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BUG: KASAN: slab-use-after-free in xfrm_alloc_spi+0x570/0xf30
Read of size 4 at addr ffff888108dd76c4 by task syz.2.4024/19794

CPU: 0 UID: 0 PID: 19794 Comm: syz.2.4024 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_alloc_spi+0x570/0xf30
 xfrm_alloc_userspi+0x70b/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
RIP: 0033:0x7f7c5378ec29
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:00007f7c54651038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f7c539d5fa0 RCX: 00007f7c5378ec29
RDX: 0000000000000000 RSI: 0000200000000580 RDI: 0000000000000004
RBP: 00007f7c53811e41 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7c539d6038 R14: 00007f7c539d5fa0 R15: 00007ffd0234b768
 </TASK>

Allocated by task 19037:
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_noprof+0x1c1/0x3c0
 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
 ___sys_sendmsg+0x21f/0x2a0
 __x64_sys_sendmsg+0x19b/0x260
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 2381:
 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 ffff888108dd7600
 which belongs to the cache xfrm_state of size 928
The buggy address is located 196 bytes inside of
 freed 928-byte region [ffff888108dd7600, ffff888108dd79a0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888108dd7600 pfn:0x108dd4
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x57ff00000000040(head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000040 ffff88801af1da00 dead000000000122 0000000000000000
raw: ffff888108dd7600 00000000800e000b 00000000f5000000 0000000000000000
head: 057ff00000000040 ffff88801af1da00 dead000000000122 0000000000000000
head: ffff888108dd7600 00000000800e000b 00000000f5000000 0000000000000000
head: 057ff00000000002 ffffea0004237501 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 5989, tgid 5988 (syz.1.26), ts 67285287286, free_ts 67226689733
 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 5978 tgid 5978 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 stack_depot_save_flags+0x436/0x860
 kasan_save_track+0x4f/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_node_noprof+0x276/0x4e0
 alloc_slab_obj_exts+0x39/0xa0
 __memcg_slab_post_alloc_hook+0x31e/0x7f0
 kmem_cache_alloc_noprof+0x2bf/0x3c0
 vm_area_dup+0x2b/0x680
 __split_vma+0x1a9/0xa00
 vma_modify+0x13b3/0x1970
 vma_modify_flags+0x1e8/0x230
 mprotect_fixup+0x407/0x9c0
 do_mprotect_pkey+0x8cd/0xce0
 __x64_sys_mprotect+0x80/0x90
 do_syscall_64+0xfa/0x3b0

Memory state around the buggy address:
 ffff888108dd7580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888108dd7600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888108dd7680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888108dd7700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888108dd7780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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