==================================================================
BUG: KASAN: use-after-free in dvb_device_open+0xc5/0x360 drivers/media/dvb-core/dvbdev.c:99
Read of size 8 at addr ffff888141e59218 by task syz.5.2847/14397

CPU: 0 PID: 14397 Comm: syz.5.2847 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:420
 kasan_report+0x10b/0x140 mm/kasan/report.c:524
 dvb_device_open+0xc5/0x360 drivers/media/dvb-core/dvbdev.c:99
 chrdev_open+0x585/0x5f0 fs/char_dev.c:414
 do_dentry_open+0x7dd/0x10b0 fs/open.c:882
 do_open fs/namei.c:3634 [inline]
 path_openat+0x2674/0x2f10 fs/namei.c:3791
 do_filp_open+0x1ee/0x420 fs/namei.c:3818
 do_sys_openat2+0x14b/0x4f0 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f944335e90e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007f94441c1b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f94441c26c0 RCX: 00007f944335e90e
RDX: 0000000000040402 RSI: 00007f94441c1c00 RDI: ffffffffffffff9c
RBP: 00007f94441c1c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f9443626308 R14: 00007f9443626270 R15: 00007ffe8d49a378
 </TASK>

Allocated by task 6802:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384
 kmalloc include/linux/slab.h:563 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 snd_seq_oss_midi_check_new_port+0x148/0x6d0 sound/core/seq/oss/seq_oss_midi.c:166
 receive_announce+0x281/0x370 sound/core/seq/oss/seq_oss_init.c:137
 snd_seq_deliver_single_event+0x806/0xb30 sound/core/seq/seq_clientmgr.c:663
 deliver_to_subscribers sound/core/seq/seq_clientmgr.c:720 [inline]
 snd_seq_deliver_event+0x49d/0x8c0 sound/core/seq/seq_clientmgr.c:854
 snd_seq_kernel_client_dispatch+0x1fc/0x2f0 sound/core/seq/seq_clientmgr.c:2406
 snd_seq_system_broadcast+0xf1/0x150 sound/core/seq/seq_system.c:86
 snd_seq_ioctl_create_port+0x4f9/0x640 sound/core/seq/seq_clientmgr.c:1399
 snd_seq_midisynth_probe+0xb26/0x1610 sound/core/seq/seq_midi.c:418
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x24a/0xb40 drivers/base/dd.c:638
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
 __device_attach_driver+0x2c6/0x510 drivers/base/dd.c:962
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a7/0x480 drivers/base/dd.c:1034
 bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
 device_add+0xbcf/0x1050 drivers/base/core.c:3712
 snd_seq_device_dev_register+0x3f/0xd0 sound/core/seq_device.c:170
 __snd_device_register sound/core/device.c:149 [inline]
 snd_device_register+0x124/0x1b0 sound/core/device.c:179
 snd_rawmidi_dev_register+0x93f/0xe50 sound/core/rawmidi.c:2005
 __snd_device_register sound/core/device.c:149 [inline]
 snd_device_register_all+0xc8/0x190 sound/core/device.c:197
 snd_card_register+0x1b0/0x6e0 sound/core/init.c:918
 try_to_register_card+0x2c9/0x350 sound/usb/card.c:-1
 usb_audio_probe+0x18e9/0x1e70 sound/usb/card.c:930
 usb_probe_interface+0x5be/0xae0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x24a/0xb40 drivers/base/dd.c:638
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
 __device_attach_driver+0x2c6/0x510 drivers/base/dd.c:962
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a7/0x480 drivers/base/dd.c:1034
 bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
 device_add+0xbcf/0x1050 drivers/base/core.c:3712
 usb_set_configuration+0x19d5/0x2030 drivers/usb/core/message.c:2223
 usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
 usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x24a/0xb40 drivers/base/dd.c:638
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
 __device_attach_driver+0x2c6/0x510 drivers/base/dd.c:962
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a7/0x480 drivers/base/dd.c:1034
 bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
 device_add+0xbcf/0x1050 drivers/base/core.c:3712
 usb_new_device+0xa01/0x15e0 drivers/usb/core/hub.c:2659
 hub_port_connect drivers/usb/core/hub.c:5517 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5657 [inline]
 port_event drivers/usb/core/hub.c:5817 [inline]
 hub_event+0x2b2f/0x5200 drivers/usb/core/hub.c:5899
 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Freed by task 6802:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516
 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 __kmem_cache_free+0xb6/0x200 mm/slub.c:3700
 snd_seq_oss_midi_check_exit_port+0x100/0x1e0 sound/core/seq/oss/seq_oss_midi.c:232
 receive_announce+0x2c3/0x370 sound/core/seq/oss/seq_oss_init.c:143
 snd_seq_deliver_single_event+0x806/0xb30 sound/core/seq/seq_clientmgr.c:663
 deliver_to_subscribers sound/core/seq/seq_clientmgr.c:720 [inline]
 snd_seq_deliver_event+0x49d/0x8c0 sound/core/seq/seq_clientmgr.c:854
 snd_seq_kernel_client_dispatch+0x1fc/0x2f0 sound/core/seq/seq_clientmgr.c:2406
 snd_seq_system_broadcast+0xf1/0x150 sound/core/seq/seq_system.c:86
 snd_seq_ioctl_delete_port+0xd9/0x190 sound/core/seq/seq_clientmgr.c:1419
 snd_seq_event_port_detach+0xe1/0x160 sound/core/seq/seq_ports.c:705
 snd_seq_midisynth_delete sound/core/seq/seq_midi.c:288 [inline]
 snd_seq_midisynth_remove+0x1e3/0x4f0 sound/core/seq/seq_midi.c:470
 device_remove drivers/base/dd.c:549 [inline]
 __device_release_driver drivers/base/dd.c:1279 [inline]
 device_release_driver_internal+0x4cf/0x7c0 drivers/base/dd.c:1305
 bus_remove_device+0x2dd/0x400 drivers/base/bus.c:531
 device_del+0x63f/0xa80 drivers/base/core.c:3900
 snd_seq_device_dev_disconnect+0x39/0x40 sound/core/seq_device.c:182
 __snd_device_disconnect sound/core/device.c:63 [inline]
 snd_device_disconnect_all+0xcf/0x200 sound/core/device.c:215
 snd_card_disconnect+0x385/0x810 sound/core/init.c:538
 snd_card_free_when_closed sound/core/init.c:630 [inline]
 snd_card_free+0x11c/0x1e0 sound/core/init.c:666
 usb_audio_probe+0x1970/0x1e70 sound/usb/card.c:939
 usb_probe_interface+0x5be/0xae0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x24a/0xb40 drivers/base/dd.c:638
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
 __device_attach_driver+0x2c6/0x510 drivers/base/dd.c:962
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a7/0x480 drivers/base/dd.c:1034
 bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
 device_add+0xbcf/0x1050 drivers/base/core.c:3712
 usb_set_configuration+0x19d5/0x2030 drivers/usb/core/message.c:2223
 usb_generic_driver_probe+0x89/0x150 drivers/usb/core/generic.c:238
 usb_probe_device+0x126/0x250 drivers/usb/core/driver.c:293
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x24a/0xb40 drivers/base/dd.c:638
 __driver_probe_device+0x1f5/0x390 drivers/base/dd.c:804
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:834
 __device_attach_driver+0x2c6/0x510 drivers/base/dd.c:962
 bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
 __device_attach+0x2a7/0x480 drivers/base/dd.c:1034
 bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
 device_add+0xbcf/0x1050 drivers/base/core.c:3712
 usb_new_device+0xa01/0x15e0 drivers/usb/core/hub.c:2659
 hub_port_connect drivers/usb/core/hub.c:5517 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5657 [inline]
 port_event drivers/usb/core/hub.c:5817 [inline]
 hub_event+0x2b2f/0x5200 drivers/usb/core/hub.c:5899
 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

