================================================================== BUG: KASAN: use-after-free in v4l2_fh_init drivers/media/v4l2-core/v4l2-fh.c:25 [inline] BUG: KASAN: use-after-free in v4l2_fh_open+0xc6/0x430 drivers/media/v4l2-core/v4l2-fh.c:63 Read of size 8 at addr ffff8880590c4900 by task v4l_id/6688 CPU: 1 PID: 6688 Comm: v4l_id Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 print_address_description+0x60/0x2d0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0xdf/0x130 mm/kasan/report.c:451 v4l2_fh_init drivers/media/v4l2-core/v4l2-fh.c:25 [inline] v4l2_fh_open+0xc6/0x430 drivers/media/v4l2-core/v4l2-fh.c:63 em28xx_v4l2_open+0x152/0x990 drivers/media/usb/em28xx/em28xx-video.c:2163 v4l2_open+0x20b/0x360 drivers/media/v4l2-core/v4l2-dev.c:427 chrdev_open+0x597/0x670 fs/char_dev.c:414 do_dentry_open+0x7ff/0xf80 fs/open.c:826 do_open fs/namei.c:3608 [inline] path_openat+0x2682/0x2f30 fs/namei.c:3742 do_filp_open+0x1b3/0x3e0 fs/namei.c:3769 do_sys_openat2+0x142/0x4a0 fs/open.c:1253 do_sys_open fs/open.c:1269 [inline] __do_sys_openat fs/open.c:1285 [inline] __se_sys_openat fs/open.c:1280 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1280 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f764ccfd407 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:00007ffd4933e800 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f764cc0f880 RCX: 00007f764ccfd407 RDX: 0000000000000000 RSI: 00007ffd4933ff19 RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffd4933ea50 R14: 00007f764d48b000 R15: 000056223eb144d8 Allocated by task 6682: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522 kmalloc_reserve net/core/skbuff.c:356 [inline] pskb_expand_head+0x127/0x10f0 net/core/skbuff.c:1709 __bpf_try_make_writable net/core/filter.c:1667 [inline] bpf_try_make_writable net/core/filter.c:1673 [inline] bpf_try_make_head_writable net/core/filter.c:1681 [inline] ____bpf_clone_redirect net/core/filter.c:2447 [inline] bpf_clone_redirect+0x10f/0x390 net/core/filter.c:2423 bpf_prog_d583a5697f17c988+0x19/0x7ac bpf_dispatcher_nop_func include/linux/bpf.h:888 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] bpf_test_run+0x292/0x7d0 net/bpf/test_run.c:119 bpf_prog_test_run_skb+0x9cc/0x1180 net/bpf/test_run.c:669 bpf_prog_test_run+0x31e/0x390 kernel/bpf/syscall.c:3374 __sys_bpf+0x535/0x670 kernel/bpf/syscall.c:4675 __do_sys_bpf kernel/bpf/syscall.c:4761 [inline] __se_sys_bpf kernel/bpf/syscall.c:4759 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Freed by task 6682: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1710 [inline] slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736 slab_free mm/slub.c:3504 [inline] kfree+0xef/0x2a0 mm/slub.c:4564 skb_free_head net/core/skbuff.c:655 [inline] skb_release_data+0x6fe/0x850 net/core/skbuff.c:677 skb_release_all net/core/skbuff.c:742 [inline] __kfree_skb net/core/skbuff.c:756 [inline] kfree_skb_reason+0xaf/0x110 net/core/skbuff.c:776 kfree_skb include/linux/skbuff.h:1118 [inline] sit_tunnel_xmit+0x455/0x2250 net/ipv6/sit.c:1097 __netdev_start_xmit include/linux/netdevice.h:5027 [inline] netdev_start_xmit include/linux/netdevice.h:5041 [inline] xmit_one net/core/dev.c:3649 [inline] dev_hard_start_xmit+0x2a5/0x7e0 net/core/dev.c:3665 __dev_queue_xmit+0x19df/0x2ed0 net/core/dev.c:4288 __bpf_tx_skb net/core/filter.c:2127 [inline] __bpf_redirect_no_mac net/core/filter.c:2161 [inline] __bpf_redirect+0x6ad/0xee0 net/core/filter.c:2184 ____bpf_clone_redirect net/core/filter.c:2453 [inline] bpf_clone_redirect+0x241/0x390 net/core/filter.c:2423 bpf_prog_d583a5697f17c988+0x19/0x7ac bpf_dispatcher_nop_func include/linux/bpf.h:888 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] bpf_test_run+0x292/0x7d0 net/bpf/test_run.c:119 bpf_prog_test_run_skb+0x9cc/0x1180 net/bpf/test_run.c:669 bpf_prog_test_run+0x31e/0x390 kernel/bpf/syscall.c:3374 __sys_bpf+0x535/0x670 kernel/bpf/syscall.c:4675 __do_sys_bpf kernel/bpf/syscall.c:4761 [inline] __se_sys_bpf kernel/bpf/syscall.c:4759 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 The buggy address belongs to the object at ffff8880590c4800 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 256 bytes inside of 512-byte region [ffff8880590c4800, ffff8880590c4a00) The buggy address belongs to the page: page:ffffea0001643100 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x590c4 head:ffffea0001643100 order:2 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888016841c80 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d2a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 6682, ts 155207152611, free_ts 155182685585 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192 __alloc_pages+0x1e1/0x470 mm/page_alloc.c:5487 alloc_slab_page mm/slub.c:1780 [inline] allocate_slab mm/slub.c:1917 [inline] new_slab+0xc0/0x4b0 mm/slub.c:1980 ___slab_alloc+0x81e/0xdf0 mm/slub.c:3013 __slab_alloc mm/slub.c:3100 [inline] slab_alloc_node mm/slub.c:3191 [inline] __kmalloc_node_track_caller+0x1fc/0x3a0 mm/slub.c:4963 kmalloc_reserve net/core/skbuff.c:356 [inline] pskb_expand_head+0x127/0x10f0 net/core/skbuff.c:1709 __bpf_try_make_writable net/core/filter.c:1667 [inline] bpf_try_make_writable net/core/filter.c:1673 [inline] bpf_try_make_head_writable net/core/filter.c:1681 [inline] ____bpf_clone_redirect net/core/filter.c:2447 [inline] bpf_clone_redirect+0x10f/0x390 net/core/filter.c:2423 bpf_prog_d583a5697f17c988+0x19/0x7ac bpf_dispatcher_nop_func include/linux/bpf.h:888 [inline] __bpf_prog_run include/linux/filter.h:628 [inline] bpf_prog_run include/linux/filter.h:635 [inline] bpf_test_run+0x292/0x7d0 net/bpf/test_run.c:119 bpf_prog_test_run_skb+0x9cc/0x1180 net/bpf/test_run.c:669 bpf_prog_test_run+0x31e/0x390 kernel/bpf/syscall.c:3374 __sys_bpf+0x535/0x670 kernel/bpf/syscall.c:4675 __do_sys_bpf kernel/bpf/syscall.c:4761 [inline] __se_sys_bpf kernel/bpf/syscall.c:4759 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1340 [inline] free_pcp_prepare mm/page_alloc.c:1391 [inline] free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317 free_unref_page+0x94/0x280 mm/page_alloc.c:3396 free_nonslab_page+0xe2/0x150 mm/slub.c:3540 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2128 [inline] kref_put include/linux/kref.h:65 [inline] em28xx_v4l2_init+0x1649/0x2e50 drivers/media/usb/em28xx/em28xx-video.c:2911 em28xx_init_extension+0x118/0x1b0 drivers/media/usb/em28xx/em28xx-core.c:1126 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 process_scheduled_works kernel/workqueue.c:2373 [inline] worker_thread+0xd76/0x12a0 kernel/workqueue.c:2462 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Memory state around the buggy address: ffff8880590c4800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880590c4880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880590c4900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880590c4980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880590c4a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================