==================================================================
BUG: KASAN: use-after-free in inet_twsk_kill+0x358/0x3c0 net/ipv4/inet_timewait_sock.c:46
Read of size 8 at addr ffff88801f0684c0 by task syz-executor.0/6761

CPU: 1 PID: 6761 Comm: syz-executor.0 Not tainted 5.17.0-rc1-next-20220127-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0xa5/0x3e0 mm/kasan/report.c:255
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 inet_twsk_kill+0x358/0x3c0 net/ipv4/inet_timewait_sock.c:46
 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421
 expire_timers kernel/time/timer.c:1466 [inline]
 __run_timers.part.0+0x67c/0xa30 kernel/time/timer.c:1734
 __run_timers kernel/time/timer.c:1715 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:check_kcov_mode+0x2e/0x40 kernel/kcov.c:177
Code: 05 8a 7e 89 c2 81 e2 00 01 00 00 a9 00 01 ff 00 74 10 31 c0 85 d2 74 15 8b 96 ac 15 00 00 85 d2 74 0b 8b 86 88 15 00 00 39 f8 <0f> 94 c0 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 31 c0 65 8b
RSP: 0018:ffffc90002f5fa00 EFLAGS: 00000293
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff8880363fd7c0
RDX: 0000000000000000 RSI: ffff8880363fd7c0 RDI: 0000000000000003
RBP: ffff88801acd1490 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff81d6dec8 R11: 0000000000000000 R12: 0000000000000001
R13: ffffffff81d6de75 R14: ffffc90002f5fc40 R15: 0000000000000000
 write_comp_data kernel/kcov.c:221 [inline]
 __sanitizer_cov_trace_const_cmp1+0x22/0x80 kernel/kcov.c:273
 rcu_read_lock include/linux/rcupdate.h:695 [inline]
 dput+0x88/0xbd0 fs/dcache.c:899
 path_put fs/namei.c:557 [inline]
 terminate_walk+0x19b/0x5c0 fs/namei.c:672
 path_openat+0x1683/0x2940 fs/namei.c:3610
 do_filp_open+0x1aa/0x400 fs/namei.c:3636
 do_sys_openat2+0x16d/0x4d0 fs/open.c:1214
 do_sys_open fs/open.c:1230 [inline]
 __do_sys_openat fs/open.c:1246 [inline]
 __se_sys_openat fs/open.c:1241 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1241
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f34abb00059
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f34aa433168 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f34abc13100 RCX: 00007f34abb00059
RDX: 0000000000000000 RSI: 0000000020000340 RDI: ffffffffffffff9c
RBP: 00007f34abb5a08d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffa6011a9f R14: 00007f34aa433300 R15: 0000000000022000
 </TASK>

Allocated by task 3635:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:436 [inline]
 __kasan_slab_alloc+0x90/0xc0 mm/kasan/common.c:469
 kasan_slab_alloc include/linux/kasan.h:260 [inline]
 slab_post_alloc_hook mm/slab.h:732 [inline]
 slab_alloc_node mm/slub.c:3230 [inline]
 slab_alloc mm/slub.c:3238 [inline]
 kmem_cache_alloc+0x202/0x3a0 mm/slub.c:3243
 kmem_cache_zalloc include/linux/slab.h:705 [inline]
 net_alloc net/core/net_namespace.c:407 [inline]
 copy_net_ns+0x125/0x760 net/core/net_namespace.c:462
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x445/0x920 kernel/fork.c:3048
 __do_sys_unshare kernel/fork.c:3119 [inline]
 __se_sys_unshare kernel/fork.c:3117 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3117
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff88801f068000
 which belongs to the cache net_namespace of size 6528
The buggy address is located 1216 bytes inside of
 6528-byte region [ffff88801f068000, ffff88801f069980)
The buggy address belongs to the page:
page:ffffea00007c1a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88801f068000 pfn:0x1f068
head:ffffea00007c1a00 order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff888022c020c1
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888011a59000
raw: ffff88801f068000 0000000080040002 00000001ffffffff ffff888022c020c1
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3635, ts 208080632611, free_ts 208077957442
 prep_new_page mm/page_alloc.c:2434 [inline]
 get_page_from_freelist+0xa72/0x2f40 mm/page_alloc.c:4165
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5381
 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2271
 alloc_slab_page mm/slub.c:1799 [inline]
 allocate_slab mm/slub.c:1944 [inline]
 new_slab+0x28d/0x380 mm/slub.c:2004
 ___slab_alloc+0x6be/0xd60 mm/slub.c:3018
 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3105
 slab_alloc_node mm/slub.c:3196 [inline]
 slab_alloc mm/slub.c:3238 [inline]
 kmem_cache_alloc+0x35c/0x3a0 mm/slub.c:3243
 kmem_cache_zalloc include/linux/slab.h:705 [inline]
 net_alloc net/core/net_namespace.c:407 [inline]
 copy_net_ns+0x125/0x760 net/core/net_namespace.c:462
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x445/0x920 kernel/fork.c:3048
 __do_sys_unshare kernel/fork.c:3119 [inline]
 __se_sys_unshare kernel/fork.c:3117 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3117
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1352 [inline]
 free_pcp_prepare+0x414/0xb60 mm/page_alloc.c:1404
 free_unref_page_prepare mm/page_alloc.c:3325 [inline]
 free_unref_page+0x19/0x690 mm/page_alloc.c:3404
 skb_free_head net/core/skbuff.c:655 [inline]
 skb_release_data+0x718/0x870 net/core/skbuff.c:677
 skb_release_all net/core/skbuff.c:742 [inline]
 __kfree_skb net/core/skbuff.c:756 [inline]
 consume_skb net/core/skbuff.c:914 [inline]
 consume_skb+0xc2/0x160 net/core/skbuff.c:908
 skb_free_datagram+0x1b/0x1f0 net/core/datagram.c:325
 netlink_recvmsg+0x636/0xea0 net/netlink/af_netlink.c:1998
 sock_recvmsg_nosec net/socket.c:948 [inline]
 sock_recvmsg net/socket.c:966 [inline]
 sock_recvmsg net/socket.c:962 [inline]
 ____sys_recvmsg+0x2c4/0x600 net/socket.c:2632
 ___sys_recvmsg+0x127/0x200 net/socket.c:2674
 __sys_recvmsg+0xe2/0x1a0 net/socket.c:2704
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Memory state around the buggy address:
 ffff88801f068380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801f068400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801f068480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff88801f068500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801f068580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	05 8a 7e 89 c2       	add    $0xc2897e8a,%eax
   5:	81 e2 00 01 00 00    	and    $0x100,%edx
   b:	a9 00 01 ff 00       	test   $0xff0100,%eax
  10:	74 10                	je     0x22
  12:	31 c0                	xor    %eax,%eax
  14:	85 d2                	test   %edx,%edx
  16:	74 15                	je     0x2d
  18:	8b 96 ac 15 00 00    	mov    0x15ac(%rsi),%edx
  1e:	85 d2                	test   %edx,%edx
  20:	74 0b                	je     0x2d
  22:	8b 86 88 15 00 00    	mov    0x1588(%rsi),%eax
  28:	39 f8                	cmp    %edi,%eax
* 2a:	0f 94 c0             	sete   %al <-- trapping instruction
  2d:	c3                   	retq
  2e:	66 66 2e 0f 1f 84 00 	data16 nopw %cs:0x0(%rax,%rax,1)
  35:	00 00 00 00
  39:	0f 1f 00             	nopl   (%rax)
  3c:	31 c0                	xor    %eax,%eax
  3e:	65                   	gs
  3f:	8b                   	.byte 0x8b