================================================================== 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 ffff88811aa293b8 by task v4l_id/13260 CPU: 1 UID: 0 PID: 13260 Comm: v4l_id Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 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+0x83/0xc0 drivers/media/v4l2-core/v4l2-fh.c:63 em28xx_v4l2_open+0x24e/0x7e0 drivers/media/usb/em28xx/em28xx-video.c:2153 v4l2_open+0x225/0x490 drivers/media/v4l2-core/v4l2-dev.c:429 chrdev_open+0x231/0x6a0 fs/char_dev.c:414 do_dentry_open+0x6da/0x13a0 fs/open.c:965 vfs_open+0x82/0x3f0 fs/open.c:1095 do_open fs/namei.c:3887 [inline] path_openat+0x1de4/0x2cb0 fs/namei.c:4046 do_filp_open+0x20b/0x470 fs/namei.c:4073 do_sys_openat2+0x11b/0x1d0 fs/open.c:1435 do_sys_open fs/open.c:1450 [inline] __do_sys_openat fs/open.c:1466 [inline] __se_sys_openat fs/open.c:1461 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1461 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8670f60407 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:00007fff1bc16430 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f8670e72880 RCX: 00007f8670f60407 RDX: 0000000000000000 RSI: 00007fff1bc16f24 RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007fff1bc16680 R14: 00007f86716f6000 R15: 00005592e78a24d8 Allocated by task 8357: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:405 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [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+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5b6/0x6c0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 8357: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x3e/0x50 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free mm/slub.c:4680 [inline] kfree+0x283/0x470 mm/slub.c:4879 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+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5b6/0x6c0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff88811aa28000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 5048 bytes inside of freed 8192-byte region [ffff88811aa28000, ffff88811aa2a000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11aa28 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0x200000000000040(head|node=0|zone=2) page_type: f5(slab) raw: 0200000000000040 ffff888100042280 ffffea0004693000 dead000000000003 raw: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000 head: 0200000000000040 ffff888100042280 ffffea0004693000 dead000000000003 head: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000 head: 0200000000000003 ffffea00046a8a01 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 2954, tgid 2954 (syz-executor), ts 38900009331, free_ts 36808030189 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851 prep_new_page mm/page_alloc.c:1859 [inline] get_page_from_freelist+0xf98/0x2ce0 mm/page_alloc.c:3858 __alloc_frozen_pages_noprof+0x259/0x21e0 mm/page_alloc.c:5148 alloc_pages_mpol+0xe4/0x410 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:2487 [inline] allocate_slab mm/slub.c:2655 [inline] new_slab+0x247/0x330 mm/slub.c:2709 ___slab_alloc+0xc78/0x1680 mm/slub.c:3891 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3981 __slab_alloc_node mm/slub.c:4056 [inline] slab_alloc_node mm/slub.c:4217 [inline] __kmalloc_cache_noprof+0x209/0x3c0 mm/slub.c:4391 kmalloc_noprof include/linux/slab.h:905 [inline] audit_log_d_path+0xe7/0x200 kernel/audit.c:2149 audit_log_lsm_data+0xf87/0x1fe0 security/lsm_audit.c:199 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+0x168/0x1d0 security/selinux/hooks.c:1681 path_has_perm security/selinux/hooks.c:1719 [inline] selinux_mount+0x384/0x460 security/selinux/hooks.c:2778 security_sb_mount+0x5c/0x90 security/security.c:1570 page last free pid 2943 tgid 2943 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1395 [inline] __free_frozen_pages+0x78a/0xfd0 mm/page_alloc.c:2895 discard_slab mm/slub.c:2753 [inline] __put_partials+0x165/0x1c0 mm/slub.c:3218 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x4e/0x70 mm/kasan/common.c:340 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4180 [inline] slab_alloc_node mm/slub.c:4229 [inline] kmem_cache_alloc_node_noprof+0x14d/0x3a0 mm/slub.c:4281 __alloc_skb+0x2b2/0x380 net/core/skbuff.c:659 alloc_skb_fclone include/linux/skbuff.h:1386 [inline] tcp_stream_alloc_skb+0x34/0x570 net/ipv4/tcp.c:892 tcp_sendmsg_locked+0x12d0/0x4200 net/ipv4/tcp.c:1198 tcp_sendmsg+0x2e/0x50 net/ipv4/tcp.c:1393 inet_sendmsg+0xb9/0x140 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg net/socket.c:729 [inline] sock_write_iter+0x4aa/0x5b0 net/socket.c:1179 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x7d0/0x11d0 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/0x4b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88811aa29280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88811aa29300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88811aa29380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88811aa29400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88811aa29480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================