Re: [syzbot] [usb?] stack segment fault in __usb_hcd_giveback_urb

[syzbot <syzbot+9a4aec827829942045ff@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
stack segment fault in __usb_hcd_giveback_urb

Oops: stack segment: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 Not tainted 6.15.0-syzkaller-13655-gbdc7f8c5adad #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: usb_hub_wq hub_event
RIP: 0010:__queue_work+0x9e/0xfe0 kernel/workqueue.c:2256
Code: 8b 1d fe 53 12 11 31 ff 89 de e8 5d 97 35 00 85 db 0f 85 fc 0c 00 00 e8 10 93 35 00 49 8d 97 c0 01 00 00 48 89 d5 48 c1 ed 03 <42> 0f b6 44 25 00 84 c0 48 89 54 24 08 0f 85 44 0d 00 00 8b 1a 89
RSP: 0018:ffffc90000007708 EFLAGS: 00010002
RAX: ffffffff818ac910 RBX: 0000000000000000 RCX: ffff88801d2b1e00
RDX: 00000000000001c0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000038 R08: ffff888030913bf7 R09: 1ffff1100612277e
R10: dffffc0000000000 R11: ffffed100612277f R12: dffffc0000000000
R13: ffff888030913bf0 R14: 0000000000000008 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125c52000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c4d8c01950 CR3: 000000006f4f2000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 queue_work_on+0x181/0x270 kernel/workqueue.c:2392
 __usb_hcd_giveback_urb+0x417/0x690 drivers/usb/core/hcd.c:1650
 dummy_timer+0x862/0x4550 drivers/usb/gadget/udc/dummy_hcd.c:1994
 __run_hrtimer kernel/time/hrtimer.c:1761 [inline]
 __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825
 hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1842
 handle_softirqs+0x286/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:console_flush_all+0x7f7/0xc40 kernel/printk/printk.c:3227
Code: 48 21 c3 0f 85 e9 01 00 00 e8 e5 20 1f 00 48 8b 5c 24 20 4d 85 f6 75 07 e8 d6 20 1f 00 eb 06 e8 cf 20 1f 00 fb 48 8b 44 24 28 <42> 80 3c 20 00 74 08 48 89 df e8 ca 97 82 00 48 8b 1b 48 8b 44 24
RSP: 0018:ffffc900000f70a0 EFLAGS: 00000293
RAX: 1ffffffff1d36b07 RBX: ffffffff8e9b5838 RCX: ffff88801d2b1e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900000f71f0 R08: ffffffff8fa112f7 R09: 1ffffffff1f4225e
R10: dffffc0000000000 R11: fffffbfff1f4225f R12: dffffc0000000000
R13: 0000000000000001 R14: 0000000000000200 R15: ffffffff8e9b57e0
 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
 console_unlock+0xc4/0x270 kernel/printk/printk.c:3325
 vprintk_emit+0x5b7/0x7a0 kernel/printk/printk.c:2450
 dev_vprintk_emit+0x337/0x3f0 drivers/base/core.c:4917
 dev_printk_emit+0xe0/0x130 drivers/base/core.c:4928
 _dev_info+0x10a/0x160 drivers/base/core.c:4986
 usb_disconnect+0xdd/0x910 drivers/usb/core/hub.c:2298
 hub_port_connect drivers/usb/core/hub.c:5375 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5675 [inline]
 port_event drivers/usb/core/hub.c:5835 [inline]
 hub_event+0x1cdb/0x4a00 drivers/usb/core/hub.c:5917
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__queue_work+0x9e/0xfe0 kernel/workqueue.c:2256
Code: 8b 1d fe 53 12 11 31 ff 89 de e8 5d 97 35 00 85 db 0f 85 fc 0c 00 00 e8 10 93 35 00 49 8d 97 c0 01 00 00 48 89 d5 48 c1 ed 03 <42> 0f b6 44 25 00 84 c0 48 89 54 24 08 0f 85 44 0d 00 00 8b 1a 89
RSP: 0018:ffffc90000007708 EFLAGS: 00010002
RAX: ffffffff818ac910 RBX: 0000000000000000 RCX: ffff88801d2b1e00
RDX: 00000000000001c0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000038 R08: ffff888030913bf7 R09: 1ffff1100612277e
R10: dffffc0000000000 R11: ffffed100612277f R12: dffffc0000000000
R13: ffff888030913bf0 R14: 0000000000000008 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125c52000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c4d8c01950 CR3: 000000006f4f2000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	8b 1d fe 53 12 11    	mov    0x111253fe(%rip),%ebx        # 0x11125404
   6:	31 ff                	xor    %edi,%edi
   8:	89 de                	mov    %ebx,%esi
   a:	e8 5d 97 35 00       	call   0x35976c
   f:	85 db                	test   %ebx,%ebx
  11:	0f 85 fc 0c 00 00    	jne    0xd13
  17:	e8 10 93 35 00       	call   0x35932c
  1c:	49 8d 97 c0 01 00 00 	lea    0x1c0(%r15),%rdx
  23:	48 89 d5             	mov    %rdx,%rbp
  26:	48 c1 ed 03          	shr    $0x3,%rbp
* 2a:	42 0f b6 44 25 00    	movzbl 0x0(%rbp,%r12,1),%eax <-- trapping instruction
  30:	84 c0                	test   %al,%al
  32:	48 89 54 24 08       	mov    %rdx,0x8(%rsp)
  37:	0f 85 44 0d 00 00    	jne    0xd81
  3d:	8b 1a                	mov    (%rdx),%ebx
  3f:	89                   	.byte 0x89


Tested on:

commit:         bdc7f8c5 Merge tag 'mm-stable-2025-06-06-16-09' of git..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=162f6c0c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fd0cea6d0f67318f
dashboard link: https://syzkaller.appspot.com/bug?extid=9a4aec827829942045ff
compiler:       Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6

Note: no patches were applied.