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BUG: KASAN: slab-use-after-free in xfrm_alloc_spi+0x570/0xf30
Read of size 4 at addr ffff8880266cc544 by task syz.1.3376/20003

CPU: 1 UID: 0 PID: 20003 Comm: syz.1.3376 Not tainted 6.17.0-rc1-syzkaller-00036-gdfc0f6373094 #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_alloc_spi+0x570/0xf30
 pfkey_getspi+0x7a8/0xee0
 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: 0033:0x7f99b758ebe9
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:00007f99b84ab038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f99b77b5fa0 RCX: 00007f99b758ebe9
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000004
RBP: 00007f99b7611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f99b77b6038 R14: 00007f99b77b5fa0 R15: 00007ffd1223b7a8
 </TASK>

Allocated by task 17565:
 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
 rawv6_sendmsg+0xdab/0x1820
 __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 5314:
 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 ffff8880266cc480
 which belongs to the cache xfrm_state of size 928
The buggy address is located 196 bytes inside of
 freed 928-byte region [ffff8880266cc480, ffff8880266cc820)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880266cdf80 pfn:0x266cc
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000240 ffff888104ed4640 ffff88801b30c708 ffff88801b30c708
raw: ffff8880266cdf80 00000000000e0005 00000000f5000000 0000000000000000
head: 00fff00000000240 ffff888104ed4640 ffff88801b30c708 ffff88801b30c708
head: ffff8880266cdf80 00000000000e0005 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea000099b301 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 6012, tgid 6011 (syz.1.27), ts 59385224219, free_ts 59310680243
 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
 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
page last free pid 6005 tgid 6004 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 stack_depot_save_flags+0x436/0x860
 kasan_save_track+0x4f/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_node_track_caller_noprof+0x271/0x4e0
 kmalloc_reserve+0x136/0x290
 pskb_expand_head+0x18e/0x1150
 skb_expand_head+0x1ad/0x390
 ip6_xmit+0x12e2/0x1840
 sctp_v6_xmit+0xa33/0x1300
 sctp_packet_transmit+0x2581/0x2bb0
 sctp_packet_singleton+0x233/0x330
 sctp_outq_flush+0x4f0/0x3140
 sctp_do_sm+0x5332/0x5a20
 sctp_primitive_ASSOCIATE+0x95/0xc0
 sctp_sendmsg_to_asoc+0x102d/0x1810

Memory state around the buggy address:
 ffff8880266cc400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880266cc480: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880266cc500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff8880266cc580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880266cc600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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