================================================================== 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 ffff888109f6c730 by task v4l_id/20404 CPU: 0 UID: 0 PID: 20404 Comm: v4l_id Not tainted 6.15.0-rc4-syzkaller-00104-g588d032e9e56 #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 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:408 [inline] print_report+0xc3/0x670 mm/kasan/report.c:521 kasan_report+0xe0/0x110 mm/kasan/report.c:634 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+0x222/0x490 drivers/media/v4l2-core/v4l2-dev.c:429 chrdev_open+0x231/0x6a0 fs/char_dev.c:414 do_dentry_open+0x6d7/0x13a0 fs/open.c:956 vfs_open+0x82/0x3f0 fs/open.c:1086 do_open fs/namei.c:3880 [inline] path_openat+0x1e5e/0x2d40 fs/namei.c:4039 do_filp_open+0x20b/0x470 fs/namei.c:4066 do_sys_openat2+0x11b/0x1d0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_openat fs/open.c:1460 [inline] __se_sys_openat fs/open.c:1455 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1455 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f41850c59a4 Code: 24 20 48 8d 44 24 30 48 89 44 24 28 64 8b 04 25 18 00 00 00 85 c0 75 2c 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 76 60 48 8b 15 55 a4 0d 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffc86f67020 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007ffc86f67238 RCX: 00007f41850c59a4 RDX: 0000000000000000 RSI: 00007ffc86f67f24 RDI: 00000000ffffff9c RBP: 00007ffc86f67f24 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc86f67250 R14: 0000556d77613670 R15: 00007f4185516a80 Allocated by task 23: 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:377 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:394 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] em28xx_v4l2_init+0x114/0x40c0 drivers/media/usb/em28xx/em28xx-video.c:2532 em28xx_init_extension+0x137/0x200 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:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 23: 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:247 [inline] __kasan_slab_free+0x37/0x50 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2398 [inline] slab_free mm/slub.c:4656 [inline] kfree+0x286/0x470 mm/slub.c:4855 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2118 [inline] kref_put include/linux/kref.h:65 [inline] em28xx_v4l2_init+0x22c5/0x40c0 drivers/media/usb/em28xx/em28xx-video.c:2901 em28xx_init_extension+0x137/0x200 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:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff888109f6c000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 1840 bytes inside of freed 8192-byte region [ffff888109f6c000, ffff888109f6e000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109f68 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 ffffea000405e200 dead000000000002 raw: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000 head: 0200000000000040 ffff888100042280 ffffea000405e200 dead000000000002 head: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000 head: 0200000000000003 ffffea000427da01 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 9, tgid 9 (kworker/0:0), ts 1582675619739, free_ts 1582449048760 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718 prep_new_page mm/page_alloc.c:1726 [inline] get_page_from_freelist+0xfec/0x2d90 mm/page_alloc.c:3688 __alloc_frozen_pages_noprof+0x25c/0x2160 mm/page_alloc.c:4970 alloc_pages_mpol+0xe4/0x410 mm/mempolicy.c:2301 alloc_slab_page mm/slub.c:2468 [inline] allocate_slab mm/slub.c:2632 [inline] new_slab+0x244/0x340 mm/slub.c:2686 ___slab_alloc+0xda5/0x1940 mm/slub.c:3872 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3962 __slab_alloc_node mm/slub.c:4037 [inline] slab_alloc_node mm/slub.c:4198 [inline] __do_kmalloc_node mm/slub.c:4340 [inline] __kmalloc_noprof+0x15b/0x4d0 mm/slub.c:4353 kmalloc_noprof include/linux/slab.h:909 [inline] hcd_buffer_alloc+0x1f5/0x290 drivers/usb/core/buffer.c:134 usb_alloc_coherent+0x5f/0xa0 drivers/usb/core/usb.c:1007 hdpvr_alloc_buffers+0x14c/0x6a0 drivers/media/usb/hdpvr/hdpvr-video.c:157 hdpvr_probe+0x10e5/0x1e40 drivers/media/usb/hdpvr/hdpvr-core.c:350 usb_probe_interface+0x300/0x9c0 drivers/usb/core/driver.c:396 call_driver_probe drivers/base/dd.c:579 [inline] really_probe+0x23e/0xa90 drivers/base/dd.c:657 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:799 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:829 page last free pid 2840 tgid 2840 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0x66c/0xe70 mm/page_alloc.c:2725 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/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:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4161 [inline] slab_alloc_node mm/slub.c:4210 [inline] kmem_cache_alloc_node_noprof+0x14d/0x3a0 mm/slub.c:4262 __alloc_skb+0x2b2/0x380 net/core/skbuff.c:658 alloc_skb include/linux/skbuff.h:1340 [inline] netlink_alloc_large_skb+0x69/0x130 net/netlink/af_netlink.c:1187 netlink_sendmsg+0x6a1/0xdd0 net/netlink/af_netlink.c:1858 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] ____sys_sendmsg+0xa95/0xc70 net/socket.c:2566 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620 __sys_sendmsg+0x16d/0x220 net/socket.c:2652 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888109f6c600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888109f6c680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888109f6c700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888109f6c780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888109f6c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================