Hello,

syzbot found the following crash on:

HEAD commit: 9a33b369 usb-fuzzer: main usb gadget fuzzer driver git tree: https://github.com/google/kasan/tree/usb-fuzzer console output: https://syzkaller.appspot.com/x/log.txt?x=14153823200000 kernel config: https://syzkaller.appspot.com/x/.config?x=23e37f59d94ddd15 dashboard link: https://syzkaller.appspot.com/bug?extid=48df349490c36f9f54ab compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12642f97200000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14a8f5af200000

IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+48df349490c36f9f54ab@syzkaller.appspotmail.com

snd_usb_toneport: probe of 1-1:0.0 failed with error -71 snd_usb_toneport: probe of 5-1:0.0 failed with error -71 usb 1-1: USB disconnect, device number 72 snd_usb_toneport: probe of 4-1:0.0 failed with error -71 ================================================================== BUG: KASAN: use-after-free in __list_del_entry_valid+0xe0/0xef lib/list_debug.c:51 Read of size 8 at addr ffff88809b8339a8 by task kworker/0:4/5492

CPU: 0 PID: 5492 Comm: kworker/0:4 Not tainted 5.1.0-rc4-319354-g9a33b36 #3 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+0xe8/0x16e lib/dump_stack.c:113 print_address_description+0x6c/0x236 mm/kasan/report.c:187 kasan_report.cold+0x1a/0x3c mm/kasan/report.c:317 __list_del_entry_valid+0xe0/0xef lib/list_debug.c:51 __list_del_entry include/linux/list.h:117 [inline] list_del include/linux/list.h:125 [inline] snd_info_free_entry+0x137/0x340 sound/core/info.c:795 snd_info_card_free+0x43/0x90 sound/core/info.c:606 snd_card_do_free sound/core/init.c:469 [inline] release_card_device+0x8b/0x100 sound/core/init.c:156 device_release+0x7d/0x210 drivers/base/core.c:1064 kobject_cleanup lib/kobject.c:662 [inline] kobject_release lib/kobject.c:691 [inline] kref_put include/linux/kref.h:67 [inline] kobject_put+0x1df/0x4f0 lib/kobject.c:708 put_device+0x21/0x30 drivers/base/core.c:2205 snd_card_free_when_closed+0x3a/0x50 sound/core/init.c:493 line6_disconnect.cold+0xa3/0xbc sound/usb/line6/driver.c:833 line6_probe+0xb23/0x1150 sound/usb/line6/driver.c:799 usb_probe_interface+0x31d/0x820 drivers/usb/core/driver.c:361 really_probe+0x2da/0xb10 drivers/base/dd.c:509 driver_probe_device+0x21d/0x350 drivers/base/dd.c:671 __device_attach_driver+0x1d8/0x290 drivers/base/dd.c:778 bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:454 __device_attach+0x223/0x3a0 drivers/base/dd.c:844 bus_probe_device+0x1f1/0x2a0 drivers/base/bus.c:514 device_add+0xad2/0x16e0 drivers/base/core.c:2106 usb_set_configuration+0xdf7/0x1740 drivers/usb/core/message.c:2021 generic_probe+0xa2/0xda drivers/usb/core/generic.c:210 usb_probe_device+0xc0/0x150 drivers/usb/core/driver.c:266 really_probe+0x2da/0xb10 drivers/base/dd.c:509 driver_probe_device+0x21d/0x350 drivers/base/dd.c:671 __device_attach_driver+0x1d8/0x290 drivers/base/dd.c:778 bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:454 __device_attach+0x223/0x3a0 drivers/base/dd.c:844 bus_probe_device+0x1f1/0x2a0 drivers/base/bus.c:514 device_add+0xad2/0x16e0 drivers/base/core.c:2106 usb_new_device.cold+0x537/0xccf drivers/usb/core/hub.c:2534 hub_port_connect drivers/usb/core/hub.c:5089 [inline] hub_port_connect_change drivers/usb/core/hub.c:5204 [inline] port_event drivers/usb/core/hub.c:5350 [inline] hub_event+0x138e/0x3b00 drivers/usb/core/hub.c:5432 process_one_work+0x90f/0x1580 kernel/workqueue.c:2269 process_scheduled_works kernel/workqueue.c:2331 [inline] worker_thread+0x7b0/0xe20 kernel/workqueue.c:2417 kthread+0x313/0x420 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Allocated by task 5: set_track mm/kasan/common.c:87 [inline] __kasan_kmalloc mm/kasan/common.c:497 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:470 kmalloc include/linux/slab.h:547 [inline] kzalloc include/linux/slab.h:742 [inline] snd_info_create_entry+0x56/0x400 sound/core/info.c:701 snd_info_create_module_entry sound/core/info.c:737 [inline] create_subdir+0x27/0xa0 sound/core/info.c:454 snd_info_card_create+0xcf/0x230 sound/core/info.c:528 snd_card_new+0x61d/0x920 sound/core/init.c:255 line6_probe+0x135/0x1150 sound/usb/line6/driver.c:736 usb_probe_interface+0x31d/0x820 drivers/usb/core/driver.c:361 really_probe+0x2da/0xb10 drivers/base/dd.c:509 driver_probe_device+0x21d/0x350 drivers/base/dd.c:671 __device_attach_driver+0x1d8/0x290 drivers/base/dd.c:778 bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:454 __device_attach+0x223/0x3a0 