[syzbot] [usb?] general protection fault in qt2_read_bulk_callback (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 615aad0f61e0 Add linux-next specific files for 20260126
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1761a05a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d51c584a7396ddf1
dashboard link: https://syzkaller.appspot.com/bug?extid=c63f59479d561970dc2b
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=145d6bfa580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14dac98a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5318e5f027be/disk-615aad0f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d165e561fa49/vmlinux-615aad0f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fb0e01c90aa5/bzImage-615aad0f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c63f59...@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000038: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x00000000000001c0-0x00000000000001c7]
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
Workqueue: usb_hub_wq hub_event
RIP: 0010:__queue_work+0xa2/0xf90 kernel/workqueue.c:2269
Code: 11 31 ff 89 ee e8 4e f4 37 00 85 ed 0f 85 ef 0c 00 00 e8 01 f0 37 00 4d 8d b7 c0 01 00 00 4c 89 f0 48 c1 e8 03 48 89 44 24 28 <42> 0f b6 04 20 84 c0 0f 85 22 0d 00 00 4c 89 34 24 41 8b 2e 89 ee
RSP: 0018:ffffc900000077f8 EFLAGS: 00010002
RAX: 0000000000000038 RBX: 0000000000000008 RCX: ffff88801dafdac0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88803642c01f R09: 1ffff11006c85803
R10: dffffc0000000000 R11: ffffed1006c85804 R12: dffffc0000000000
R13: ffff88803642c018 R14: 00000000000001c0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881252b4000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fef907e8600 CR3: 000000000e54a000 CR4: 00000000003526f0
Call Trace:
<IRQ>
queue_work_on+0x106/0x1d0 kernel/workqueue.c:2405
qt2_process_read_urb drivers/usb/serial/quatech2.c:541 [inline]
qt2_read_bulk_callback+0xe96/0x1030 drivers/usb/serial/quatech2.c:574
__usb_hcd_giveback_urb+0x376/0x540 drivers/usb/core/hcd.c:1657
dummy_timer+0xbbd/0x45d0 drivers/usb/gadget/udc/dummy_hcd.c:1995
__run_hrtimer kernel/time/hrtimer.c:1785 [inline]
__hrtimer_run_queues+0x529/0xc30 kernel/time/hrtimer.c:1849
hrtimer_run_softirq+0x182/0x5a0 kernel/time/hrtimer.c:1866
handle_softirqs+0x22a/0x7c0 kernel/softirq.c:626
__do_softirq kernel/softirq.c:660 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x5f/0x150 kernel/softirq.c:727
irq_exit_rcu+0x9/0x30 kernel/softirq.c:743
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x221/0x330 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 e1 1d fe 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 fb bd 75 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 88 6b 72
RSP: 0018:ffffc900000e69a0 EFLAGS: 00000286
RAX: 36c2f4075e728c00 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 0000000000000007 RSI: ffffffff8e14e200 RDI: ffffffff8c273e00
RBP: ffffffff821fd99c R08: ffffc900000e67c0 R09: 0000000000000020
R10: ffffc900000e6bd0 R11: ffffffff81a16e20 R12: 0000000000000000
R13: ffffffff8e895dc0 R14: 0000000000000001 R15: 0000000000000246
fs_reclaim_acquire+0x98/0x100 mm/page_alloc.c:4359
might_alloc include/linux/sched/mm.h:317 [inline]
slab_pre_alloc_hook mm/slub.c:4403 [inline]
slab_alloc_node mm/slub.c:4758 [inline]
kmem_cache_alloc_noprof+0x40/0x650 mm/slub.c:4788
