================================================================== 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 ffff888101360730 by task v4l_id/24032 CPU: 0 UID: 0 PID: 24032 Comm: v4l_id Not tainted 6.16.0-rc2-syzkaller-00033-g9962d0433a86 #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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+0xcd/0x680 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+0x225/0x490 drivers/media/v4l2-core/v4l2-dev.c:429 chrdev_open+0x234/0x6a0 fs/char_dev.c:414 do_dentry_open+0x6da/0x13a0 fs/open.c:964 vfs_open+0x82/0x3f0 fs/open.c:1094 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:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1463 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: 0033:0x7fe04c397407 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:00007ffcd357af80 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fe04c2a9880 RCX: 00007fe04c397407 RDX: 0000000000000000 RSI: 00007ffcd357bf22 RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffcd357b1d0 R14: 00007fe04cb2d000 R15: 0000562327b3c4d8 Allocated by task 9277: 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:3321 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5b3/0x6c0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 9277: 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:2381 [inline] slab_free mm/slub.c:4643 [inline] kfree+0x283/0x470 mm/slub.c:4842 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:3321 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5b3/0x6c0 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 ffff888101360000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 1840 bytes inside of freed 8192-byte region [ffff888101360000, ffff888101362000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x101360 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 ffffea00049cc000 0000000000000004 raw: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000 head: 0200000000000040 ffff888100042280 ffffea00049cc000 0000000000000004 head: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000 head: 0200000000000003 ffffea000404d801 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 0x528c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP), pid 5205, tgid 5205 (udevd), ts 2109122090819, free_ts 2108965541953 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704 prep_new_page mm/page_alloc.c:1712 [inline] get_page_from_freelist+0xf98/0x2ce0 mm/page_alloc.c:3669 __alloc_frozen_pages_noprof+0x259/0x21e0 mm/page_alloc.c:4959 alloc_pages_mpol+0xe4/0x410 mm/mempolicy.c:2419 alloc_slab_page mm/slub.c:2451 [inline] allocate_slab mm/slub.c:2619 [inline] new_slab+0x23b/0x330 mm/slub.c:2673 ___slab_alloc+0xda5/0x1940 mm/slub.c:3859 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3949 __slab_alloc_node mm/slub.c:4024 [inline] slab_alloc_node mm/slub.c:4185 [inline] __do_kmalloc_node mm/slub.c:4327 [inline] __kvmalloc_node_noprof+0x1c1/0x5d0 mm/slub.c:5015 evdev_open+0x115/0x690 drivers/input/evdev.c:468 chrdev_open+0x234/0x6a0 fs/char_dev.c:414 do_dentry_open+0x6da/0x13a0 fs/open.c:964 vfs_open+0x82/0x3f0 fs/open.c:1094 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:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1463 page last free pid 2941 tgid 2941 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1248 [inline] __free_frozen_pages+0x78a/0x1040 mm/page_alloc.c:2706 __folio_put+0x1e7/0x2d0 mm/swap.c:112 folio_put include/linux/mm.h:1356 [inline] put_page include/linux/mm.h:1425 [inline] put_netmem net/core/skbuff.c:7375 [inline] skb_page_unref include/linux/skbuff_ref.h:43 [inline] __skb_frag_unref include/linux/skbuff_ref.h:56 [inline] skb_release_data+0x7fb/0x9c0 net/core/skbuff.c:1081 skb_release_all net/core/skbuff.c:1152 [inline] __napi_kfree_skb net/core/skbuff.c:1442 [inline] kfree_skb_napi_cache net/core/skbuff.c:7171 [inline] skb_attempt_defer_free+0x1b9/0x630 net/core/skbuff.c:7193 tcp_eat_recv_skb net/ipv4/tcp.c:1565 [inline] tcp_recvmsg_locked+0x1250/0x2820 net/ipv4/tcp.c:2862 tcp_recvmsg+0x12f/0x680 net/ipv4/tcp.c:2908 inet_recvmsg+0x12a/0x6a0 net/ipv4/af_inet.c:883 sock_recvmsg_nosec net/socket.c:1017 [inline] sock_recvmsg+0x1b2/0x250 net/socket.c:1039 sock_read_iter+0x2b9/0x3b0 net/socket.c:1109 new_sync_read fs/read_write.c:491 [inline] vfs_read+0xa95/0xc60 fs/read_write.c:572 ksys_read+0x1f8/0x250 fs/read_write.c:715 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: ffff888101360600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888101360680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888101360700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888101360780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888101360800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================