================================================================== 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 ffff888035874738 by task v4l_id/9734 CPU: 1 UID: 0 PID: 9734 Comm: v4l_id Not tainted 6.12.0-syzkaller-00239-gc6d64479d609 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 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:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 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+0x250/0x7e0 drivers/media/usb/em28xx/em28xx-video.c:2155 v4l2_open+0x222/0x490 drivers/media/v4l2-core/v4l2-dev.c:427 chrdev_open+0x237/0x6a0 fs/char_dev.c:414 do_dentry_open+0x6ca/0x1530 fs/open.c:941 vfs_open+0x82/0x3f0 fs/open.c:1071 do_open fs/namei.c:3828 [inline] path_openat+0x1e6a/0x2d60 fs/namei.c:3987 do_filp_open+0x20c/0x470 fs/namei.c:4014 do_sys_openat2+0x17a/0x1e0 fs/open.c:1398 do_sys_open fs/open.c:1413 [inline] __do_sys_openat fs/open.c:1429 [inline] __se_sys_openat fs/open.c:1424 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1424 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4e241169a4 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:00007ffd2d879e30 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007ffd2d87a048 RCX: 00007f4e241169a4 RDX: 0000000000000000 RSI: 00007ffd2d87af1b RDI: 00000000ffffff9c RBP: 00007ffd2d87af1b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd2d87a060 R14: 000055ebc3390670 R15: 00007f4e24585a80 Allocated by task 5873: 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+0xaa/0xb0 mm/kasan/common.c:394 kmalloc_noprof include/linux/slab.h:878 [inline] kzalloc_noprof include/linux/slab.h:1014 [inline] em28xx_v4l2_init+0x114/0x4050 drivers/media/usb/em28xx/em28xx-video.c:2534 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+0x9c5/0x1ba0 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Freed by task 5873: 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:579 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:2342 [inline] slab_free mm/slub.c:4579 [inline] kfree+0x14f/0x4b0 mm/slub.c:4727 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2120 [inline] kref_put include/linux/kref.h:65 [inline] em28xx_v4l2_init+0x22a4/0x4050 drivers/media/usb/em28xx/em28xx-video.c:2903 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+0x9c5/0x1ba0 kernel/workqueue.c:3229 process_scheduled_works kernel/workqueue.c:3310 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 The buggy address belongs to the object at ffff888035874000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 1848 bytes inside of freed 8192-byte region [ffff888035874000, ffff888035876000) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x35870 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 ffff88801b042280 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080020002 00000001f5000000 0000000000000000 head: 00fff00000000040 ffff88801b042280 dead000000000122 0000000000000000 head: 0000000000000000 0000000080020002 00000001f5000000 0000000000000000 head: 00fff00000000003 ffffea0000d61c01 ffffffffffffffff 0000000000000000 head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000 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 9720, tgid 9719 (syz.2.1085), ts 330818722057, free_ts 266514437873 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1556 prep_new_page mm/page_alloc.c:1564 [inline] get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3474 __alloc_pages_noprof+0x223/0x25a0 mm/page_alloc.c:4751 alloc_pages_mpol_noprof+0x2c9/0x610 mm/mempolicy.c:2265 alloc_slab_page mm/slub.c:2412 [inline] allocate_slab mm/slub.c:2578 [inline] new_slab+0x2c9/0x410 mm/slub.c:2631 ___slab_alloc+0xdac/0x1880 mm/slub.c:3818 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3908 __slab_alloc_node mm/slub.c:3961 [inline] slab_alloc_node mm/slub.c:4122 [inline] __do_kmalloc_node mm/slub.c:4263 [inline] __kmalloc_node_noprof+0x357/0x430 mm/slub.c:4270 __kvmalloc_node_noprof+0x6f/0x1a0 mm/util.c:658 kvmalloc_array_node_noprof include/linux/slab.h:1040 [inline] __ptr_ring_init_queue_alloc_noprof include/linux/ptr_ring.h:471 [inline] ptr_ring_init_noprof include/linux/ptr_ring.h:489 [inline] skb_array_init_noprof include/linux/skb_array.h:182 [inline] pfifo_fast_init+0x125/0x3b0 net/sched/sch_generic.c:871 qdisc_create_dflt+0x101/0x440 net/sched/sch_generic.c:1021 mq_init+0x329/0x470 net/sched/sch_mq.c:90 qdisc_create_dflt+0x101/0x440 net/sched/sch_generic.c:1021 attach_default_qdiscs net/sched/sch_generic.c:1203 [inline] dev_activate+0xaa1/0x12b0 net/sched/sch_generic.c:1257 __dev_open+0x396/0x4e0 net/core/dev.c:1485 __dev_change_flags+0x561/0x720 net/core/dev.c:8845 page last free pid 5200 tgid 5200 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1127 [inline] free_unref_page+0x661/0x1080 mm/page_alloc.c:2657 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:247 [inline] slab_post_alloc_hook mm/slub.c:4085 [inline] slab_alloc_node mm/slub.c:4134 [inline] kmem_cache_alloc_lru_noprof+0x121/0x2f0 mm/slub.c:4153 shmem_alloc_inode+0x25/0x50 mm/shmem.c:4934 alloc_inode+0x5d/0x230 fs/inode.c:336 new_inode_pseudo fs/inode.c:1175 [inline] new_inode+0x22/0x210 fs/inode.c:1194 __shmem_get_inode mm/shmem.c:2854 [inline] shmem_get_inode+0x194/0xe80 mm/shmem.c:2925 shmem_mknod+0x1a8/0x450 mm/shmem.c:3624 lookup_open.isra.0+0x1174/0x14c0 fs/namei.c:3649 open_last_lookups fs/namei.c:3748 [inline] path_openat+0x904/0x2d60 fs/namei.c:3984 do_filp_open+0x20c/0x470 fs/namei.c:4014 do_sys_openat2+0x17a/0x1e0 fs/open.c:1398 do_sys_open fs/open.c:1413 [inline] __do_sys_openat fs/open.c:1429 [inline] __se_sys_openat fs/open.c:1424 [inline] __x64_sys_openat+0x175/0x210 fs/open.c:1424 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 Memory state around the buggy address: ffff888035874600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888035874680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888035874700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888035874780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888035874800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================