[syzbot] [sound?] general protection fault in snd_scarlett2_init

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: bb375c251ab4 dt-bindings: usb: st,st-ohci-300x: convert to..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
console output: https://syzkaller.appspot.com/x/log.txt?x=138f1b5a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f1500201919951cc
dashboard link: https://syzkaller.appspot.com/bug?extid=ae893a8901067fde2741
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14ffb006580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12ebbb5a580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2475c3172471/disk-bb375c25.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/30449aa672dd/vmlinux-bb375c25.xz
kernel image: https://storage.googleapis.com/syzbot-assets/46d3937d1c16/bzImage-bb375c25.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ae893a...@syzkaller.appspotmail.com

usb 4-1: 0:6 : does not exist
usb 4-1: 0:7 : does not exist
usb 4-1: 0:8 : does not exist
usb 4-1: 0:9 : does not exist
usb 4-1: 0:10 : does not exist
usb 4-1: Focusrite Scarlett Gen 3 Mixer Driver enabled (pid=0x8215); report any issues to https://github.com/geoffreybennett/scarlett-gen2/issues
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 28 Comm: kworker/1:1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: usb_hub_wq hub_event
RIP: 0010:usb_endpoint_num include/uapi/linux/usb/ch9.h:479 [inline]
RIP: 0010:scarlett2_find_fc_interface sound/usb/mixer_scarlett2.c:8261 [inline]
RIP: 0010:scarlett2_init_private sound/usb/mixer_scarlett2.c:8295 [inline]
RIP: 0010:snd_scarlett2_controls_create sound/usb/mixer_scarlett2.c:8684 [inline]
RIP: 0010:snd_scarlett2_init.cold+0xbad/0x6c79 sound/usb/mixer_scarlett2.c:9407
Code: 84 c0 74 06 0f 8e ca 0b 00 00 48 8b 44 24 20 48 8d 7b 02 48 89 fa 40 88 a8 48 02 00 00 b8 ff ff 37 00 48 c1 ea 03 48 c1 e0 2a <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 9e 0b 00 00
RSP: 0018:ffffc900001e68d8 EFLAGS: 00010286
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff81543c4b
RDX: 0000000000000000 RSI: ffffffff81543c5d RDI: 0000000000000002
RBP: 0000000000000001 R08: 0000000000000001 R09: 00000000000000ff
R10: 00000000000000ff R11: 0000000000000000 R12: ffff88811dd24804
R13: dffffc0000000000 R14: ffff88811dd248a8 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8882687d3000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000558c34efbe88 CR3: 00000000094ae000 CR4: 00000000003506f0
Call Trace:
<TASK>
snd_usb_mixer_apply_create_quirk+0x1c21/0x2b80 sound/usb/mixer_quirks.c:4446
snd_usb_create_mixer+0x7a2/0x1910 sound/usb/mixer.c:3641
usb_audio_probe+0xf6d/0x3a90 sound/usb/card.c:1033
usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:583 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:661
__driver_probe_device+0x1de/0x400 drivers/base/dd.c:803
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:833
__device_attach_driver+0x1ff/0x3e0 drivers/base/dd.c:961
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
__device_attach+0x1e4/0x4d0 drivers/base/dd.c:1033
device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1088
bus_probe_device+0x64/0x160 drivers/base/bus.c:574
device_add+0x11d9/0x1950 drivers/base/core.c:3689
usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2208
usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250
usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:291
call_driver_probe drivers/base/dd.c:583 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:661
__driver_probe_device+0x1de/0x400 drivers/base/dd.c:803
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:833
__device_attach_driver+0x1ff/0x3e0 drivers/base/dd.c:961
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
__device_attach+0x1e4/0x4d0 drivers/base/dd.c:1033
device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1088
bus_probe_device+0x64/0x160 drivers/base/bus.c:574
device_add+0x11d9/0x1950 drivers/base/core.c:3689
usb_new_device.cold+0x685/0x115c 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+0x314d/0x4af0 drivers/usb/core/hub.c:5953
process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275
process_scheduled_works kernel/workqueue.c:3358 [inline]
worker_thread+0x5da/0xe40 kernel/workqueue.c:3439
kthread+0x370/0x450 kernel/kthread.c:467
ret_from_fork+0x6c3/0xcb0 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:usb_endpoint_num include/uapi/linux/usb/ch9.h:479 [inline]
RIP: 0010:scarlett2_find_fc_interface sound/usb/mixer_scarlett2.c:8261 [inline]
RIP: 0010:scarlett2_init_private sound/usb/mixer_scarlett2.c:8295 [inline]
RIP: 0010:snd_scarlett2_controls_create sound/usb/mixer_scarlett2.c:8684 [inline]
RIP: 0010:snd_scarlett2_init.cold+0xbad/0x6c79 sound/usb/mixer_scarlett2.c:9407
Code: 84 c0 74 06 0f 8e ca 0b 00 00 48 8b 44 24 20 48 8d 7b 02 48 89 fa 40 88 a8 48 02 00 00 b8 ff ff 37 00 48 c1 ea 03 48 c1 e0 2a <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 9e 0b 00 00
RSP: 0018:ffffc900001e68d8 EFLAGS: 00010286

RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff81543c4b
RDX: 0000000000000000 RSI: ffffffff81543c5d RDI: 0000000000000002
RBP: 0000000000000001 R08: 0000000000000001 R09: 00000000000000ff
R10: 00000000000000ff R11: 0000000000000000 R12: ffff88811dd24804
R13: dffffc0000000000 R14: ffff88811dd248a8 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8882687d3000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f4cb1355900 CR3: 00000001175e2000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
0: 84 c0 test %al,%al
2: 74 06 je 0xa
4: 0f 8e ca 0b 00 00 jle 0xbd4
a: 48 8b 44 24 20 mov 0x20(%rsp),%rax
f: 48 8d 7b 02 lea 0x2(%rbx),%rdi
13: 48 89 fa mov %rdi,%rdx
16: 40 88 a8 48 02 00 00 mov %bpl,0x248(%rax)
1d: b8 ff ff 37 00 mov $0x37ffff,%eax
22: 48 c1 ea 03 shr $0x3,%rdx
26: 48 c1 e0 2a shl $0x2a,%rax
* 2a: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <-- trapping instruction
2e: 48 89 fa mov %rdi,%rdx
31: 83 e2 07 and $0x7,%edx
34: 38 d0 cmp %dl,%al
36: 7f 08 jg 0x40
38: 84 c0 test %al,%al
3a: 0f 85 9e 0b 00 00 jne 0xbde


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