syzbot

netlink: 8 bytes leftover after parsing attributes in process `syz.5.835'.
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BUG: KASAN: use-after-free in ax25_unregister_dev_sysctl+0x33/0xa0 net/ax25/sysctl_net_ax25.c:172
Read of size 8 at addr ffff88801abbee18 by task syz.5.835/7742

CPU: 1 PID: 7742 Comm: syz.5.835 Not tainted 5.15.183-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 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
 ax25_unregister_dev_sysctl+0x33/0xa0 net/ax25/sysctl_net_ax25.c:172
 ax25_dev_device_down+0x5b/0x520 net/ax25/ax25_dev.c:101
 ax25_device_event+0x4b4/0x4f0 net/ax25/af_ax25.c:144
 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:2061 [inline]
 call_netdevice_notifiers net/core/dev.c:2075 [inline]
 dev_close_many+0x28d/0x400 net/core/dev.c:1650
 dev_close+0x14c/0x200 net/core/dev.c:1672
 bpq_device_event+0x2f4/0x9c0 drivers/net/hamradio/bpqether.c:548
 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:2061 [inline]
 call_netdevice_notifiers net/core/dev.c:2075 [inline]
 __dev_notify_flags+0x178/0x2d0 net/core/dev.c:-1
 dev_change_flags+0xe3/0x1a0 net/core/dev.c:8929
 dev_ifsioc+0x147/0xe70 net/core/dev_ioctl.c:324
 dev_ioctl+0x55f/0xe50 net/core/dev_ioctl.c:587
 sock_do_ioctl+0x222/0x2f0 net/socket.c:1154
 sock_ioctl+0x4ed/0x6e0 net/socket.c:1257
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 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: 0033:0x7f2a11862969
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:00007f2a0f6ca038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2a11a89fa0 RCX: 00007f2a11862969
RDX: 0000200000000700 RSI: 0000000000008914 RDI: 000000000000000d
RBP: 00007f2a118e4ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2a11a89fa0 R15: 00007ffcc682a548
 </TASK>

Allocated by task 7143:
 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+0xb5/0xf0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:604 [inline]
 kzalloc include/linux/slab.h:735 [inline]
 snd_seq_oss_readq_new+0x4d/0x240 sound/core/seq/oss/seq_oss_readq.c:37
 snd_seq_oss_open+0x725/0xe40 sound/core/seq/oss/seq_oss_init.c:232
 odev_open+0x63/0x90 sound/core/seq/oss/seq_oss.c:128
 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

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+0x10a/0x7c0 kernel/rcu/tree.c:3596
 ip6mr_rules_exit+0x1cd/0x1e0 net/ipv6/ip6mr.c:268
 ip6mr_net_exit+0x6f/0xc0 net/ipv6/ip6mr.c:1345
 ops_exit_list net/core/net_namespace.c:172 [inline]
 cleanup_net+0x6f0/0xb80 net/core/net_namespace.c:635
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

The buggy address belongs to the object at ffff88801abbee00
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 24 bytes inside of
 192-byte region [ffff88801abbee00, ffff88801abbeec0)
The buggy address belongs to the page:
page:ffffea00006aef80 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88801abbe700 pfn:0x1abbe
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea0000897448 ffffea0000697448 ffff888016841a00
raw: ffff88801abbe700 000000000010000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, ts 2355938129, free_ts 0
 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:5466
 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2031
 alloc_slab_page mm/slub.c:1775 [inline]
 allocate_slab mm/slub.c:1912 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1975
 ___slab_alloc+0x81e/0xdf0 mm/slub.c:3008
 __slab_alloc mm/slub.c:3095 [inline]
 slab_alloc_node mm/slub.c:3186 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc_trace+0x1a5/0x2a0 mm/slub.c:3245
 kmalloc include/linux/slab.h:604 [inline]
 kzalloc include/linux/slab.h:735 [inline]
 call_usermodehelper_setup+0x8a/0x260 kernel/umh.c:365
 kobject_uevent_env+0x65e/0x890 lib/kobject_uevent.c:629
 version_sysfs_builtin+0x8b/0xd0 kernel/params.c:878
 param_sysfs_init+0x61/0x70 kernel/params.c:971
 do_one_initcall+0x1ee/0x680 init/main.c:1302
 do_initcall_level+0x137/0x1f0 init/main.c:1375
 do_initcalls+0x4b/0x90 init/main.c:1391
 kernel_init_freeable+0x3ce/0x560 init/main.c:1615
 kernel_init+0x19/0x1b0 init/main.c:1506
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88801abbed00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88801abbed80: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
>ffff88801abbee00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88801abbee80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88801abbef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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