================================================================== BUG: KASAN: use-after-free in dvb_device_open+0xc5/0x360 drivers/media/dvb-core/dvbdev.c:109 Read of size 8 at addr ffff88802a152e18 by task syz.6.1227/8604 CPU: 1 PID: 8604 Comm: syz.6.1227 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x188/0x250 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 dvb_device_open+0xc5/0x360 drivers/media/dvb-core/dvbdev.c:109 chrdev_open+0x585/0x5f0 fs/char_dev.c:414 do_dentry_open+0x7f7/0xf90 fs/open.c:826 do_open fs/namei.c:3659 [inline] path_openat+0x2718/0x2fb0 fs/namei.c:3793 do_filp_open+0x1df/0x400 fs/namei.c:3820 do_sys_openat2+0x14b/0x500 fs/open.c:1255 do_sys_open fs/open.c:1271 [inline] __do_sys_openat fs/open.c:1287 [inline] __se_sys_openat fs/open.c:1282 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1282 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: 0033:0x7fa2dc5c1d8e Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08 RSP: 002b:00007fa2da858b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fa2da8596c0 RCX: 00007fa2dc5c1d8e RDX: 0000000000040002 RSI: 00007fa2da858c00 RDI: ffffffffffffff9c RBP: 00007fa2da858c00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd R13: 00007fa2dc889038 R14: 00007fa2dc888fa0 R15: 00007ffdf32689b8 Allocated by task 8534: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] ____kasan_kmalloc mm/kasan/common.c:513 [inline] __kasan_kmalloc+0xaf/0xe0 mm/kasan/common.c:522 kmalloc_array include/linux/slab.h:647 [inline] kcalloc include/linux/slab.h:676 [inline] __list_lru_init+0xb6/0xac0 mm/list_lru.c:596 alloc_super+0x787/0x970 fs/super.c:272 sget+0x1ce/0x450 fs/super.c:637 mount_bdev+0xe7/0x3c0 fs/super.c:1384 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611 vfs_get_tree+0x88/0x270 fs/super.c:1541 do_new_mount+0x247/0xa40 fs/namespace.c:3034 do_mount fs/namespace.c:3377 [inline] __do_sys_mount fs/namespace.c:3585 [inline] __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562 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 Freed by task 4192: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1710 [inline] slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736 slab_free mm/slub.c:3504 [inline] kfree+0xef/0x2a0 mm/slub.c:4564 list_lru_destroy+0x3a4/0x430 mm/list_lru.c:633 deactivate_locked_super+0x9f/0xf0 fs/super.c:342 cleanup_mnt+0x426/0x4d0 fs/namespace.c:1148 task_work_run+0x125/0x1a0 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:184 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:217 __syscall_exit_to_user_mode_work kernel/entry/common.c:299 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:310 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Last potentially related work creation: kasan_save_stack+0x35/0x60 mm/kasan/common.c:38 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348 __call_rcu kernel/rcu/tree.c:3011 [inline] call_rcu+0x189/0x900 kernel/rcu/tree.c:3091 fib_create_info+0x190f/0x2450 net/ipv4/fib_semantics.c:1639 fib_table_insert+0xe4/0x1b80 net/ipv4/fib_trie.c:1212 fib_magic+0x2ca/0x3b0 net/ipv4/fib_frontend.c:1113 fib_add_ifaddr+0x135/0x5c0 net/ipv4/fib_frontend.c:1135 fib_netdev_event+0x35c/0x480 net/ipv4/fib_frontend.c:1495 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391 call_netdevice_notifiers_extack net/core/dev.c:2074 [inline] call_netdevice_notifiers net/core/dev.c:2088 [inline] __dev_notify_flags+0x194/0x300 net/core/dev.c:8917 dev_change_flags+0xda/0x1a0 net/core/dev.c:8955 do_setlink+0xca4/0x29d0 net/core/rtnetlink.c:2793 __rtnl_newlink net/core/rtnetlink.c:3464 [inline] rtnl_newlink+0x15bb/0x1920 net/core/rtnetlink.c:3586 rtnetlink_rcv_msg+0x7f1/0xf10 net/core/rtnetlink.c:5698 netlink_rcv_skb+0x1e9/0x430 net/netlink/af_netlink.c:2519 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] netlink_unicast+0x78f/0x940 net/netlink/af_netlink.c:1340 netlink_sendmsg+0x8ba/0xbe0 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:706 [inline] __sock_sendmsg net/socket.c:718 [inline] __sys_sendto+0x46d/0x620 net/socket.c:2073 __do_sys_sendto net/socket.c:2085 [inline] __se_sys_sendto net/socket.c:2081 [inline] __x64_sys_sendto+0xda/0xf0 net/socket.c:2081 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 Second to last potentially related work creation: kasan_save_stack+0x35/0x60 mm/kasan/common.c:38 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348 kvfree_call_rcu+0x105/0x7f0 kernel/rcu/tree.c:3600 drop_sysctl_table+0x359/0x4e0 fs/proc/proc_sysctl.c:1685 drop_sysctl_table+0x348/0x4e0 fs/proc/proc_sysctl.c:1688 unregister_sysctl_table+0x87/0x130 fs/proc/proc_sysctl.c:1723 netfilter_log_sysctl_exit net/netfilter/nf_log.c:514 [inline] nf_log_net_exit+0x5c/0xc0 net/netfilter/nf_log.c:555 ops_exit_list net/core/net_namespace.c:172 [inline] cleanup_net+0x703/0xba0 net/core/net_namespace.c:635 process_one_work+0x867/0xff0 kernel/workqueue.c:2310 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457 kthread+0x42e/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 The buggy address belongs to the object at ffff88802a152e00 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 24 bytes inside of 256-byte region [ffff88802a152e00, ffff88802a152f00) The buggy address belongs to the page: page:ffffea0000a85480 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a152 head:ffffea0000a85480 order:1 compound_mapcount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffffea0001e87380 0000000c0000000c ffff888017841b40 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 2819, ts 21791554651, free_ts 0 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501 alloc_slab_page mm/slub.c:1780 [inline] allocate_slab mm/slub.c:1917 [inline] new_slab+0xc0/0x4b0 mm/slub.c:1980 ___slab_alloc+0x807/0xdd0 mm/slub.c:3013 __slab_alloc mm/slub.c:3100 [inline] slab_alloc_node mm/slub.c:3191 [inline] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc_trace+0xf9/0x290 mm/slub.c:3250 kmalloc include/linux/slab.h:607 [inline] kzalloc include/linux/slab.h:738 [inline] set_kthread_struct kernel/kthread.c:103 [inline] kthread+0x10a/0x520 kernel/kthread.c:296 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 page_owner free stack trace missing Memory state around the buggy address: ffff88802a152d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802a152d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802a152e00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802a152e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802a152f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================