The buggy address belongs to the object at ffff888141e59200
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 24 bytes inside of
 256-byte region [ffff888141e59200, ffff888141e59300)

The buggy address belongs to the physical page:
page:ffffea0005079600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x141e58
head:ffffea0005079600 order:1 compound_mapcount:0 compound_pincount:0
flags: 0x57ff00000010200(slab|head|node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000010200 ffffea0001e83880 dead000000000006 ffff888017441b40
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 16838377827, free_ts 0
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2560
 prep_new_page mm/page_alloc.c:2567 [inline]
 get_page_from_freelist+0x206b/0x2180 mm/page_alloc.c:4358
 __alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5658
 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2115
 alloc_slab_page+0x5d/0x180 mm/slub.c:1799
 allocate_slab mm/slub.c:1944 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:1997
 ___slab_alloc+0xbc5/0x1240 mm/slub.c:3154
 __slab_alloc mm/slub.c:3240 [inline]
 slab_alloc_node mm/slub.c:3325 [inline]
 __kmem_cache_alloc_node+0x126/0x270 mm/slub.c:3398
 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026
 kmalloc include/linux/slab.h:563 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 bus_add_driver+0xdc/0x5d0 drivers/base/bus.c:604
 driver_register+0x32d/0x430 drivers/base/driver.c:246
 usb_register_driver+0x201/0x3c0 drivers/usb/core/driver.c:1062
 uvc_init+0x23/0x4a drivers/media/usb/uvc/uvc_driver.c:3119
 do_one_initcall+0x257/0x800 init/main.c:1309
 do_initcall_level+0x13d/0x1ed init/main.c:1382
 do_initcalls+0x4b/0x8a init/main.c:1398
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888141e59100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888141e59180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888141e59200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888141e59280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888141e59300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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