Hello,

syzbot found the following issue on:

HEAD commit: 4641b323 Add linux-next specific files for 20210305 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=103252ead00000 kernel config: https://syzkaller.appspot.com/x/.config?x=b87b6a083d302a90 dashboard link: https://syzkaller.appspot.com/bug?extid=ffad4c74b3b3ea3aa9c3 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1122d35cd00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17f6476cd00000

The issue was bisected to:

commit 9799110825dba087c2bdce886977cf84dada2005 Author: Kai-Heng Feng kai.heng.feng@canonical.com Date: Thu Mar 4 04:34:16 2021 +0000

ALSA: usb-audio: Disable USB autosuspend properly in setup_disable_autosuspend()

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=166d91ead00000 final oops: https://syzkaller.appspot.com/x/report.txt?x=156d91ead00000 console output: https://syzkaller.appspot.com/x/log.txt?x=116d91ead00000

IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ffad4c74b3b3ea3aa9c3@syzkaller.appspotmail.com Fixes: 9799110825db ("ALSA: usb-audio: Disable USB autosuspend properly in setup_disable_autosuspend()")

usb 1-1: USB disconnect, device number 2 ================================================================== BUG: KASAN: use-after-free in usb_audio_disconnect+0x750/0x800 sound/usb/card.c:918 Read of size 2 at addr ffff888027a08f24 by task kworker/0:2/2966

CPU: 0 PID: 2966 Comm: kworker/0:2 Not tainted 5.12.0-rc1-next-20210305-syzkaller #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:79 [inline] dump_stack+0xfa/0x151 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232 __kasan_report mm/kasan/report.c:399 [inline] kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416 usb_audio_disconnect+0x750/0x800 sound/usb/card.c:918 usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:458 __device_release_driver+0x3bd/0x6f0 drivers/base/dd.c:1156 device_release_driver_internal drivers/base/dd.c:1187 [inline] device_release_driver+0x26/0x40 drivers/base/dd.c:1210 bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:533 device_del+0x502/0xd40 drivers/base/core.c:3421 usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1413 usb_disconnect.cold+0x27d/0x791 drivers/usb/core/hub.c:2218 hub_port_connect drivers/usb/core/hub.c:5074 [inline] hub_port_connect_change drivers/usb/core/hub.c:5363 [inline] port_event drivers/usb/core/hub.c:5509 [inline] hub_event+0x1c9c/0x4320 drivers/usb/core/hub.c:5591 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Allocated by task 5: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:427 [inline] ____kasan_kmalloc mm/kasan/common.c:506 [inline] ____kasan_kmalloc mm/kasan/common.c:465 [inline] __kasan_kmalloc+0x99/0xc0 mm/kasan/common.c:515 kmalloc include/linux/slab.h:561 [inline] kzalloc include/linux/slab.h:686 [inline] snd_card_new+0xc2/0xcb0 sound/core/init.c:176 snd_usb_audio_create sound/usb/card.c:588 [inline] usb_audio_probe+0x1547/0x2c70 sound/usb/card.c:755 usb_probe_interface+0x315/0x7f0 drivers/usb/core/driver.c:396 really_probe+0x291/0xe60 drivers/base/dd.c:554 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:740 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:846 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x4a0 drivers/base/dd.c:914 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xbdb/0x1db0 drivers/base/core.c:3242 usb_set_configuration+0x113f/0x1910 drivers/usb/core/message.c:2164 usb_generic_driver_probe+0xba/0x100 drivers/usb/core/generic.c:238 usb_probe_device+0xd9/0x2c0 drivers/usb/core/driver.c:293 really_probe+0x291/0xe60 drivers/base/dd.c:554 driver_probe_device+0x26b/0x3d0 drivers/base/dd.c:740 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:846 bus_for_each_drv+0x15f/0x1e0 drivers/base/bus.c:431 __device_attach+0x228/0x4a0 drivers/base/dd.c:914 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:491 device_add+0xbdb/0x1db0 drivers/base/core.c:3242 usb_new_device.cold+0x721/0x1058 drivers/usb/core/hub.c:2555 hub_port_connect drivers/usb/core/hub.c:5223 [inline] hub_port_connect_change drivers/usb/core/hub.c:5363 [inline] port_event drivers/usb/core/hub.c:5509 [inline] hub_event+0x2357/0x4320 drivers/usb/core/hub.c:5591 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Freed by task 2966: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:357 ____kasan_slab_free mm/kasan/common.c:360 [inline] ____kasan_slab_free mm/kasan/common.c:325 [inline] __kasan_slab_free+0xf5/0x130 mm/kasan/common.c:367 kasan_slab_free include/linux/kasan.h:199 [inline] slab_free_hook mm/slub.c:1562 [inline] slab_free_freelist_hook+0x72/0x1b0 mm/slub.c:1600 slab_free mm/slub.c:3161 [inline] kfree+0xe5/0x7b0 mm/slub.c:4215 device_release+0x9f/0x240 drivers/base/core.c:2108 kobject_cleanup lib/kobject.c:705 [inline] kobject_release lib/kobject.c:736 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1c8/0x540 lib/kobject.c:753 put_device+0x1b/0x30 drivers/base/core.c:3341 snd_card_free_when_closed+0x35/0x50 sound/core/init.c:518 usb_audio_disconnect+0x2ba/0x800 sound/usb/card.c:913 usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:458 __device_release_driver+0x3bd/0x6f0 drivers/base/dd.c:1156 device_release_driver_internal drivers/base/dd.c:1187 [inline] device_release_driver+0x26/0x40 drivers/base/dd.c:1210 bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:533 device_del+0x502/0xd40 drivers/base/core.c:3421 usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1413 usb_disconnect.cold+0x27d/0x791 drivers/usb/core/hub.c:2218 hub_port_connect drivers/usb/core/hub.c:5074 [inline] hub_port_connect_change drivers/usb/core/hub.c:5363 [inline] port_event drivers/usb/core/hub.c:5509 [inline] hub_event+0x1c9c/0x4320 drivers/usb/core/hub.c:5591 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

The buggy address belongs to the object at ffff888027a08000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 3876 bytes inside of 8192-byte region [ffff888027a08000, ffff888027a0a000) The buggy address belongs to the page: page:0000000024fc4526 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x27a08 head:0000000024fc4526 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head) raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888010842280 raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected

Memory state around the buggy address: ffff888027a08e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888027a08e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

ffff888027a08f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

^ ffff888027a08f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888027a09000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================

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