================================================================== BUG: KASAN: slab-use-after-free in v4l2_open+0x334/0x340 drivers/media/v4l2-core/v4l2-dev.c:432 Read of size 4 at addr ffff888026904830 by task v4l_id/5886 CPU: 0 PID: 5886 Comm: v4l_id Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xa8/0x210 mm/kasan/report.c:468 kasan_report+0x117/0x150 mm/kasan/report.c:581 v4l2_open+0x334/0x340 drivers/media/v4l2-core/v4l2-dev.c:432 chrdev_open+0x58c/0x600 fs/char_dev.c:414 do_dentry_open+0x880/0x14b0 fs/open.c:929 do_open fs/namei.c:3683 [inline] path_openat+0x284f/0x3270 fs/namei.c:3844 do_filp_open+0x1f2/0x430 fs/namei.c:3871 do_sys_openat2+0x134/0x1d0 fs/open.c:1422 do_sys_open fs/open.c:1437 [inline] __do_sys_openat fs/open.c:1453 [inline] __se_sys_openat fs/open.c:1448 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1448 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f1f0dca7407 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:00007ffcb7d33b40 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f1f0e365880 RCX: 00007f1f0dca7407 RDX: 0000000000000000 RSI: 00007ffcb7d35f1d RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffcb7d33d90 R14: 00007f1f0e462000 R15: 0000563fd1e354d8 Allocated by task 5844: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384 kmalloc include/linux/slab.h:600 [inline] kzalloc include/linux/slab.h:721 [inline] em28xx_v4l2_init+0xf9/0x2d90 drivers/media/usb/em28xx/em28xx-video.c:2538 em28xx_init_extension+0x11c/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1116 process_one_work kernel/workqueue.c:2657 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 Freed by task 5844: kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1811 [inline] slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837 slab_free mm/slub.c:3830 [inline] __kmem_cache_free+0xba/0x1f0 mm/slub.c:3843 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2118 [inline] kref_put include/linux/kref.h:65 [inline] em28xx_v4l2_init+0x15fb/0x2d90 drivers/media/usb/em28xx/em28xx-video.c:2907 em28xx_init_extension+0x11c/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1116 process_one_work kernel/workqueue.c:2657 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 The buggy address belongs to the object at ffff888026904000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 2096 bytes inside of freed 8192-byte region [ffff888026904000, ffff888026906000) The buggy address belongs to the physical page: page:ffffea00009a4000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x26900 head:ffffea00009a4000 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000840 ffff888017c42280 ffffea00009a6e00 0000000000000006 raw: 0000000000000000 0000000080020002 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5625, tgid 5625 (sshd-session), ts 59795889035, free_ts 59752320095 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1582 prep_new_page mm/page_alloc.c:1589 [inline] get_page_from_freelist+0x2181/0x22a0 mm/page_alloc.c:3221 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4501 alloc_slab_page+0x5d/0x180 mm/slub.c:1881 allocate_slab mm/slub.c:2028 [inline] new_slab+0x87/0x2d0 mm/slub.c:2081 ___slab_alloc+0xc5c/0x12f0 mm/slub.c:3253 __slab_alloc mm/slub.c:3339 [inline] __slab_alloc_node mm/slub.c:3392 [inline] slab_alloc_node mm/slub.c:3485 [inline] __kmem_cache_alloc_node+0x11f/0x250 mm/slub.c:3534 __do_kmalloc_node mm/slab_common.c:1006 [inline] __kmalloc_node_track_caller+0xa4/0x230 mm/slab_common.c:1027 kmalloc_reserve+0x116/0x240 net/core/skbuff.c:584 __alloc_skb+0x138/0x2c0 net/core/skbuff.c:653 alloc_skb include/linux/skbuff.h:1316 [inline] netlink_dump+0x1a4/0xec0 net/netlink/af_netlink.c:2222 netlink_recvmsg+0x693/0xe60 net/netlink/af_netlink.c:1981 sock_recvmsg_nosec net/socket.c:1047 [inline] sock_recvmsg net/socket.c:1069 [inline] ____sys_recvmsg+0x2bd/0x5d0 net/socket.c:2814 ___sys_recvmsg+0x214/0x590 net/socket.c:2856 __sys_recvmsg net/socket.c:2886 [inline] __do_sys_recvmsg net/socket.c:2896 [inline] __se_sys_recvmsg net/socket.c:2893 [inline] __x64_sys_recvmsg+0x21e/0x2f0 net/socket.c:2893 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1182 [inline] free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2459 folio_put include/linux/mm.h:1492 [inline] put_page include/linux/mm.h:1561 [inline] do_exit+0x1a82/0x2530 kernel/exit.c:921 do_group_exit+0x22d/0x2f0 kernel/exit.c:1032 __do_sys_exit_group kernel/exit.c:1043 [inline] __se_sys_exit_group kernel/exit.c:1041 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1041 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 Memory state around the buggy address: ffff888026904700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888026904780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888026904800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888026904880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888026904900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================