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BUG: KASAN: slab-use-after-free in __xfrm_state_insert+0x8af/0x1450
Read of size 1 at addr ffff88803628ebb0 by task syz.1.3372/17745

CPU: 0 UID: 0 PID: 17745 Comm: syz.1.3372 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_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+0x505/0x830
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f11aa78eba9
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:00007f11a89f6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f11aa9d6180 RCX: 00007f11aa78eba9
RDX: 0000000000000000 RSI: 00002000000001c0 RDI: 0000000000000006
RBP: 00007f11aa811e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f11aa9d6218 R14: 00007f11aa9d6180 R15: 00007fff95c5f648
 </TASK>

Allocated by task 16602:
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_noprof+0x1c1/0x3c0
 xfrm_state_alloc+0x24/0x2f0
 pfkey_add+0x6e4/0x2e00
 pfkey_sendmsg+0xbfe/0x1090
 __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 6514:
 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 ffff88803628e880
 which belongs to the cache xfrm_state of size 928
The buggy address is located 816 bytes inside of
 freed 928-byte region [ffff88803628e880, ffff88803628ec20)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88803628e880 pfn:0x3628c
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 ffff88801abe4780 dead000000000122 0000000000000000
raw: ffff88803628e880 00000000800e000a 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801abe4780 dead000000000122 0000000000000000
head: ffff88803628e880 00000000800e000a 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000d8a301 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 9159, tgid 9151 (syz.0.948), ts 259342395542, free_ts 258548336305
 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_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
page last free pid 9137 tgid 9136 stack trace:
 __free_pages_ok+0xa83/0xbe0
 free_large_kmalloc+0x13a/0x1f0
 skb_release_data+0x62d/0x7c0
 consume_skb+0x9e/0xf0
 sctp_chunk_put+0x17d/0x200
 sctp_datamsg_put+0x409/0x540
 sctp_chunk_free+0x4a/0x60
 __sctp_outq_teardown+0x7ab/0x9a0
 sctp_association_free+0x240/0x7f0
 sctp_do_sm+0x3eba/0x5a20
 sctp_assoc_bh_rcv+0x3f2/0x630
 sctp_backlog_rcv+0x167/0x3f0
 __release_sock+0x297/0x3a0
 release_sock+0x5f/0x1f0
 sctp_sendmsg+0x1b72/0x2810
 __sock_sendmsg+0x19c/0x270

Memory state around the buggy address:
 ffff88803628ea80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803628eb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88803628eb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff88803628ec00: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88803628ec80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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