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BUG: KASAN: slab-use-after-free in __xfrm_state_insert+0x8af/0x1450
Read of size 1 at addr ffff88803945b930 by task syz.2.2968/14356

CPU: 0 UID: 0 PID: 14356 Comm: syz.2.2968 Not tainted 6.16.0-rc7-syzkaller-01993-ge3f96b3556e4 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_report+0xca/0x230
 kasan_report+0x118/0x150
 __xfrm_state_insert+0x8af/0x1450
 xfrm_state_insert+0x54/0x60
 ipcomp6_init_state+0x655/0x900
 __xfrm_init_state+0xa76/0x13f0
 xfrm_init_state+0x18/0xa0
 pfkey_add+0x1d38/0x2e00
 pfkey_sendmsg+0xbfe/0x1090
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x52d/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __sys_sendmmsg+0x227/0x430
 __x64_sys_sendmmsg+0xa0/0xc0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa24cd8e9a9
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:00007fa24dc09038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007fa24cfb5fa0 RCX: 00007fa24cd8e9a9
RDX: 000000000400008a RSI: 0000200000000180 RDI: 0000000000000004
RBP: 00007fa24ce10d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fa24cfb5fa0 R15: 00007fffe981f738
 </TASK>

Allocated by task 12795:
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_noprof+0x1c1/0x3c0
 xfrm_state_alloc+0x24/0x2f0
 __find_acq_core+0x8a7/0x1c00
 xfrm_find_acq+0x78/0xa0
 xfrm_alloc_userspi+0x6b3/0xc90
 xfrm_user_rcv_msg+0x7a3/0xab0
 netlink_rcv_skb+0x208/0x470
 xfrm_netlink_rcv+0x79/0x90
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 10:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x62/0x70
 kmem_cache_free+0x18f/0x400
 xfrm_state_gc_task+0x518/0x6a0
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30

The buggy address belongs to the object at ffff88803945b600
 which belongs to the cache xfrm_state of size 928
The buggy address is located 816 bytes inside of
 freed 928-byte region [ffff88803945b600, ffff88803945b9a0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88803945b600 pfn:0x39458
head: order:2 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 ffff888104a908c0 dead000000000122 0000000000000000
raw: ffff88803945b600 00000000800e000a 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff888104a908c0 dead000000000122 0000000000000000
head: ffff88803945b600 00000000800e000a 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000e51601 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5933, tgid 5932 (syz.1.16), ts 57371591496, free_ts 57325617680
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x21e4/0x22c0
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 allocate_slab+0x8a/0x3b0
 ___slab_alloc+0xbfc/0x1480
 kmem_cache_alloc_noprof+0x283/0x3c0
 xfrm_state_alloc+0x24/0x2f0
 xfrm_add_sa+0x17d1/0x4070
 xfrm_user_rcv_msg+0x7a3/0xab0
 netlink_rcv_skb+0x208/0x470
 xfrm_netlink_rcv+0x79/0x90
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270
 ____sys_sendmsg+0x505/0x830
page last free pid 5928 tgid 5927 stack trace:
 __free_frozen_pages+0xc71/0xe70
 stack_depot_save_flags+0x445/0x900
 ref_tracker_free+0xfe/0x7d0
 __netdev_adjacent_dev_remove+0x382/0x5d0
 __netdev_upper_dev_unlink+0x1ec/0x7c0
 netdev_upper_dev_unlink+0x91/0xd0
 batadv_hardif_disable_interface+0x977/0xf20
 batadv_meshif_slave_del+0x75/0xf0
 do_set_master+0x312/0x6d0
 do_setlink+0xcf0/0x41c0
 rtnl_newlink+0x149f/0x1c70
 rtnetlink_rcv_msg+0x7cf/0xb70
 netlink_rcv_skb+0x208/0x470
 netlink_unicast+0x82f/0x9e0
 netlink_sendmsg+0x805/0xb30
 __sock_sendmsg+0x21c/0x270

Memory state around the buggy address:
 ffff88803945b800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803945b880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88803945b900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff88803945b980: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88803945ba00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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