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BUG: KASAN: slab-use-after-free in __xfrm_state_delete+0x696/0xca0
Write of size 8 at addr ffff888031fe8db0 by task syz.4.2290/13195

CPU: 0 UID: 0 PID: 13195 Comm: syz.4.2290 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:
 <IRQ>
 dump_stack_lvl+0x189/0x250
 print_report+0xca/0x240
 kasan_report+0x118/0x150
 __xfrm_state_delete+0x696/0xca0
 xfrm_timer_handler+0x18f/0xa00
 __hrtimer_run_queues+0x52c/0xc60
 hrtimer_run_softirq+0x187/0x2b0
 handle_softirqs+0x286/0x870
 __irq_exit_rcu+0xca/0x1f0
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:smp_call_function_many_cond+0xd44/0x12d0
Code: 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 61 5e 0b 00 eb 38 f3 90 42 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 <74> 1e e8 45 5e 0b 00 eb e4 44 89 e1 80 e1 07 80 c1 03 38 c1 7c e2
RSP: 0018:ffffc9000318f340 EFLAGS: 00000202
RAX: 0000000000000000 RBX: 1ffff11026cc7f61 RCX: ffff888031bc1cc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000318f4c0 R08: ffffffff8fa38337 R09: 1ffffffff1f47066
R10: dffffc0000000000 R11: fffffbfff1f47067 R12: ffff88813663fb08
R13: dffffc0000000000 R14: ffff88804b03b1c0 R15: 0000000000000001
 on_each_cpu_cond_mask+0x3f/0x80
 flush_tlb_mm_range+0x6b1/0x12d0
 tlb_flush_mmu+0x1a7/0x680
 tlb_finish_mmu+0xc3/0x1d0
 free_ldt_pgtables+0x17b/0x320
 exit_mmap+0x17c/0xb50
 __mmput+0x118/0x420
 exit_mm+0x1da/0x2c0
 do_exit+0x648/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1286/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff25cf8ebe9
Code: Unable to access opcode bytes at 0x7ff25cf8ebbf.
RSP: 002b:00007ff25dd0e0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007ff25d1b5fa8 RCX: 00007ff25cf8ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff25d1b5fa8
RBP: 00007ff25d1b5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff25d1b6038 R14: 00007ffe7fedb970 R15: 00007ffe7fedba58
 </TASK>

Allocated by task 12497:
 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 7771:
 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 ffff888031fe8d80
 which belongs to the cache xfrm_state of size 928
The buggy address is located 48 bytes inside of
 freed 928-byte region [ffff888031fe8d80, ffff888031fe9120)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x31fe8
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 ffff88801abf3640 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800e000e 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801abf3640 dead000000000122 0000000000000000
head: 0000000000000000 00000000800e000e 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000c7fa01 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 9135, tgid 9134 (syz.0.1040), ts 99434239336, free_ts 99252585805
 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
 __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
page last free pid 9110 tgid 9105 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 free_large_kmalloc+0x13a/0x1f0
 free_netdev+0x3e2/0x700
 netdev_run_todo+0xd0c/0xea0
 tun_chr_close+0x13c/0x1c0
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 do_exit+0x6b5/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1286/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888031fe8c80: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888031fe8d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888031fe8d80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888031fe8e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888031fe8e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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