================================================================== BUG: KASAN: slab-use-after-free in v4l2_open+0x395/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:444 Read of size 4 at addr ffff88807ebbc860 by task v4l_id/28842 CPU: 1 UID: 0 PID: 28842 Comm: v4l_id Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 v4l2_open+0x395/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:444 chrdev_open+0x4cd/0x5e0 fs/char_dev.c:411 do_dentry_open+0x785/0x14e0 fs/open.c:947 vfs_open+0x3b/0x340 fs/open.c:1079 do_open fs/namei.c:4699 [inline] path_openat+0x2e08/0x3860 fs/namei.c:4858 do_file_open+0x23e/0x4a0 fs/namei.c:4887 do_sys_openat2+0x113/0x200 fs/open.c:1364 do_sys_open fs/open.c:1370 [inline] __do_sys_openat fs/open.c:1386 [inline] __se_sys_openat fs/open.c:1381 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1381 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5fdc8a7407 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:00007ffe15b22d00 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f5fdcf74880 RCX: 00007f5fdc8a7407 RDX: 0000000000000000 RSI: 00007ffe15b24f1a RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffe15b22f50 R14: 00007f5fdd079000 R15: 00005637fe70f4d8 Allocated by task 19219: 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:5415 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] em28xx_v4l2_init+0x10b/0x2eb0 drivers/media/usb/em28xx/em28xx-video.c:2707 em28xx_init_extension+0x120/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1248 process_one_work kernel/workqueue.c:3302 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 19219: 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:2689 [inline] slab_free mm/slub.c:6246 [inline] kfree+0x1c5/0x640 mm/slub.c:6561 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2287 [inline] kref_put include/linux/kref.h:65 [inline] em28xx_v4l2_init+0x1685/0x2eb0 drivers/media/usb/em28xx/em28xx-video.c:3078 em28xx_init_extension+0x120/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1248 process_one_work kernel/workqueue.c:3302 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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 ffff88807ebbc000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 2144 bytes inside of freed 8192-byte region [ffff88807ebbc000, ffff88807ebbe000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7ebb8 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 ffff88813fe1a280 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813fe1a280 dead000000000100 dead000000000122 head: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000 head: 00fff00000000003 fffffffffffffe01 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 28772, tgid 28770 (syz.1.6103), ts 1326757918356, free_ts 1326657578724 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1858 prep_new_page mm/page_alloc.c:1866 [inline] get_page_from_freelist+0x24ba/0x2540 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5226 alloc_slab_page mm/slub.c:3278 [inline] allocate_slab+0x77/0x660 mm/slub.c:3467 new_slab mm/slub.c:3525 [inline] refill_objects+0x339/0x3d0 mm/slub.c:7251 refill_sheaf mm/slub.c:2816 [inline] __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4651 alloc_from_pcs mm/slub.c:4749 [inline] slab_alloc_node mm/slub.c:4883 [inline] __kmalloc_cache_noprof+0x392/0x660 mm/slub.c:5410 kmalloc_noprof include/linux/slab.h:950 [inline] audit_log_d_path+0xb8/0x1a0 kernel/audit.c:2198 audit_log_d_path_exe+0x42/0x70 kernel/audit.c:2414 audit_log_task+0x2c3/0x3d0 kernel/auditsc.c:2904 audit_seccomp+0x85/0x190 kernel/auditsc.c:2951 seccomp_log kernel/seccomp.c:1048 [inline] __seccomp_filter+0xd48/0x1ef0 kernel/seccomp.c:1344 syscall_trace_enter include/linux/entry-common.h:103 [inline] syscall_enter_from_user_mode_work include/linux/entry-common.h:147 [inline] syscall_enter_from_user_mode include/linux/entry-common.h:178 [inline] do_syscall_64+0xf9/0xf80 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 5607 tgid 5607 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1402 [inline] __free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943 __folio_put+0x4a2/0x580 mm/swap.c:112 folio_put include/linux/mm.h:2090 [inline] put_page include/linux/mm.h:2159 [inline] put_netmem include/net/netmem.h:409 [inline] skb_page_unref include/linux/skbuff_ref.h:43 [inline] __skb_frag_unref include/linux/skbuff_ref.h:56 [inline] skb_release_data+0x544/0xa60 net/core/skbuff.c:1108 skb_release_all net/core/skbuff.c:1189 [inline] __kfree_skb+0x5d/0x210 net/core/skbuff.c:1203 tcp_clean_rtx_queue net/ipv4/tcp_input.c:3698 [inline] tcp_ack+0x284f/0x7e00 net/ipv4/tcp_input.c:4370 tcp_rcv_established+0x1484/0x2800 net/ipv4/tcp_input.c:6556 tcp_v4_do_rcv+0x964/0x13c0 net/ipv4/tcp_ipv4.c:1852 tcp_v4_rcv+0x2681/0x2ff0 net/ipv4/tcp_ipv4.c:2246 ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:207 ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:241 NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318 dst_input include/net/dst.h:480 [inline] ip_sublist_rcv_finish+0x1f0/0x240 net/ipv4/ip_input.c:623 ip_list_rcv_finish net/ipv4/ip_input.c:675 [inline] ip_sublist_rcv+0x761/0xa70 net/ipv4/ip_input.c:683 ip_list_rcv+0x3f1/0x450 net/ipv4/ip_input.c:717 __netif_receive_skb_list_ptype net/core/dev.c:6245 [inline] __netif_receive_skb_list_core+0x7e5/0x810 net/core/dev.c:6292 __netif_receive_skb_list net/core/dev.c:6344 [inline] netif_receive_skb_list_internal+0x995/0xcf0 net/core/dev.c:6435 Memory state around the buggy address: ffff88807ebbc700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807ebbc780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88807ebbc800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807ebbc880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88807ebbc900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================