syzbot

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BUG: KASAN: use-after-free in ax25_fillin_cb_from_dev net/ax25/af_ax25.c:468 [inline]
BUG: KASAN: use-after-free in ax25_fillin_cb+0x459/0x640 net/ax25/af_ax25.c:495
Read of size 4 at addr ffff888078a8bb38 by task syz.0.18/4427

CPU: 1 PID: 4427 Comm: syz.0.18 Not tainted 5.15.189-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_fillin_cb_from_dev net/ax25/af_ax25.c:468 [inline]
 ax25_fillin_cb+0x459/0x640 net/ax25/af_ax25.c:495
 ax25_setsockopt+0x8a2/0xa40 net/ax25/af_ax25.c:690
 __sys_setsockopt+0x2bf/0x3d0 net/socket.c:2203
 __do_sys_setsockopt net/socket.c:2214 [inline]
 __se_sys_setsockopt net/socket.c:2211 [inline]
 __x64_sys_setsockopt+0xb1/0xc0 net/socket.c:2211
 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: 0033:0x7f5bac5049a9
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:00007ffcc3e7d868 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f5bac72bfa0 RCX: 00007f5bac5049a9
RDX: 0000000000000019 RSI: 0000000000000101 RDI: 0000000000000007
RBP: 00007f5bac586d69 R08: 0000000000000010 R09: 0000000000000000
R10: 00002000000001c0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5bac72bfa0 R14: 00007f5bac72bfa0 R15: 0000000000000005
 </TASK>

Allocated by task 4424:
 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]
 ax25_dev_device_up+0x50/0x580 net/ax25/ax25_dev.c:55
 ax25_device_event+0x483/0x4f0 net/ax25/af_ax25.c:139
 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

Freed by task 4426:
 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:1705 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1731
 slab_free mm/slub.c:3499 [inline]
 kfree+0xef/0x2a0 mm/slub.c:4559
 ax25_dev_put include/net/ax25.h:302 [inline]
 ax25_release+0x661/0x870 net/ax25/af_ax25.c:1062
 __sock_release net/socket.c:649 [inline]
 sock_close+0xd5/0x240 net/socket.c:1336
 __fput+0x234/0x930 fs/file_table.c:311
 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:181
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff888078a8bb00
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 56 bytes inside of
 192-byte region [ffff888078a8bb00, ffff888078a8bbc0)
The buggy address belongs to the page:
page:ffffea0001e2a2c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78a8b
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 0000000000000000 dead000000000122 ffff888016841a00
raw: 0000000000000000 0000000000100010 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 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 9, ts 80729620903, free_ts 80727431175
 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:5474
 __alloc_pages_node include/linux/gfp.h:570 [inline]
 alloc_slab_page mm/slub.c:1777 [inline]
 allocate_slab mm/slub.c:1912 [inline]
 new_slab+0xb6/0x4b0 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]
 __kmalloc_node+0x200/0x3b0 mm/slub.c:4451
 kmalloc_array_node include/linux/slab.h:697 [inline]
 kcalloc_node include/linux/slab.h:702 [inline]
 memcg_alloc_page_obj_cgroups+0x81/0x120 mm/memcontrol.c:2839
 account_slab_page mm/slab.h:424 [inline]
 allocate_slab mm/slub.c:1928 [inline]
 new_slab+0x100/0x4b0 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+0x195/0x290 mm/slub.c:3233
 __d_alloc+0x2a/0x6f0 fs/dcache.c:1749
 d_alloc fs/dcache.c:1828 [inline]
 d_alloc_parallel+0x7e/0x12d0 fs/dcache.c:2582
 __lookup_slow+0x113/0x3d0 fs/namei.c:1648
 lookup_one_len+0x18e/0x2c0 fs/namei.c:2718
 start_creating+0x184/0x310 fs/debugfs/inode.c:354
 __debugfs_create_file+0x6f/0x510 fs/debugfs/inode.c:399
 ieee80211_sta_debugfs_add+0x267/0x770 net/mac80211/debugfs_sta.c:1023
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
 __vunmap+0x8ab/0xa40 mm/vmalloc.c:2621
 copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:884 [inline]
 get_entries net/ipv6/netfilter/ip6_tables.c:1041 [inline]
 do_ip6t_get_ctl+0xe1a/0x1090 net/ipv6/netfilter/ip6_tables.c:1679
 nf_getsockopt+0x25e/0x280 net/netfilter/nf_sockopt.c:116
 ipv6_getsockopt+0x442/0x2000 net/ipv6/ipv6_sockglue.c:1492
 tcp_getsockopt+0x1e3/0x2390 net/ipv4/tcp.c:4313
 __sys_getsockopt+0x1b0/0x230 net/socket.c:2247
 __do_sys_getsockopt net/socket.c:2262 [inline]
 __se_sys_getsockopt net/socket.c:2259 [inline]
 __x64_sys_getsockopt+0xb1/0xc0 net/socket.c:2259
 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

Memory state around the buggy address:
 ffff888078a8ba00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888078a8ba80: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
>ffff888078a8bb00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff888078a8bb80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff888078a8bc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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