================================================================== BUG: KASAN: slab-use-after-free in v4l2_fh_init drivers/media/v4l2-core/v4l2-fh.c:25 [inline] BUG: KASAN: slab-use-after-free in v4l2_fh_open+0xc7/0x430 drivers/media/v4l2-core/v4l2-fh.c:63 Read of size 8 at addr ffff88804244c738 by task v4l_id/16685 CPU: 0 UID: 0 PID: 16685 Comm: v4l_id Not tainted 6.15.0-rc6-syzkaller-00047-ge9565e23cd89 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xb4/0x290 mm/kasan/report.c:521 kasan_report+0x118/0x150 mm/kasan/report.c:634 v4l2_fh_init drivers/media/v4l2-core/v4l2-fh.c:25 [inline] v4l2_fh_open+0xc7/0x430 drivers/media/v4l2-core/v4l2-fh.c:63 em28xx_v4l2_open+0x157/0x9a0 drivers/media/usb/em28xx/em28xx-video.c:2153 v4l2_open+0x20f/0x360 drivers/media/v4l2-core/v4l2-dev.c:429 chrdev_open+0x4cc/0x5e0 fs/char_dev.c:414 do_dentry_open+0xdf3/0x1970 fs/open.c:956 vfs_open+0x3b/0x340 fs/open.c:1086 do_open fs/namei.c:3880 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4039 do_filp_open+0x1fa/0x410 fs/namei.c:4066 do_sys_openat2+0x121/0x1c0 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+0x138/0x170 fs/open.c:1455 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdb7e2a7407 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:00007ffdadcdb670 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fdb7ea07880 RCX: 00007fdb7e2a7407 RDX: 0000000000000000 RSI: 00007ffdadcdcf18 RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffdadcdb8c0 R14: 00007fdb7eb6e000 R15: 0000564dd5f514d8 Allocated by task 10264: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4358 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] em28xx_v4l2_init+0x10b/0x2e70 drivers/media/usb/em28xx/em28xx-video.c:2532 em28xx_init_extension+0x11d/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1117 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xade/0x17a0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 10264: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2380 [inline] slab_free mm/slub.c:4642 [inline] kfree+0x193/0x440 mm/slub.c:4841 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2118 [inline] kref_put include/linux/kref.h:65 [inline] em28xx_v4l2_init+0x1683/0x2e70 drivers/media/usb/em28xx/em28xx-video.c:2901 em28xx_init_extension+0x11d/0x1c0 drivers/media/usb/em28xx/em28xx-core.c:1117 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xade/0x17a0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/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 ffff88804244c000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 1848 bytes inside of freed 8192-byte region [ffff88804244c000, ffff88804244e000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x42448 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 ffff88801a042280 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801a042280 dead000000000122 0000000000000000 head: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0001091201 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 16642, tgid 16634 (syz.8.10448), ts 2801849788833, free_ts 2800625274232 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1d8/0x230 mm/page_alloc.c:1718 prep_new_page mm/page_alloc.c:1726 [inline] get_page_from_freelist+0x21ce/0x22b0 mm/page_alloc.c:3688 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4970 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2301 alloc_slab_page mm/slub.c:2450 [inline] allocate_slab+0x8a/0x3b0 mm/slub.c:2618 new_slab mm/slub.c:2672 [inline] ___slab_alloc+0xbfc/0x1480 mm/slub.c:3858 __slab_alloc mm/slub.c:3948 [inline] __slab_alloc_node mm/slub.c:4023 [inline] slab_alloc_node mm/slub.c:4184 [inline] __do_kmalloc_node mm/slub.c:4326 [inline] __kvmalloc_node_noprof+0x411/0x5e0 mm/slub.c:5012 snd_pcm_oss_change_params_locked+0x2dfb/0x3f60 sound/core/oss/pcm_oss.c:1068 snd_pcm_oss_change_params sound/core/oss/pcm_oss.c:1105 [inline] snd_pcm_oss_get_active_substream+0x20b/0x280 sound/core/oss/pcm_oss.c:1122 snd_pcm_oss_get_rate sound/core/oss/pcm_oss.c:1778 [inline] snd_pcm_oss_set_rate+0x1bc/0x4e0 sound/core/oss/pcm_oss.c:1770 snd_pcm_oss_ioctl+0xc2e/0xdd0 sound/core/oss/pcm_oss.c:2623 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f page last free pid 16632 tgid 16625 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0xb0e/0xcd0 mm/page_alloc.c:2725 discard_slab mm/slub.c:2716 [inline] __put_partials+0x161/0x1c0 mm/slub.c:3185 put_cpu_partial+0x17c/0x250 mm/slub.c:3260 __slab_free+0x2f7/0x400 mm/slub.c:4512 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4147 [inline] slab_alloc_node mm/slub.c:4196 [inline] __do_kmalloc_node mm/slub.c:4326 [inline] __kmalloc_noprof+0x224/0x4f0 mm/slub.c:4339 kmalloc_noprof include/linux/slab.h:909 [inline] tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_number_perm+0x1e8/0x5a0 security/tomoyo/file.c:723 security_file_ioctl+0xcb/0x2d0 security/security.c:2913 __do_sys_ioctl fs/ioctl.c:900 [inline] __se_sys_ioctl+0x47/0x170 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88804244c600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804244c680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88804244c700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88804244c780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804244c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================