KASAN: null-ptr-deref Write in submit_audio_out_urb (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    7829a896 usb-fuzzer: main usb gadget fuzzer driver
git tree:       https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=12f335e9a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f6d4561982f71f63
dashboard link: https://syzkaller.appspot.com/bug?extid=219f00fb49874dcaea17
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1122b6f3a00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=127fc823a00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+219f00fb49874dcaea17@xxxxxxxxxxxxxxxxxxxxxxxxx

snd_usb_toneport 1-1:0.49: write failed (error 0)
usb 1-1: send failed (error -110)
usb 1-1: send failed (error -110)
snd_usb_toneport 1-1:0.49: Line 6 POD Studio UX1 now attached
==================================================================
BUG: KASAN: null-ptr-deref in memset include/linux/string.h:344 [inline]
BUG: KASAN: null-ptr-deref in submit_audio_out_urb+0x919/0x1780  
sound/usb/line6/playback.c:242
Write of size 20 at addr 0000000000000010 by task kworker/1:0/17

CPU: 1 PID: 17 Comm: kworker/1:0 Not tainted 5.2.0-rc6+ #13
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: events line6_startup_work
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xca/0x13e lib/dump_stack.c:113
 __kasan_report.cold+0x5/0x32 mm/kasan/report.c:321
 kasan_report+0xe/0x20 mm/kasan/common.c:614
 memset+0x20/0x40 mm/kasan/common.c:107
 memset include/linux/string.h:344 [inline]
 submit_audio_out_urb+0x919/0x1780 sound/usb/line6/playback.c:242
 line6_submit_audio_out_all_urbs+0xc9/0x120 sound/usb/line6/playback.c:291
 line6_stream_start+0x156/0x1f0 sound/usb/line6/pcm.c:195
 line6_pcm_acquire+0x134/0x210 sound/usb/line6/pcm.c:318
 line6_startup_work+0x42/0x50 sound/usb/line6/driver.c:725
 process_one_work+0x905/0x1570 kernel/workqueue.c:2269
 worker_thread+0x96/0xe20 kernel/workqueue.c:2415
 kthread+0x30b/0x410 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 17 Comm: kworker/1:0 Tainted: G    B             5.2.0-rc6+ #13
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: events line6_startup_work
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xca/0x13e lib/dump_stack.c:113
 panic+0x292/0x6c9 kernel/panic.c:219
 end_report+0x43/0x49 mm/kasan/report.c:95
 __kasan_report.cold+0xd/0x32 mm/kasan/report.c:324
 kasan_report+0xe/0x20 mm/kasan/common.c:614
 memset+0x20/0x40 mm/kasan/common.c:107
 memset include/linux/string.h:344 [inline]
 submit_audio_out_urb+0x919/0x1780 sound/usb/line6/playback.c:242
 line6_submit_audio_out_all_urbs+0xc9/0x120 sound/usb/line6/playback.c:291
 line6_stream_start+0x156/0x1f0 sound/usb/line6/pcm.c:195
 line6_pcm_acquire+0x134/0x210 sound/usb/line6/pcm.c:318
 line6_startup_work+0x42/0x50 sound/usb/line6/driver.c:725
 process_one_work+0x905/0x1570 kernel/workqueue.c:2269
 worker_thread+0x96/0xe20 kernel/workqueue.c:2415
 kthread+0x30b/0x410 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..


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