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BUG: KASAN: slab-use-after-free in __xfrm_state_lookup+0x6ad/0x8d0
Read of size 2 at addr ffff888036197bc2 by task syz.2.3366/22335

CPU: 0 UID: 0 PID: 22335 Comm: syz.2.3366 Not tainted syzkaller #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:
 <IRQ>
 dump_stack_lvl+0x189/0x250
 print_report+0xca/0x240
 kasan_report+0x118/0x150
 __xfrm_state_lookup+0x6ad/0x8d0
 xfrm_input_state_lookup+0x6e9/0xa60
 xfrm_input+0x425c/0x72c0
 vti_input+0x219/0x330
 tunnel4_rcv+0xdd/0x2d0
 ip_protocol_deliver_rcu+0x2e0/0x440
 ip_local_deliver_finish+0x3bb/0x6f0
 NF_HOOK+0x30c/0x3a0
 NF_HOOK+0x30c/0x3a0
 __netif_receive_skb+0x143/0x380
 process_backlog+0x60e/0x14f0
 __napi_poll+0xc7/0x360
 net_rx_action+0x707/0xe30
 handle_softirqs+0x286/0x870
 do_softirq+0xec/0x180
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x17d/0x1c0
 __dev_queue_xmit+0x1d79/0x3b50
 ip_finish_output2+0xd40/0x1160
 ip_do_fragment+0x87c/0x1770
 ip_output+0x2a1/0x3c0
 __ip_queue_xmit+0x1106/0x1b00
 __tcp_transmit_skb+0x2215/0x3680
 tcp_write_xmit+0x1862/0x67f0
 tcp_sendmsg_locked+0x2b9f/0x5620
 tcp_sendmsg+0x2f/0x50
 __sock_sendmsg+0x19c/0x270
 sock_sendmsg+0x158/0x230
 splice_to_socket+0x8ff/0xf10
 direct_splice_actor+0x101/0x160
 splice_direct_to_actor+0x5a8/0xcc0
 do_splice_direct+0x181/0x270
 do_sendfile+0x4da/0x7e0
 __se_sys_sendfile64+0x13e/0x190
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f979578ec29
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:00007f9796628038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f97959d6180 RCX: 00007f979578ec29
RDX: 0000000000000000 RSI: 000000000000000b RDI: 0000000000000005
RBP: 00007f9795811e41 R08: 0000000000000000 R09: 0000000000000000
R10: 000000007ffff004 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f97959d6218 R14: 00007f97959d6180 R15: 00007ffe5be645d8
 </TASK>

Allocated by task 21148:
 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 14172:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 kmem_cache_free+0x18f/0x400
 xfrm_state_gc_task+0x52d/0x6b0
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30

The buggy address belongs to the object at ffff888036197a80
 which belongs to the cache xfrm_state of size 928
The buggy address is located 322 bytes inside of
 freed 928-byte region [ffff888036197a80, ffff888036197e20)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888036197600 pfn:0x36194
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 ffff88801c3fcb40 dead000000000122 0000000000000000
raw: ffff888036197600 00000000800e000c 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801c3fcb40 dead000000000122 0000000000000000
head: ffff888036197600 00000000800e000c 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000d86501 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 6730, tgid 6729 (syz.3.192), ts 93046628307, free_ts 82639414701
 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/0x370
 ___slab_alloc+0xbeb/0x1420
 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 5893 tgid 5893 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 __put_partials+0x156/0x1a0
 put_cpu_partial+0x17c/0x250
 __slab_free+0x2d5/0x3c0
 qlist_free_all+0x97/0x140
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0
 __alloc_skb+0x112/0x2d0
 inet6_ifmcaddr_notify+0xeb/0x1d0
 __ipv6_dev_mc_dec+0x2dc/0x330
 ipv6_mc_destroy_dev+0x33c/0x5a0
 addrconf_ifdown+0x139e/0x1880
 addrconf_notify+0x1bc/0x1010
 notifier_call_chain+0x1b6/0x3e0
 unregister_netdevice_many_notify+0x14d7/0x1ff0

Memory state around the buggy address:
 ffff888036197a80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888036197b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888036197b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888036197c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888036197c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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