================================================================== BUG: KASAN: use-after-free in v4l2_fh_init drivers/media/v4l2-core/v4l2-fh.c:25 [inline] BUG: KASAN: use-after-free in v4l2_fh_open+0xc6/0x430 drivers/media/v4l2-core/v4l2-fh.c:63 Read of size 8 at addr ffff88805a644900 by task v4l_id/12612 CPU: 0 PID: 12612 Comm: v4l_id Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 print_address_description+0x60/0x2d0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0xdf/0x130 mm/kasan/report.c:451 v4l2_fh_init drivers/media/v4l2-core/v4l2-fh.c:25 [inline] v4l2_fh_open+0xc6/0x430 drivers/media/v4l2-core/v4l2-fh.c:63 em28xx_v4l2_open+0x152/0x990 drivers/media/usb/em28xx/em28xx-video.c:2163 v4l2_open+0x20b/0x360 drivers/media/v4l2-core/v4l2-dev.c:427 chrdev_open+0x597/0x670 fs/char_dev.c:414 do_dentry_open+0x7ff/0xf80 fs/open.c:826 do_open fs/namei.c:3608 [inline] path_openat+0x2682/0x2f30 fs/namei.c:3742 do_filp_open+0x1b3/0x3e0 fs/namei.c:3769 do_sys_openat2+0x142/0x4a0 fs/open.c:1253 do_sys_open fs/open.c:1269 [inline] __do_sys_openat fs/open.c:1285 [inline] __se_sys_openat fs/open.c:1280 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1280 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f6fda10b407 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:00007ffef28a12f0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f6fda01d880 RCX: 00007f6fda10b407 RDX: 0000000000000000 RSI: 00007ffef28a2f1c RDI: ffffffffffffff9c RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffef28a1540 R14: 00007f6fda899000 R15: 000055e6979754d8 The buggy address belongs to the page: page:ffffea0001699100 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5a644 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000000 ffffea000139f208 ffff8880b91409f0 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 2, migratetype Unmovable, gfp_mask 0x102cc0(GFP_USER|__GFP_NOWARN), pid 4252, ts 631850762069, free_ts 631850767009 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192 __alloc_pages+0x1e1/0x470 mm/page_alloc.c:5487 stack_depot_save+0x342/0x440 lib/stackdepot.c:302 kasan_save_stack mm/kasan/common.c:40 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0xb3/0xd0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3225 [inline] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc+0x100/0x290 mm/slub.c:3238 kmem_cache_zalloc include/linux/slab.h:725 [inline] __kernfs_new_node+0xd6/0x680 fs/kernfs/dir.c:593 kernfs_new_node+0x148/0x250 fs/kernfs/dir.c:669 kernfs_create_link+0xa3/0x200 fs/kernfs/symlink.c:39 sysfs_do_create_link_sd+0x83/0x110 fs/sysfs/symlink.c:44 device_create_sys_dev_entry+0x113/0x170 drivers/base/core.c:3237 device_add+0x986/0xfb0 drivers/base/core.c:3379 cdev_device_add+0x1a4/0x340 fs/char_dev.c:549 evdev_connect+0x34b/0x3f0 drivers/input/evdev.c:1386 input_attach_handler drivers/input/input.c:1046 [inline] input_register_device+0xda7/0x1140 drivers/input/input.c:2429 em28xx_register_snapshot_button+0x2d8/0x460 drivers/media/usb/em28xx/em28xx-input.c:610 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1340 [inline] free_pcp_prepare mm/page_alloc.c:1391 [inline] free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317 free_unref_page+0x94/0x280 mm/page_alloc.c:3396 stack_depot_save+0x418/0x440 lib/stackdepot.c:335 kasan_save_stack mm/kasan/common.c:40 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0xb3/0xd0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3225 [inline] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc+0x100/0x290 mm/slub.c:3238 kmem_cache_zalloc include/linux/slab.h:725 [inline] __kernfs_new_node+0xd6/0x680 fs/kernfs/dir.c:593 kernfs_new_node+0x148/0x250 fs/kernfs/dir.c:669 kernfs_create_link+0xa3/0x200 fs/kernfs/symlink.c:39 sysfs_do_create_link_sd+0x83/0x110 fs/sysfs/symlink.c:44 device_create_sys_dev_entry+0x113/0x170 drivers/base/core.c:3237 device_add+0x986/0xfb0 drivers/base/core.c:3379 cdev_device_add+0x1a4/0x340 fs/char_dev.c:549 evdev_connect+0x34b/0x3f0 drivers/input/evdev.c:1386 input_attach_handler drivers/input/input.c:1046 [inline] input_register_device+0xda7/0x1140 drivers/input/input.c:2429 em28xx_register_snapshot_button+0x2d8/0x460 drivers/media/usb/em28xx/em28xx-input.c:610 Memory state around the buggy address: ffff88805a644800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88805a644880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88805a644900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88805a644980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88805a644a00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ==================================================================