syzbot has found a reproducer for the following crash on: HEAD commit: 4cc301ee usb: gadget: add raw-gadget interface git tree: https://github.com/google/kasan.git usb-fuzzer console output: https://syzkaller.appspot.com/x/log.txt?x=17f5a721e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=9ba75825443d54bd dashboard link: https://syzkaller.appspot.com/bug?extid=75287f75e2fedd69d680 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16a0b6f1e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1327dd76e00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+75287f75e2fedd69d680@xxxxxxxxxxxxxxxxxxxxxxxxx usbvision_set_audio: can't write iopin register for audio switching usbvision_radio_close: Final disconnect ================================================================== BUG: KASAN: use-after-free in v4l2_release+0x2f1/0x390 drivers/media/v4l2-core/v4l2-dev.c:459 Read of size 4 at addr ffff8881caba1068 by task v4l_id/1913 CPU: 1 PID: 1913 Comm: v4l_id Not tainted 5.5.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xef/0x16e lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd3/0x314 mm/kasan/report.c:374 __kasan_report.cold+0x37/0x85 mm/kasan/report.c:506 kasan_report+0xe/0x20 mm/kasan/common.c:639 v4l2_release+0x2f1/0x390 drivers/media/v4l2-core/v4l2-dev.c:459 __fput+0x2d7/0x840 fs/file_table.c:280 task_work_run+0x13f/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x1d2/0x200 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_64+0x4e0/0x5a0 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7fbeb0b822b0 Code: 40 75 0b 31 c0 48 83 c4 08 e9 0c ff ff ff 48 8d 3d c5 32 08 00 e8 c0 07 02 00 83 3d 45 a3 2b 00 00 75 10 b8 03 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ce 8a 01 00 48 89 04 24 RSP: 002b:00007ffe52d6b158 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007fbeb0b822b0 RDX: 0000000000000013 RSI: 0000000080685600 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000400884 R13: 00007ffe52d6b2b0 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 94: save_stack+0x1b/0x80 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] __kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:486 kmalloc include/linux/slab.h:556 [inline] kzalloc include/linux/slab.h:670 [inline] usbvision_alloc drivers/media/usb/usbvision/usbvision-video.c:1315 [inline] usbvision_probe.cold+0x5c5/0x1f21 drivers/media/usb/usbvision/usbvision-video.c:1469 usb_probe_interface+0x310/0x800 drivers/usb/core/driver.c:361 really_probe+0x290/0xad0 drivers/base/dd.c:548 driver_probe_device+0x223/0x350 drivers/base/dd.c:721 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:828 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430 __device_attach+0x217/0x390 drivers/base/dd.c:894 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490 device_add+0x1459/0x1bf0 drivers/base/core.c:2487 usb_set_configuration+0xe47/0x17d0 drivers/usb/core/message.c:2023 generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210 usb_probe_device+0xaf/0x140 drivers/usb/core/driver.c:266 really_probe+0x290/0xad0 drivers/base/dd.c:548 driver_probe_device+0x223/0x350 drivers/base/dd.c:721 __device_attach_driver+0x1d1/0x290 drivers/base/dd.c:828 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430 __device_attach+0x217/0x390 drivers/base/dd.c:894 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490 device_add+0x1459/0x1bf0 drivers/base/core.c:2487 usb_new_device.cold+0x540/0xcd0 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+0x21cb/0x4300 drivers/usb/core/hub.c:5552 process_one_work+0x945/0x15c0 kernel/workqueue.c:2264 process_scheduled_works kernel/workqueue.c:2326 [inline] worker_thread+0x7ab/0xe20 kernel/workqueue.c:2412 kthread+0x318/0x420 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Freed by task 1913: save_stack+0x1b/0x80 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:335 [inline] __kasan_slab_free+0x117/0x160 mm/kasan/common.c:474 slab_free_hook mm/slub.c:1425 [inline] slab_free_freelist_hook mm/slub.c:1458 [inline] slab_free mm/slub.c:3005 [inline] kfree+0xd5/0x300 mm/slub.c:3957 usbvision_release+0x181/0x1c0 drivers/media/usb/usbvision/usbvision-video.c:1364 usbvision_radio_close.cold+0x2b/0x74 drivers/media/usb/usbvision/usbvision-video.c:1130 v4l2_release+0x2e7/0x390 drivers/media/v4l2-core/v4l2-dev.c:455 __fput+0x2d7/0x840 fs/file_table.c:280 task_work_run+0x13f/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x1d2/0x200 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_64+0x4e0/0x5a0 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8881caba0000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 4200 bytes inside of 8192-byte region [ffff8881caba0000, ffff8881caba2000) The buggy address belongs to the page: page:ffffea00072ae800 refcount:1 mapcount:0 mapping:ffff8881da00c500 index:0x0 compound_mapcount: 0 raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881da00c500 raw: 0000000000000000 0000000080020002 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881caba0f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881caba0f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881caba1000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881caba1080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881caba1100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================
