syzbot

em28xx 5-1:0.161: Disconnecting em28xx
em28xx 5-1:0.161: Closing input extension
==================================================================
BUG: KASAN: slab-use-after-free in media_device_unregister drivers/media/mc/mc-device.c:833 [inline]
BUG: KASAN: slab-use-after-free in media_device_unregister+0x59d/0x610 drivers/media/mc/mc-device.c:811
Read of size 8 at addr ffff88807b17c218 by task kworker/1:3/5844

CPU: 1 UID: 0 PID: 5844 Comm: kworker/1:3 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x156/0x4c9 mm/kasan/report.c:482
 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595
 media_device_unregister drivers/media/mc/mc-device.c:833 [inline]
 media_device_unregister+0x59d/0x610 drivers/media/mc/mc-device.c:811
 em28xx_unregister_media_device+0x4e/0xe0 drivers/media/usb/em28xx/em28xx-cards.c:3511
 em28xx_release_resources+0x79/0x1b0 drivers/media/usb/em28xx/em28xx-cards.c:3532
 em28xx_usb_disconnect.cold+0x17d/0x253 drivers/media/usb/em28xx/em28xx-cards.c:4201
 usb_unbind_interface+0x1dd/0x9e0 drivers/usb/core/driver.c:458
 device_remove drivers/base/dd.c:573 [inline]
 device_remove+0x12a/0x180 drivers/base/dd.c:565
 __device_release_driver drivers/base/dd.c:1284 [inline]
 device_release_driver_internal+0x42e/0x600 drivers/base/dd.c:1307
 bus_remove_device+0x22f/0x440 drivers/base/bus.c:616
 device_del+0x376/0x9b0 drivers/base/core.c:3878
 usb_disable_device+0x367/0x810 drivers/usb/core/message.c:1418
 usb_disconnect+0x2e2/0x9a0 drivers/usb/core/hub.c:2345
 hub_port_connect drivers/usb/core/hub.c:5407 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x1d0c/0x4af0 drivers/usb/core/hub.c:5953
 process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275
 process_scheduled_works kernel/workqueue.c:3358 [inline]
 worker_thread+0x5da/0xe40 kernel/workqueue.c:3439
 kthread+0x370/0x450 kernel/kthread.c:467
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 5874:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kmalloc_noprof include/linux/slab.h:962 [inline]
 kzalloc_noprof include/linux/slab.h:1204 [inline]
 em28xx_v4l2_init.cold+0x94/0x3503 drivers/media/usb/em28xx/em28xx-video.c:2532
 em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1117
 request_module_async+0x61/0x80 drivers/media/usb/em28xx/em28xx-cards.c:3457
 process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275
 process_scheduled_works kernel/workqueue.c:3358 [inline]
 worker_thread+0x5da/0xe40 kernel/workqueue.c:3439
 kthread+0x370/0x450 kernel/kthread.c:467
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 5874:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2687 [inline]
 slab_free mm/slub.c:6124 [inline]
 kfree+0x1f6/0x6b0 mm/slub.c:6442
 kref_put.isra.0+0x56/0x90 include/linux/kref.h:65
 em28xx_v4l2_init.cold+0x280/0x3503 drivers/media/usb/em28xx/em28xx-video.c:2901
 em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1117
 request_module_async+0x61/0x80 drivers/media/usb/em28xx/em28xx-cards.c:3457
 process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275
 process_scheduled_works kernel/workqueue.c:3358 [inline]
 worker_thread+0x5da/0xe40 kernel/workqueue.c:3439
 kthread+0x370/0x450 kernel/kthread.c:467
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff88807b17c000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 536 bytes inside of
 freed 8192-byte region [ffff88807b17c000, ffff88807b17e000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7b178
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813fe3b280 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813fe3b280 dead000000000122 0000000000000000
head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0001ec5e01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 9232, tgid 9231 (syz.3.830), ts 375618678076, free_ts 375604451668
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3255 [inline]
 allocate_slab mm/slub.c:3444 [inline]
 new_slab+0xa6/0x6d0 mm/slub.c:3502
 refill_objects+0x26b/0x400 mm/slub.c:7134
 refill_sheaf mm/slub.c:2804 [inline]
 alloc_full_sheaf mm/slub.c:2825 [inline]
 __pcs_replace_empty_main+0x19f/0x600 mm/slub.c:4588
 alloc_from_pcs mm/slub.c:4681 [inline]
 slab_alloc_node mm/slub.c:4815 [inline]
 __do_kmalloc_node mm/slub.c:5218 [inline]
 __kmalloc_noprof+0x688/0x850 mm/slub.c:5231
 kmalloc_noprof include/linux/slab.h:966 [inline]
 kmalloc_array_noprof include/linux/slab.h:1113 [inline]
 snd_seq_oss_readq_new+0x96/0x2c0 sound/core/seq/oss/seq_oss_readq.c:41
 snd_seq_oss_open+0x476/0xa10 sound/core/seq/oss/seq_oss_init.c:226
 odev_open+0x79/0xc0 sound/core/seq/oss/seq_oss.c:128
 soundcore_open+0x2e3/0x5a0 sound/sound_core.c:594
 chrdev_open+0x234/0x6a0 fs/char_dev.c:411
 do_dentry_open+0x6d8/0x1660 fs/open.c:949
 vfs_open+0x82/0x3f0 fs/open.c:1081
 do_open fs/namei.c:4671 [inline]
 path_openat+0x208c/0x31a0 fs/namei.c:4830
 do_file_open+0x20e/0x430 fs/namei.c:4859
page last free pid 9231 tgid 9231 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4501 [inline]
 slab_alloc_node mm/slub.c:4830 [inline]
 __do_kmalloc_node mm/slub.c:5218 [inline]
 __kvmalloc_node_noprof+0x316/0xa00 mm/slub.c:6711
 simple_xattr_alloc+0x4a/0xa0 fs/xattr.c:1221
 shmem_initxattrs+0x225/0x570 mm/shmem.c:4280
 security_inode_init_security+0x242/0x370 security/security.c:1344
 shmem_symlink+0x15f/0xa00 mm/shmem.c:4122
 vfs_symlink fs/namei.c:5615 [inline]
 vfs_symlink+0x178/0x4d0 fs/namei.c:5594
 filename_symlinkat+0x2a6/0x560 fs/namei.c:5640
 __do_sys_symlinkat fs/namei.c:5660 [inline]
 __se_sys_symlinkat fs/namei.c:5655 [inline]
 __x64_sys_symlinkat+0x9c/0xe0 fs/namei.c:5655
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88807b17c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807b17c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807b17c200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88807b17c280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807b17c300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================