================================================================== BUG: KASAN: slab-use-after-free in v4l2_fh_init drivers/media/v4l2-core/v4l2-fh.c:25 [inline] BUG: KASAN: slab-use-after-free in v4l2_fh_open+0xac/0x420 drivers/media/v4l2-core/v4l2-fh.c:64 Read of size 8 at addr ffff888059c3c748 by task v4l_id/21936 CPU: 1 UID: 0 PID: 21936 Comm: v4l_id Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xba/0x230 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 v4l2_fh_init drivers/media/v4l2-core/v4l2-fh.c:25 [inline] v4l2_fh_open+0xac/0x420 drivers/media/v4l2-core/v4l2-fh.c:64 em28xx_v4l2_open+0x157/0x9a0 drivers/media/usb/em28xx/em28xx-video.c:2153 v4l2_open+0x1bf/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:433 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411 do_dentry_open+0x785/0x14e0 fs/open.c:949 vfs_open+0x3b/0x340 fs/open.c:1081 do_open fs/namei.c:4671 [inline] path_openat+0x2e08/0x3860 fs/namei.c:4830 do_file_open+0x23e/0x4a0 fs/namei.c:4859 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6e492a7407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007fff6a439410 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f6e49a1a880 RCX: 00007f6e492a7407 RDX: 0000000000000000 RSI: 00007fff6a439f1a RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007fff6a439660 R14: 00007f6e49b81000 R15: 000055d5739c84d8 Allocated by task 23059: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5358 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] em28xx_v4l2_init+0x10b/0x2e70 drivers/media/usb/em28xx/em28xx-video.c:2532 em28xx_init_extension+0x120/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1117 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 23059: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2692 [inline] slab_free mm/slub.c:6143 [inline] kfree+0x1c1/0x630 mm/slub.c:6461 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2118 [inline] kref_put include/linux/kref.h:65 [inline] em28xx_v4l2_init+0x1683/0x2e70 drivers/media/usb/em28xx/em28xx-video.c:2901 em28xx_init_extension+0x120/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1117 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 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 ffff888059c3c000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 1864 bytes inside of freed 8192-byte region [ffff888059c3c000, ffff888059c3e000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x59c38 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 ffff88813fea9280 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813fea9280 dead000000000100 dead000000000122 head: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0001670e01 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 5879, tgid 5879 (kworker/0:4), ts 92342192395, free_ts 92040599837 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3269 [inline] allocate_slab+0x77/0x660 mm/slub.c:3458 new_slab mm/slub.c:3516 [inline] refill_objects+0x331/0x3c0 mm/slub.c:7153 refill_sheaf mm/slub.c:2818 [inline] __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4592 alloc_from_pcs mm/slub.c:4695 [inline] slab_alloc_node mm/slub.c:4829 [inline] __do_kmalloc_node mm/slub.c:5237 [inline] __kmalloc_noprof+0x474/0x760 mm/slub.c:5250 usb_allocate_stream_buffers+0x11a/0x3f0 drivers/media/usb/dvb-usb/usb-urb.c:121 usb_bulk_urb_init drivers/media/usb/dvb-usb/usb-urb.c:142 [inline] usb_urb_init+0x91d/0x1380 drivers/media/usb/dvb-usb/usb-urb.c:229 dvb_usb_adapter_stream_init+0x210/0x4d0 drivers/media/usb/dvb-usb/dvb-usb-urb.c:108 dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:82 [inline] dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:186 [inline] dvb_usb_device_init+0x1bbe/0x2590 drivers/media/usb/dvb-usb/dvb-usb-init.c:310 cxusb_probe+0xd3/0x710 drivers/media/usb/dvb-usb/cxusb.c:1627 usb_probe_interface+0x668/0xc90 drivers/usb/core/driver.c:396 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x267/0xaf0 drivers/base/dd.c:661 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:803 driver_probe_device+0x4f/0x240 drivers/base/dd.c:833 page last free pid 5835 tgid 5835 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978 __slab_free+0x263/0x2b0 mm/slub.c:5551 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4515 [inline] slab_alloc_node mm/slub.c:4844 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4851 mt_alloc_one lib/maple_tree.c:174 [inline] mas_dup_build+0x141/0x1250 lib/maple_tree.c:6299 __mt_dup+0x197/0x2c0 lib/maple_tree.c:6382 dup_mmap+0x418/0x1d90 mm/mmap.c:1758 dup_mm kernel/fork.c:1530 [inline] copy_mm+0x13b/0x4b0 kernel/fork.c:1582 copy_process+0x18b6/0x3cf0 kernel/fork.c:2223 kernel_clone+0x248/0x8e0 kernel/fork.c:2654 __do_sys_clone kernel/fork.c:2795 [inline] __se_sys_clone kernel/fork.c:2779 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2779 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888059c3c600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888059c3c680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888059c3c700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888059c3c780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888059c3c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================