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BUG: KASAN: slab-use-after-free in xfrm_state_find+0x2cf2/0x5400
Read of size 1 at addr ffff888113e7c7b0 by task syz.1.4003/18640

CPU: 0 UID: 0 PID: 18640 Comm: syz.1.4003 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_find+0x2cf2/0x5400
 xfrm_resolve_and_create_bundle+0x768/0x2f80
 xfrm_lookup_with_ifid+0x58a/0x1a70
 xfrm_lookup_route+0x3c/0x1c0
 rxrpc_assess_MTU_size+0x3c7/0xa90
 rxrpc_lookup_peer+0x576/0xa60
 rxrpc_do_sendmsg+0xb0a/0x1220
 __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: 0033:0x7fb9e618ebe9
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:00007fb9e6f9c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007fb9e63b5fa0 RCX: 00007fb9e618ebe9
RDX: 0000000000000001 RSI: 0000200000000180 RDI: 000000000000000a
RBP: 00007fb9e6211e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb9e63b6038 R14: 00007fb9e63b5fa0 R15: 00007ffc675be3e8
 </TASK>

Allocated by task 14758:
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_noprof+0x1c1/0x3c0
 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
 udp_sendmsg+0x142e/0x2170
 __sock_sendmsg+0x19c/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

Freed by task 47:
 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 ffff888113e7c480
 which belongs to the cache xfrm_state of size 928
The buggy address is located 816 bytes inside of
 freed 928-byte region [ffff888113e7c480, ffff888113e7c820)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888113e7cd80 pfn:0x113e7c
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000040 ffff88801d3cc3c0 0000000000000000 0000000000000001
raw: ffff888113e7cd80 00000000000e0000 00000000f5000000 0000000000000000
head: 057ff00000000040 ffff88801d3cc3c0 0000000000000000 0000000000000001
head: ffff888113e7cd80 00000000000e0000 00000000f5000000 0000000000000000
head: 057ff00000000002 ffffea00044f9f01 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 8240, tgid 8237 (syz.0.703), ts 92689815416, free_ts 92592318167
 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+0x58a/0x1a70
 xfrm_lookup_route+0x3c/0x1c0
 ip6_sk_dst_lookup_flow+0x790/0x980
 udpv6_sendmsg+0x183b/0x24b0
 __sock_sendmsg+0xe5/0x270
 __sys_sendto+0x3bd/0x520
page last free pid 8226 tgid 8225 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 stack_depot_save_flags+0x436/0x860
 kasan_save_track+0x4f/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_cache_noprof+0x230/0x3d0
 netdevice_event+0x3a1/0x8a0
 notifier_call_chain+0x1b6/0x3e0
 call_netdevice_notifiers+0x88/0xc0
 vlan_dev_open+0x213/0x5e0
 __dev_open+0x470/0x880
 __dev_change_flags+0x1ea/0x6d0
 netif_change_flags+0x88/0x1a0
 dev_change_flags+0x130/0x260
 vlan_device_event+0x1bc2/0x1ef0
 notifier_call_chain+0x1b6/0x3e0
 netif_open+0xfd/0x170

Memory state around the buggy address:
 ffff888113e7c680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888113e7c700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888113e7c780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888113e7c800: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888113e7c880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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