================================================================== 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 ffff888112324788 by task v4l_id/6397 CPU: 0 UID: 0 PID: 6397 Comm: v4l_id Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x156/0x4c9 mm/kasan/report.c:482 kasan_report+0xdf/0x1e0 mm/kasan/report.c:595 v4l2_fh_init+0x27d/0x2c0 drivers/media/v4l2-core/v4l2-fh.c:25 v4l2_fh_open+0x64/0xa0 drivers/media/v4l2-core/v4l2-fh.c:64 em28xx_v4l2_open+0x11e/0x570 drivers/media/usb/em28xx/em28xx-video.c:2153 v4l2_open+0x1d2/0x490 drivers/media/v4l2-core/v4l2-dev.c:433 chrdev_open+0x234/0x6a0 fs/char_dev.c:411 do_dentry_open+0x68b/0x14b0 fs/open.c:949 vfs_open+0x82/0x3f0 fs/open.c:1081 do_open fs/namei.c:4677 [inline] path_openat+0x208c/0x31a0 fs/namei.c:4836 do_file_open+0x20e/0x430 fs/namei.c:4865 do_sys_openat2+0x10d/0x1e0 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x12d/0x210 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0x7b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fac95412407 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:00007ffdaabc8250 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fac95324880 RCX: 00007fac95412407 RDX: 0000000000000000 RSI: 00007ffdaabc9f24 RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffdaabc84a0 R14: 00007fac95ba8000 R15: 000056177ae4e4d8 Allocated by task 28: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:415 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] em28xx_v4l2_init.cold+0x94/0x3503 drivers/media/usb/em28xx/em28xx-video.c:2532 em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1117 request_module_async+0x61/0x80 drivers/media/usb/em28xx/em28xx-cards.c:3457 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276 process_scheduled_works kernel/workqueue.c:3359 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x6c3/0xcb0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 28: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x43/0x70 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2685 [inline] slab_free mm/slub.c:6165 [inline] kfree+0x1dc/0x640 mm/slub.c:6483 kref_put.isra.0+0x56/0x90 include/linux/kref.h:65 em28xx_v4l2_init.cold+0x280/0x3503 drivers/media/usb/em28xx/em28xx-video.c:2901 em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1117 request_module_async+0x61/0x80 drivers/media/usb/em28xx/em28xx-cards.c:3457 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276 process_scheduled_works kernel/workqueue.c:3359 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x6c3/0xcb0 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 ffff888112324000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 1928 bytes inside of freed 8192-byte region [ffff888112324000, ffff888112326000) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x112320 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 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000 head: 0200000000000040 ffff888100042280 dead000000000100 dead000000000122 head: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000 head: 0200000000000003 ffffea000448c801 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 23, tgid 23 (kworker/1:0), ts 94712657985, free_ts 86408957125 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889 prep_new_page mm/page_alloc.c:1897 [inline] get_page_from_freelist+0xf10/0x39f0 mm/page_alloc.c:3962 __alloc_frozen_pages_noprof+0x273/0x2860 mm/page_alloc.c:5250 alloc_slab_page mm/slub.c:3292 [inline] allocate_slab mm/slub.c:3481 [inline] new_slab+0xa6/0x6c0 mm/slub.c:3539 refill_objects+0x26b/0x400 mm/slub.c:7175 refill_sheaf mm/slub.c:2812 [inline] __pcs_replace_empty_main+0x1ab/0x660 mm/slub.c:4615 alloc_from_pcs mm/slub.c:4717 [inline] slab_alloc_node mm/slub.c:4851 [inline] __kmalloc_cache_noprof+0x52c/0x6b0 mm/slub.c:5375 kmalloc_noprof include/linux/slab.h:950 [inline] audit_log_d_path+0xed/0x210 kernel/audit.c:2196 audit_log_lsm_data+0xff3/0x1fa0 security/lsm_audit.c:212 dump_common_audit_data security/lsm_audit.c:421 [inline] common_lsm_audit+0x229/0x2b0 security/lsm_audit.c:451 slow_avc_audit+0x186/0x210 security/selinux/avc.c:779 avc_audit security/selinux/include/avc.h:131 [inline] avc_has_perm+0x1a6/0x1e0 security/selinux/avc.c:1198 selinux_kernel_load_from_file+0x2e0/0x410 security/selinux/hooks.c:4295 selinux_kernel_read_file+0x83/0x130 security/selinux/hooks.c:4309 security_kernel_read_file+0x48/0xa0 security/security.c:2875 kernel_read_file+0x47b/0x9a0 fs/kernel_read_file.c:72 page last free pid 5230 tgid 5230 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0x7b1/0xfb0 mm/page_alloc.c:2978 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x4e/0x70 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4538 [inline] slab_alloc_node mm/slub.c:4866 [inline] __kmalloc_cache_noprof+0x254/0x6b0 mm/slub.c:5375 kmalloc_noprof include/linux/slab.h:950 [inline] inode_doinit_use_xattr+0x54/0x330 security/selinux/hooks.c:1377 inode_doinit_with_dentry+0x10e6/0x1320 security/selinux/hooks.c:1571 selinux_d_instantiate+0x26/0x40 security/selinux/hooks.c:6550 security_d_instantiate+0x62/0xc0 security/security.c:3602 d_splice_alias_ops+0xd7/0x1320 fs/dcache.c:3074 kernfs_iop_lookup+0x23f/0x2d0 fs/kernfs/dir.c:1256 __lookup_slow+0x251/0x460 fs/namei.c:1916 lookup_slow+0x50/0x70 fs/namei.c:1933 walk_component fs/namei.c:2279 [inline] link_path_walk+0x13c0/0x1b30 fs/namei.c:2653 path_lookupat+0x74/0xc40 fs/namei.c:2809 filename_lookup+0x202/0x590 fs/namei.c:2839 Memory state around the buggy address: ffff888112324680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888112324700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888112324780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888112324800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888112324880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================