================================================================== 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 ffff888028930860 by task v4l_id/16301 CPU: 0 UID: 0 PID: 16301 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: 0033:0x7f599fca7407 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:00007ffe293337f0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f59a0460880 RCX: 00007f599fca7407 RDX: 0000000000000000 RSI: 00007ffe29334f1a RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffe29333a40 R14: 00007f59a05c7000 R15: 0000562ab5d514d8 Allocated by task 5352: 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:5419 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 5352: 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:6250 [inline] kfree+0x1c5/0x640 mm/slub.c:6565 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 ffff888028930000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 2144 bytes inside of freed 8192-byte region [ffff888028930000, ffff888028932000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x28930 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 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6082, tgid 6082 (syz-executor), ts 118343248479, free_ts 118271432239 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:7255 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] __do_kmalloc_node mm/slub.c:5294 [inline] __kvmalloc_node_noprof+0x657/0x8a0 mm/slub.c:6832 kvmalloc_array_node_noprof include/linux/slab.h:1216 [inline] __ptr_ring_init_queue_alloc_noprof include/linux/ptr_ring.h:481 [inline] ptr_ring_init_noprof include/linux/ptr_ring.h:499 [inline] wg_packet_queue_init+0xbc/0x320 drivers/net/wireguard/queueing.c:32 wg_newlink+0x326/0x670 drivers/net/wireguard/device.c:357 rtnl_newlink_create+0x329/0xb70 net/core/rtnetlink.c:3863 __rtnl_newlink net/core/rtnetlink.c:3994 [inline] rtnl_newlink+0x166a/0x1bb0 net/core/rtnetlink.c:4109 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6995 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x75c/0x8e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:787 [inline] __sock_sendmsg net/socket.c:802 [inline] __sys_sendto+0x672/0x710 net/socket.c:2265 page last free pid 6082 tgid 6082 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 __slab_free+0x274/0x2c0 mm/slub.c:5612 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4569 [inline] slab_alloc_node mm/slub.c:4898 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4905 __kernfs_new_node+0xea/0x970 fs/kernfs/dir.c:664 kernfs_new_node+0x102/0x210 fs/kernfs/dir.c:748 __kernfs_create_file+0x4b/0x2e0 fs/kernfs/file.c:1057 sysfs_add_file_mode_ns+0x238/0x300 fs/sysfs/file.c:313 create_files fs/sysfs/group.c:82 [inline] internal_create_group+0x673/0x1180 fs/sysfs/group.c:189 internal_create_groups fs/sysfs/group.c:229 [inline] sysfs_create_groups+0x59/0x120 fs/sysfs/group.c:255 device_add_groups drivers/base/core.c:2837 [inline] device_add_attrs+0xdd/0x5b0 drivers/base/core.c:2901 device_add+0x496/0xbb0 drivers/base/core.c:3645 netdev_register_kobject+0x178/0x310 net/core/net-sysfs.c:2343 register_netdevice+0x1456/0x1ec0 net/core/dev.c:11420 Memory state around the buggy address: ffff888028930700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888028930780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888028930800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888028930880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888028930900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================