syzbot

usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 1-1: Product: syz
usb 1-1: Manufacturer: syz
usb 1-1: SerialNumber: syz
usb 1-1: 0:2 : does not exist
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BUG: KASAN: slab-out-of-bounds in uac_extension_unit_iExtension include/uapi/linux/usb/audio.h:483 [inline]
BUG: KASAN: slab-out-of-bounds in build_audio_procunit+0xeab/0x13f0 sound/usb/mixer.c:2434
Read of size 1 at addr ffff8881d4aaa735 by task kworker/1:2/83

CPU: 1 PID: 83 Comm: kworker/1:2 Not tainted 5.4.0-rc6+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xca/0x13e lib/dump_stack.c:113
 print_address_description.constprop.0+0x36/0x50 mm/kasan/report.c:374
 __kasan_report.cold+0x1a/0x33 mm/kasan/report.c:506
 kasan_report+0xe/0x20 mm/kasan/common.c:634
 uac_extension_unit_iExtension include/uapi/linux/usb/audio.h:483 [inline]
 build_audio_procunit+0xeab/0x13f0 sound/usb/mixer.c:2434
 parse_audio_extension_unit sound/usb/mixer.c:2483 [inline]
 parse_audio_unit+0x1812/0x36f0 sound/usb/mixer.c:2761
 snd_usb_mixer_controls+0x715/0xb90 sound/usb/mixer.c:3095
 snd_usb_create_mixer+0x2b5/0x1890 sound/usb/mixer.c:3445
 usb_audio_probe+0xc76/0x2010 sound/usb/card.c:653
 usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
 really_probe+0x281/0x6d0 drivers/base/dd.c:548
 driver_probe_device+0x104/0x210 drivers/base/dd.c:721
 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
 __device_attach+0x217/0x360 drivers/base/dd.c:894
 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
 device_add+0xae6/0x16f0 drivers/base/core.c:2202
 usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023
 generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
 usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
 really_probe+0x281/0x6d0 drivers/base/dd.c:548
 driver_probe_device+0x104/0x210 drivers/base/dd.c:721
 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
 __device_attach+0x217/0x360 drivers/base/dd.c:894
 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
 device_add+0xae6/0x16f0 drivers/base/core.c:2202
 usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2537
 hub_port_connect drivers/usb/core/hub.c:5184 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5324 [inline]
 port_event drivers/usb/core/hub.c:5470 [inline]
 hub_event+0x1df8/0x3800 drivers/usb/core/hub.c:5552
 process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
 worker_thread+0x96/0xe20 kernel/workqueue.c:2415
 kthread+0x318/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 83:
 save_stack+0x1b/0x80 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc mm/kasan/common.c:510 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:483
 kmalloc include/linux/slab.h:561 [inline]
 usb_get_configuration+0x311/0x3100 drivers/usb/core/config.c:862
 usb_enumerate_device drivers/usb/core/hub.c:2370 [inline]
 usb_new_device+0xd3/0x160 drivers/usb/core/hub.c:2506
 hub_port_connect drivers/usb/core/hub.c:5184 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5324 [inline]
 port_event drivers/usb/core/hub.c:5470 [inline]
 hub_event+0x1df8/0x3800 drivers/usb/core/hub.c:5552
 process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
 worker_thread+0x96/0xe20 kernel/workqueue.c:2415
 kthread+0x318/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 211:
 save_stack+0x1b/0x80 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 kasan_set_free_info mm/kasan/common.c:332 [inline]
 __kasan_slab_free+0x130/0x180 mm/kasan/common.c:471
 slab_free_hook mm/slub.c:1424 [inline]
 slab_free_freelist_hook mm/slub.c:1475 [inline]
 slab_free mm/slub.c:3025 [inline]
 kfree+0xe4/0x320 mm/slub.c:3977
 do_new_mount fs/namespace.c:2827 [inline]
 do_mount+0x68a/0x1bf0 fs/namespace.c:3143
 ksys_mount+0xd7/0x150 fs/namespace.c:3352
 __do_sys_mount fs/namespace.c:3366 [inline]
 __se_sys_mount fs/namespace.c:3363 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3363
 do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8881d4aaa600
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 53 bytes to the right of
 256-byte region [ffff8881d4aaa600, ffff8881d4aaa700)
The buggy address belongs to the page:
page:ffffea000752aa80 refcount:1 mapcount:0 mapping:ffff8881da002780 index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 ffffea000752c900 0000000a0000000a ffff8881da002780
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881d4aaa600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881d4aaa680: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
>ffff8881d4aaa700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                     ^
 ffff8881d4aaa780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881d4aaa800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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