drivers/base/dd.c:844 bus_probe_device+0x1f1/0x2a0 drivers/base/bus.c:514 device_add+0xad2/0x16e0 drivers/base/core.c:2106 usb_set_configuration+0xdf7/0x1740 drivers/usb/core/message.c:2021 generic_probe+0xa2/0xda drivers/usb/core/generic.c:210 usb_probe_device+0xc0/0x150 drivers/usb/core/driver.c:266 really_probe+0x2da/0xb10 drivers/base/dd.c:509 driver_probe_device+0x21d/0x350 drivers/base/dd.c:671 __device_attach_driver+0x1d8/0x290 drivers/base/dd.c:778 bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:454 __device_attach+0x223/0x3a0 drivers/base/dd.c:844 bus_probe_device+0x1f1/0x2a0 drivers/base/bus.c:514 device_add+0xad2/0x16e0 drivers/base/core.c:2106 usb_new_device.cold+0x537/0xccf drivers/usb/core/hub.c:2534 hub_port_connect drivers/usb/core/hub.c:5089 [inline] hub_port_connect_change drivers/usb/core/hub.c:5204 [inline] port_event drivers/usb/core/hub.c:5350 [inline] hub_event+0x138e/0x3b00 drivers/usb/core/hub.c:5432 process_one_work+0x90f/0x1580 kernel/workqueue.c:2269 process_scheduled_works kernel/workqueue.c:2331 [inline] worker_thread+0x7b0/0xe20 kernel/workqueue.c:2417 kthread+0x313/0x420 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Freed by task 5: set_track mm/kasan/common.c:87 [inline] __kasan_slab_free+0x130/0x180 mm/kasan/common.c:459 slab_free_hook mm/slub.c:1429 [inline] slab_free_freelist_hook+0x5e/0x140 mm/slub.c:1456 slab_free mm/slub.c:3003 [inline] kfree+0xce/0x290 mm/slub.c:3958 snd_info_free_entry+0x29a/0x340 sound/core/info.c:799 snd_info_card_free+0x43/0x90 sound/core/info.c:606 snd_card_do_free sound/core/init.c:469 [inline] release_card_device+0x8b/0x100 sound/core/init.c:156 device_release+0x7d/0x210 drivers/base/core.c:1064 kobject_cleanup lib/kobject.c:662 [inline] kobject_release lib/kobject.c:691 [inline] kref_put include/linux/kref.h:67 [inline] kobject_put+0x1df/0x4f0 lib/kobject.c:708 put_device+0x21/0x30 drivers/base/core.c:2205 snd_card_free_when_closed+0x3a/0x50 sound/core/init.c:493 line6_disconnect.cold+0xa3/0xbc sound/usb/line6/driver.c:833 line6_probe+0xb23/0x1150 sound/usb/line6/driver.c:799 usb_probe_interface+0x31d/0x820 drivers/usb/core/driver.c:361 really_probe+0x2da/0xb10 drivers/base/dd.c:509 driver_probe_device+0x21d/0x350 drivers/base/dd.c:671 __device_attach_driver+0x1d8/0x290 drivers/base/dd.c:778 bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:454 __device_attach+0x223/0x3a0 drivers/base/dd.c:844 bus_probe_device+0x1f1/0x2a0 drivers/base/bus.c:514 device_add+0xad2/0x16e0 drivers/base/core.c:2106 usb_set_configuration+0xdf7/0x1740 drivers/usb/core/message.c:2021 generic_probe+0xa2/0xda drivers/usb/core/generic.c:210 usb_probe_device+0xc0/0x150 drivers/usb/core/driver.c:266 really_probe+0x2da/0xb10 drivers/base/dd.c:509 driver_probe_device+0x21d/0x350 drivers/base/dd.c:671 __device_attach_driver+0x1d8/0x290 drivers/base/dd.c:778 bus_for_each_drv+0x163/0x1e0 drivers/base/bus.c:454 __device_attach+0x223/0x3a0 drivers/base/dd.c:844 bus_probe_device+0x1f1/0x2a0 drivers/base/bus.c:514 device_add+0xad2/0x16e0 drivers/base/core.c:2106 usb_new_device.cold+0x537/0xccf drivers/usb/core/hub.c:2534 hub_port_connect drivers/usb/core/hub.c:5089 [inline] hub_port_connect_change drivers/usb/core/hub.c:5204 [inline] port_event drivers/usb/core/hub.c:5350 [inline] hub_event+0x138e/0x3b00 drivers/usb/core/hub.c:5432 process_one_work+0x90f/0x1580 kernel/workqueue.c:2269 process_scheduled_works kernel/workqueue.c:2331 [inline] worker_thread+0x7b0/0xe20 kernel/workqueue.c:2417 kthread+0x313/0x420 kernel/kthread.c:253 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff88809b8338c0 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 232 bytes inside of 256-byte region [ffff88809b8338c0, ffff88809b8339c0) The buggy address belongs to the page: page:ffffea00026e0cc0 count:1 mapcount:0 mapping:ffff88812c3f4e00 index:0x0 flags: 0xfff00000000200(slab) raw: 00fff00000000200 dead000000000100 dead000000000200 ffff88812c3f4e00 raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected

Memory state around the buggy address: ffff88809b833880: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff88809b833900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

ffff88809b833980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc

^ ffff88809b833a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809b833a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================

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