syzbot
WARNING in usb_ep_enable
Status:
upstream: reported C repro on 2026/07/31 21:09
Reported-by: syzbot+d851455dbf571fe8e225@syzkaller.appspotmail.com
First crash: 5d08h, last: 1d10h
Sample crash report:
------------[ cut here ]------------
usb_ep_enable: ep129 (ep1in-bulk) has maxpacket 0
WARNING: CPU: 0 PID: 5154 at drivers/usb/gadget/udc/core.c:125 usb_ep_enable+0x263/0x440 drivers/usb/gadget/udc/core.c:124
Modules linked in:
CPU: 0 PID: 5154 Comm: kworker/0:3 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+0x263/0x440 drivers/usb/gadget/udc/core.c:124
Code: 49 8b 0e 48 c7 c0 40 bd 7a 8b 49 c7 c0 60 bd 7a 8b 4c 0f 44 c0 48 c7 c7 00 bd 7a 8b 48 c7 c6 e7 8b a6 8c 89 ea e8 fd e0 97 fa <0f> 0b e9 e1 fe ff ff e8 e1 10 ce fa 49 bc 00 00 00 00 00 fc ff df
RSP: 0018:ffffc900000077b0 EFLAGS: 00010046
RAX: feee2053634aca00 RBX: ffff8881437480e0 RCX: ffff88807de61e00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000002
RBP: 0000000000000081 R08: ffff8880b8e28c53 R09: 1ffff110171c518a
R10: dffffc0000000000 R11: ffffed10171c518b R12: dffffc0000000000
R13: ffff88814374810d R14: ffff8881437480e8 R15: ffff88802ddc46ba
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f43be1ef2f8 CR3: 000000002dd59000 CR4: 00000000003506f0
Call Trace:
<IRQ>
hidg_set_alt+0x12a/0xa10 drivers/usb/gadget/function/f_hid.c:826
set_config+0x735/0xff0 drivers/usb/gadget/composite.c:1018
composite_setup+0x1df4/0x33a0 drivers/usb/gadget/composite.c:1925
configfs_composite_setup+0xc7/0x100 drivers/usb/gadget/configfs.c:1875
dummy_timer+0x1309/0x3420 drivers/usb/gadget/udc/dummy_hcd.c:1935
__run_hrtimer kernel/time/hrtimer.c:1754 [inline]
__hrtimer_run_queues+0x525/0xc10 kernel/time/hrtimer.c:1818
hrtimer_run_softirq+0x177/0x290 kernel/time/hrtimer.c:1835
handle_softirqs+0x27d/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xc0/0x120 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> 3b 6f c6 f6 65 8b 05 9c 3d 6d 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc900033b6fe0 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a06 RCX: feee2053634aca00
RDX: dffffc0000000000 RSI: ffffffff8acacbe0 RDI: 0000000000000001
RBP: ffffc900033b7070 R08: ffffffff911eb56f R09: 1ffffffff223d6ad
R10: dffffc0000000000 R11: fffffbfff223d6ae R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff888143748000 R15: 1ffff92000676dfc
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
dummy_urb_enqueue+0x587/0x780 drivers/usb/gadget/udc/dummy_hcd.c:1318
usb_hcd_submit_urb+0x318/0x1aa0 drivers/usb/core/hcd.c:1533
usb_start_wait_urb+0x140/0x580 drivers/usb/core/message.c:62
usb_internal_control_msg drivers/usb/core/message.c:117 [inline]
usb_control_msg+0x235/0x3e0 drivers/usb/core/message.c:167
usb_control_msg_send drivers/usb/core/message.c:226 [inline]
usb_set_configuration+0x12a8/0x2150 drivers/usb/core/message.c:2206
usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:238
usb_probe_device+0x12a/0x260 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x247/0xae0 drivers/base/dd.c:717
__driver_probe_device+0x1f5/0x390 drivers/base/dd.c:879
driver_probe_device+0x4f/0x420 drivers/base/dd.c:909
__device_attach_driver+0x2ca/0x510 drivers/base/dd.c:1037
bus_for_each_drv+0x252/0x2e0 drivers/base/bus.c:459
__device_attach+0x2c1/0x420 drivers/base/dd.c:1109
bus_probe_device+0x180/0x260 drivers/base/bus.c:580
device_add+0x87c/0xc40 drivers/base/core.c:3700
usb_new_device+0x995/0x1550 drivers/usb/core/hub.c:2660
hub_port_connect drivers/usb/core/hub.c:5529 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5669 [inline]
port_event drivers/usb/core/hub.c:5833 [inline]
hub_event+0x29d5/0x4a80 drivers/usb/core/hub.c:5915
process_one_work kernel/workqueue.c:2653 [inline]
process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2730
worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2811
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</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 3b 6f c6 f6 call 0xf6c66f6a <-- trapping instruction
2f: 65 8b 05 9c 3d 6d 75 mov %gs:0x756d3d9c(%rip),%eax # 0x756d3dd2
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.