driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
__device_attach_driver+0x2c6/0x510 drivers/base/dd.c:962
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:1034
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3712
usb_new_device+0xa01/0x15e0 drivers/usb/core/hub.c:2659
hub_port_connect drivers/usb/core/hub.c:5517 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5657 [inline]
port_event drivers/usb/core/hub.c:5817 [inline]
hub_event+0x2b2f/0x5200 drivers/usb/core/hub.c:5899
process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
----------------
Code disassembly (best guess):
0: c7 44 24 20 00 00 00 movl $0x0,0x20(%rsp)
7: 00
8: 9c pushf
9: 8f 44 24 20 pop 0x20(%rsp)
d: f7 44 24 20 00 02 00 testl $0x200,0x20(%rsp)
14: 00
15: 41 c6 04 07 f8 movb $0xf8,(%r15,%rax,1)
1a: 75 4b jne 0x67
1c: f7 c3 00 02 00 00 test $0x200,%ebx
22: 74 01 je 0x25
24: fb sti
25: bf 01 00 00 00 mov $0x1,%edi
* 2a: e8 3f 89 1e f7 call 0xf71e896e <-- trapping instruction
2f: 65 8b 05 b0 3a c8 75 mov %gs:0x75c83ab0(%rip),%eax # 0x75c83ae6
36: 85 c0 test %eax,%eax
38: 74 3c je 0x76
3a: 48 rex.W
3b: c7 .byte 0xc7
3c: 04 24 add $0x24,%al
3e: 0e (bad)
3f: 36 ss
* Struck through repros no longer work on HEAD.