================================================================== BUG: KASAN: slab-use-after-free in v4l2_fh_init+0x27d/0x2c0 drivers/media/v4l2-core/v4l2-fh.c:25 Read of size 8 at addr ffff88811b10c738 by task v4l_id/25591 CPU: 1 UID: 0 PID: 25591 Comm: v4l_id Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 v4l2_fh_init+0x27d/0x2c0 drivers/media/v4l2-core/v4l2-fh.c:25 v4l2_fh_open+0x64/0xa0 drivers/media/v4l2-core/v4l2-fh.c:64 em28xx_v4l2_open+0x24e/0x7e0 drivers/media/usb/em28xx/em28xx-video.c:2153 v4l2_open+0x1d2/0x5e0 drivers/media/v4l2-core/v4l2-dev.c:433 chrdev_open+0x234/0x6a0 fs/char_dev.c:414 do_dentry_open+0x723/0x13e0 fs/open.c:962 vfs_open+0x82/0x3f0 fs/open.c:1094 do_open fs/namei.c:4628 [inline] path_openat+0x2078/0x3140 fs/namei.c:4787 do_filp_open+0x20b/0x470 fs/namei.c:4814 do_sys_openat2+0x120/0x260 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1447 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x570 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa85b389407 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:00007fff4bfcdfe0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fa85b29b880 RCX: 00007fa85b389407 RDX: 0000000000000000 RSI: 00007fff4bfcff24 RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007fff4bfce230 R14: 00007fa85bb1f000 R15: 0000561d5ecf84d8 Allocated by task 20683: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:414 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] em28xx_v4l2_init+0x114/0x4080 drivers/media/usb/em28xx/em28xx-video.c:2532 em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1117 request_module_async+0x61/0x70 drivers/media/usb/em28xx/em28xx-cards.c:3457 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x74f/0xa30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Freed by task 20683: kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 kasan_save_track+0x14/0x30 mm/kasan/common.c:77 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x43/0x70 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2540 [inline] slab_free mm/slub.c:6670 [inline] kfree+0x2c8/0x680 mm/slub.c:6878 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2118 [inline] kref_put include/linux/kref.h:65 [inline] em28xx_v4l2_init+0x22b5/0x4080 drivers/media/usb/em28xx/em28xx-video.c:2901 em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1117 request_module_async+0x61/0x70 drivers/media/usb/em28xx/em28xx-cards.c:3457 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x74f/0xa30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 The buggy address belongs to the object at ffff88811b10c000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 1848 bytes inside of freed 8192-byte region [ffff88811b10c000, ffff88811b10e000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11b108 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x200000000000040(head|node=0|zone=2) page_type: f5(slab) raw: 0200000000000040 ffff888100042280 ffffea00051fbe00 dead000000000002 raw: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000 head: 0200000000000040 ffff888100042280 ffffea00051fbe00 dead000000000002 head: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000 head: 0200000000000003 ffffea00046c4201 00000000ffffffff 00000000ffffffff head: 0000000000000000 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 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 2970, tgid 2970 (syz-executor), ts 53295379707, free_ts 52363539437 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1846 prep_new_page mm/page_alloc.c:1854 [inline] get_page_from_freelist+0x1058/0x3cb0 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x259/0x21c0 mm/page_alloc.c:5210 alloc_pages_mpol+0xe4/0x410 mm/mempolicy.c:2486 alloc_slab_page mm/slub.c:3075 [inline] allocate_slab mm/slub.c:3248 [inline] new_slab+0x2c3/0x430 mm/slub.c:3302 ___slab_alloc+0xe20/0x1ca0 mm/slub.c:4656 __slab_alloc.constprop.0+0x63/0x110 mm/slub.c:4779 __slab_alloc_node mm/slub.c:4855 [inline] slab_alloc_node mm/slub.c:5251 [inline] __kmalloc_cache_noprof+0x3d6/0x7e0 mm/slub.c:5771 kmalloc_noprof include/linux/slab.h:957 [inline] audit_log_d_path+0xed/0x200 kernel/audit.c:2193 audit_log_lsm_data+0xacf/0x1fe0 security/lsm_audit.c:212 dump_common_audit_data security/lsm_audit.c:421 [inline] common_lsm_audit+0x238/0x300 security/lsm_audit.c:451 slow_avc_audit+0x186/0x210 security/selinux/avc.c:779 avc_audit security/selinux/include/avc.h:131 [inline] avc_has_perm+0x1b5/0x1f0 security/selinux/avc.c:1198 inode_has_perm+0x166/0x1d0 security/selinux/hooks.c:1687 file_path_has_perm security/selinux/hooks.c:1737 [inline] selinux_file_open+0x39d/0x510 security/selinux/hooks.c:4163 security_file_open+0x34/0x70 security/security.c:2636 page last free pid 2962 tgid 2962 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0x795/0x1010 mm/page_alloc.c:2943 __folio_put+0x1e7/0x2d0 mm/swap.c:112 folio_put include/linux/mm.h:1612 [inline] put_page include/linux/mm.h:1681 [inline] put_netmem+0x28b/0x300 net/core/skbuff.c:7417 skb_page_unref include/linux/skbuff_ref.h:43 [inline] __skb_frag_unref include/linux/skbuff_ref.h:56 [inline] skb_frag_unref include/linux/skbuff_ref.h:71 [inline] __pskb_trim_head+0x5c7/0x7b0 net/ipv4/tcp_output.c:1867 tcp_trim_head+0x85/0x5f0 net/ipv4/tcp_output.c:1894 tcp_tso_acked net/ipv4/tcp_input.c:3364 [inline] tcp_clean_rtx_queue net/ipv4/tcp_input.c:3430 [inline] tcp_ack+0x1cfa/0x5f40 net/ipv4/tcp_input.c:4119 tcp_rcv_established+0x10b6/0x36d0 net/ipv4/tcp_input.c:6374 tcp_v4_do_rcv+0x5dc/0xaa0 net/ipv4/tcp_ipv4.c:1881 sk_backlog_rcv include/net/sock.h:1177 [inline] __release_sock+0x361/0x450 net/core/sock.c:3213 release_sock+0x5a/0x220 net/core/sock.c:3795 tcp_sendmsg+0x38/0x50 net/ipv4/tcp.c:1413 inet_sendmsg+0xb9/0x140 net/ipv4/af_inet.c:859 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] sock_write_iter+0x509/0x610 net/socket.c:1195 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x7d3/0x11d0 fs/read_write.c:686 ksys_write+0x1f8/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x570 arch/x86/entry/syscall_64.c:94 Memory state around the buggy address: ffff88811b10c600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88811b10c680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88811b10c700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88811b10c780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88811b10c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================