netlink: 4 bytes leftover after parsing attributes in process `syz.4.3166'.
netlink: 13 bytes leftover after parsing attributes in process `syz.4.3166'.
==================================================================
BUG: KASAN: slab-use-after-free in dvb_device_open+0x36a/0x3b0 drivers/media/dvb-core/dvbdev.c:99
Read of size 8 at addr ffff8881404f0218 by task syz.4.3166/23250

CPU: 0 UID: 0 PID: 23250 Comm: syz.4.3166 Not tainted 6.16.0-syzkaller-08685-g260f6f4fda93 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 __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:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 dvb_device_open+0x36a/0x3b0 drivers/media/dvb-core/dvbdev.c:99
 chrdev_open+0x234/0x6a0 fs/char_dev.c:414
 do_dentry_open+0x744/0x1c10 fs/open.c:965
 vfs_open+0x82/0x3f0 fs/open.c:1095
 do_open fs/namei.c:3887 [inline]
 path_openat+0x1de4/0x2cb0 fs/namei.c:4046
 do_filp_open+0x20b/0x470 fs/namei.c:4073
 do_sys_openat2+0x11b/0x1d0 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0x174/0x210 fs/open.c:1461
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f24af98eb69
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f24b075c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f24afbb6080 RCX: 00007f24af98eb69
RDX: 0000000000000001 RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007f24afa11df1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f24afbb6080 R15: 00007ffca3cd2f08
 </TASK>

Allocated by task 21463:
 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
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4364 [inline]
 __kmalloc_noprof+0x223/0x510 mm/slub.c:4376
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kmalloc_array_noprof include/linux/slab.h:948 [inline]
 __list_lru_init+0xe8/0x4c0 mm/list_lru.c:584
 alloc_super+0x8bf/0xbd0 fs/super.c:389
 sget_fc+0x116/0xc20 fs/super.c:761
 vfs_get_super fs/super.c:1320 [inline]
 get_tree_keyed+0x59/0x1d0 fs/super.c:1362
 vfs_get_tree+0x8b/0x340 fs/super.c:1815
 do_new_mount fs/namespace.c:3805 [inline]
 path_mount+0x1482/0x1fd0 fs/namespace.c:4120
 do_mount fs/namespace.c:4133 [inline]
 __do_sys_mount fs/namespace.c:4344 [inline]
 __se_sys_mount fs/namespace.c:4321 [inline]
 __x64_sys_mount+0x28d/0x310 fs/namespace.c:4321
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 19973:
 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:576
 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:233 [inline]
 slab_free_hook mm/slub.c:2416 [inline]
 slab_free mm/slub.c:4679 [inline]
 kfree+0x2b4/0x4d0 mm/slub.c:4878
 list_lru_destroy mm/list_lru.c:607 [inline]
 list_lru_destroy+0x152/0x700 mm/list_lru.c:598
 deactivate_locked_super+0xd5/0x1a0 fs/super.c:483
 deactivate_super fs/super.c:507 [inline]
 deactivate_super+0xde/0x100 fs/super.c:503
 cleanup_mnt+0x225/0x450 fs/namespace.c:1378
 task_work_run+0x150/0x240 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xeb/0x110 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:224 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x3f6/0x490 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8881404f0200
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 24 bytes inside of
 freed 256-byte region [ffff8881404f0200, ffff8881404f0300)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8881404f0200 pfn:0x1404f0
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x57ff00000000240(workingset|head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000240 ffff88801b841b40 ffff888140400708 ffffea0005013590
raw: ffff8881404f0200 000000000010000f 00000000f5000000 0000000000000000
head: 057ff00000000240 ffff88801b841b40 ffff888140400708 ffffea0005013590
head: ffff8881404f0200 000000000010000f 00000000f5000000 0000000000000000
head: 057ff00000000001 ffffea0005013c01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
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 1, tgid 1 (swapper/0), ts 19960061147, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x1321/0x3890 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4959
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2486 [inline]
 allocate_slab mm/slub.c:2654 [inline]
 new_slab+0x247/0x330 mm/slub.c:2708
 ___slab_alloc+0xd1e/0x1780 mm/slub.c:3890
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3980
 __slab_alloc_node mm/slub.c:4055 [inline]
 slab_alloc_node mm/slub.c:4216 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4390
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 bus_add_driver+0x92/0x690 drivers/base/bus.c:662
 driver_register+0x15c/0x4b0 drivers/base/driver.c:249
 vidtv_bridge_init+0x45/0x80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598
 do_one_initcall+0x120/0x6e0 init/main.c:1269
 do_initcall_level init/main.c:1331 [inline]
 do_initcalls init/main.c:1347 [inline]
 do_basic_setup init/main.c:1366 [inline]
 kernel_init_freeable+0x5c2/0x900 init/main.c:1579
 kernel_init+0x1c/0x2b0 init/main.c:1469
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8881404f0100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881404f0180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881404f0200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff8881404f0280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881404f0300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================