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BUG: KASAN: slab-use-after-free in __xfrm_state_lookup+0x6ad/0x8d0
Read of size 2 at addr ffff888035ed6e42 by task syz.2.9368/30660

CPU: 1 UID: 0 PID: 30660 Comm: syz.2.9368 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:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_report+0xca/0x240
 kasan_report+0x118/0x150
 __xfrm_state_lookup+0x6ad/0x8d0
 xfrm_state_lookup+0x11e/0x1e0
 vti6_err+0x2f7/0x520
 xfrm6_ipcomp_err+0xc1/0x210
 icmpv6_notify+0x391/0x7e0
 icmpv6_rcv+0x1352/0x1c80
 ip6_protocol_deliver_rcu+0xe0b/0x15c0
 ip6_input_finish+0x191/0x370
 NF_HOOK+0x30c/0x3a0
 ip6_input+0x16a/0x270
 ip6_mc_input+0x5c8/0xaf0
 NF_HOOK+0x30c/0x3a0
 __netif_receive_skb+0xd3/0x380
 netif_receive_skb+0x1cb/0x790
 tun_rx_batched+0x1b9/0x730
 tun_get_user+0x2aa2/0x3e20
 tun_chr_write_iter+0x113/0x200
 vfs_write+0x5c9/0xb30
 ksys_write+0x145/0x250
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f71eab8d69f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48
RSP: 002b:00007f71eb945000 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f71eadb5fa0 RCX: 00007f71eab8d69f
RDX: 000000000000006e RSI: 0000200000001440 RDI: 00000000000000c8
RBP: 00007f71eac11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000006e R11: 0000000000000293 R12: 0000000000000000
R13: 00007f71eadb6038 R14: 00007f71eadb5fa0 R15: 00007ffd92da4988
 </TASK>

Allocated by task 28578:
 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 24:
 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+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30

The buggy address belongs to the object at ffff888035ed6d00
 which belongs to the cache xfrm_state of size 928
The buggy address is located 322 bytes inside of
 freed 928-byte region [ffff888035ed6d00, ffff888035ed70a0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888035ed7180 pfn:0x35ed4
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 ffff88801c70a140 dead000000000122 0000000000000000
raw: ffff888035ed7180 00000000800e0001 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801c70a140 dead000000000122 0000000000000000
head: ffff888035ed7180 00000000800e0001 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000d7b501 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 16941, tgid 16939 (syz.6.3700), ts 347397887524, free_ts 333521424448
 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/0x1410
 kmem_cache_alloc_noprof+0x283/0x3c0
 xfrm_state_alloc+0x24/0x2f0
 xfrm_state_find+0x37d4/0x5400
 xfrm_resolve_and_create_bundle+0x768/0x2f80
 xfrm_lookup_with_ifid+0x2a7/0x1a70
 xfrm_lookup_route+0x3c/0x1c0
 rawv6_sendmsg+0xdab/0x1820
 __sock_sendmsg+0x19c/0x270
 ____sys_sendmsg+0x52d/0x830
 ___sys_sendmsg+0x21f/0x2a0
page last free pid 16289 tgid 16287 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
 __kmalloc_noprof+0x224/0x4f0
 fanotify_handle_event+0x2654/0x3d00
 fsnotify+0x1412/0x1a80
 __fsnotify_parent+0x3fe/0x540
 __kernel_read+0x73b/0x960
 integrity_kernel_read+0x89/0xd0
 ima_calc_file_hash+0x85e/0x16f0
 ima_collect_measurement+0x428/0x8e0
 process_measurement+0x1121/0x1a40

Memory state around the buggy address:
 ffff888035ed6d00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888035ed6d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888035ed6e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888035ed6e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888035ed6f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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