radix_tree_node_alloc+0x7e/0x3a0 lib/radix-tree.c:276
idr_get_free+0x2b3/0xa70 lib/radix-tree.c:1506
idr_alloc_u32+0x18d/0x320 lib/idr.c:48
idr_alloc+0x6e/0xd0 lib/idr.c:89
allocate_minors+0x98/0x2b0 drivers/usb/serial/usb-serial.c:95
usb_serial_probe+0x25e7/0x2e50 drivers/usb/serial/usb-serial.c:1137
usb_probe_interface+0x668/0xc90 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x267/0xaf0 drivers/base/dd.c:661
__driver_probe_device+0x18c/0x320 drivers/base/dd.c:803
driver_probe_device+0x4f/0x240 drivers/base/dd.c:833
__device_attach_driver+0x2d4/0x4c0 drivers/base/dd.c:961
bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
__device_attach+0x2c5/0x450 drivers/base/dd.c:1033
device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1088
bus_probe_device+0x12a/0x220 drivers/base/bus.c:574
device_add+0x7b6/0xb70 drivers/base/core.c:3689
usb_set_configuration+0x1a87/0x2110 drivers/usb/core/message.c:2210
usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
usb_probe_device+0x1c4/0x3b0 drivers/usb/core/driver.c:291
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x267/0xaf0 drivers/base/dd.c:661
__driver_probe_device+0x18c/0x320 drivers/base/dd.c:803
driver_probe_device+0x4f/0x240 drivers/base/dd.c:833
__device_attach_driver+0x2d4/0x4c0 drivers/base/dd.c:961
bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
__device_attach+0x2c5/0x450 drivers/base/dd.c:1033
device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1088
bus_probe_device+0x12a/0x220 drivers/base/bus.c:574
device_add+0x7b6/0xb70 drivers/base/core.c:3689
usb_new_device+0xa08/0x16f0 drivers/usb/core/hub.c:2695
hub_port_connect drivers/usb/core/hub.c:5567 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
port_event drivers/usb/core/hub.c:5871 [inline]
hub_event+0x2a1c/0x4f30 drivers/usb/core/hub.c:5953
process_one_work+0x949/0x15a0 kernel/workqueue.c:3279
process_scheduled_works kernel/workqueue.c:3362 [inline]
worker_thread+0xb46/0x1140 kernel/workqueue.c:3443
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__queue_work+0xa2/0xf90 kernel/workqueue.c:2269
Code: 11 31 ff 89 ee e8 4e f4 37 00 85 ed 0f 85 ef 0c 00 00 e8 01 f0 37 00 4d 8d b7 c0 01 00 00 4c 89 f0 48 c1 e8 03 48 89 44 24 28 <42> 0f b6 04 20 84 c0 0f 85 22 0d 00 00 4c 89 34 24 41 8b 2e 89 ee
RSP: 0018:ffffc900000077f8 EFLAGS: 00010002
RAX: 0000000000000038 RBX: 0000000000000008 RCX: ffff88801dafdac0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88803642c01f R09: 1ffff11006c85803
R10: dffffc0000000000 R11: ffffed1006c85804 R12: dffffc0000000000
R13: ffff88803642c018 R14: 00000000000001c0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881252b4000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fef907e8600 CR3: 000000000e54a000 CR4: 00000000003526f0
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 31 ff xor %edi,%edi
2: 89 ee mov %ebp,%esi
4: e8 4e f4 37 00 call 0x37f457
9: 85 ed test %ebp,%ebp
b: 0f 85 ef 0c 00 00 jne 0xd00
11: e8 01 f0 37 00 call 0x37f017
16: 4d 8d b7 c0 01 00 00 lea 0x1c0(%r15),%r14
1d: 4c 89 f0 mov %r14,%rax
20: 48 c1 e8 03 shr $0x3,%rax
24: 48 89 44 24 28 mov %rax,0x28(%rsp)
* 29: 42 0f b6 04 20 movzbl (%rax,%r12,1),%eax <-- trapping instruction
2e: 84 c0 test %al,%al
30: 0f 85 22 0d 00 00 jne 0xd58
36: 4c 89 34 24 mov %r14,(%rsp)
3a: 41 8b 2e mov (%r14),%ebp
3d: 89 ee mov %ebp,%esi


---
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