==================================================================
BUG: KASAN: use-after-free in tcp_retransmit_timer+0x6ee/0x2890 net/ipv4/tcp_timer.c:515
Read of size 8 at addr ffff888020d50258 by task dhcpcd/3174

CPU: 0 PID: 3174 Comm: dhcpcd Not tainted 5.15.111-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description+0x63/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0x16b/0x1c0 mm/kasan/report.c:451
 tcp_retransmit_timer+0x6ee/0x2890 net/ipv4/tcp_timer.c:515
 tcp_write_timer_handler+0x1f7/0x9c0 net/ipv4/tcp_timer.c:626
 tcp_write_timer+0x12e/0x280 net/ipv4/tcp_timer.c:646
 call_timer_fn+0x16d/0x560 kernel/time/timer.c:1421
 expire_timers kernel/time/timer.c:1466 [inline]
 __run_timers+0x67c/0x890 kernel/time/timer.c:1737
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1750
 __do_softirq+0x3b3/0x93a kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu+0x155/0x240 kernel/softirq.c:636
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648
 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1096
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:85 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x77/0x290 mm/kasan/generic.c:189
Code: 03 49 bb 01 00 00 00 00 fc ff df 4f 8d 34 1a 4c 89 f5 4c 29 cd 48 83 fd 10 7f 26 48 85 ed 0f 84 3a 01 00 00 49 f7 d2 49 01 da <41> 80 39 00 0f 85 c4 01 00 00 49 ff c1 49 ff c2 75 ee e9 1d 01 00
RSP: 0018:ffffc900031bf858 EFLAGS: 00000286
RAX: 0000000000000001 RBX: 1ffff92000637f20 RCX: ffffffff81bef9ed
RDX: 0000000000000001 RSI: 0000000000000028 RDI: ffffc900031bf900
RBP: 0000000000000005 R08: dffffc0000000000 R09: fffff52000637f21
R10: fffffffffffffffc R11: dffffc0000000001 R12: 0000000000012cc0
R13: 1ffff92000637f1c R14: fffff52000637f25 R15: 1ffff92000637f18
 memset+0x1f/0x40 mm/kasan/shadow.c:44
 __alloc_pages+0xbd/0x700 mm/page_alloc.c:5389
 alloc_slab_page mm/slub.c:1775 [inline]
 allocate_slab mm/slub.c:1912 [inline]
 new_slab+0xbb/0x4b0 mm/slub.c:1975
 ___slab_alloc+0x6f6/0xe10 mm/slub.c:3008
 __slab_alloc mm/slub.c:3095 [inline]
 slab_alloc_node mm/slub.c:3186 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc+0x18e/0x280 mm/slub.c:3233
 vm_area_alloc+0x20/0xe0 kernel/fork.c:349
 mmap_region+0xad4/0x1670 mm/mmap.c:1771
 do_mmap+0x78d/0xe00 mm/mmap.c:1575
 vm_mmap_pgoff+0x1ca/0x2d0 mm/util.c:551
 ksys_mmap_pgoff+0x13e/0x780 mm/mmap.c:1624
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f9e19f187e9
Code: 89 e0 5b 5d 41 5c c3 41 89 ca 41 f7 c1 ff 0f 00 00 74 10 48 8b 05 2f 36 0d 00 64 c7 00 16 00 00 00 eb 1b b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 10 48 8b 15 10 36 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffebe261d98 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007ffebe2620b4 RCX: 00007f9e19f187e9
RDX: 0000000000000003 RSI: 0000000000009000 RDI: 0000000000000000
RBP: 00007ffebe262138 R08: 00000000ffffffff R09: 0000000000000000
R10: 0000000000020022 R11: 0000000000000246 R12: 0000000000009000
R13: 00007ffebe262310 R14: 0000000000000002 R15: 00007ffebe262138
 </TASK>

Allocated by task 3530:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0x8e/0xc0 mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x53/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3220 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 net_alloc net/core/net_namespace.c:405 [inline]
 copy_net_ns+0x143/0x5d0 net/core/net_namespace.c:460
 create_new_namespaces+0x425/0x7a0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x11e/0x170 kernel/nsproxy.c:226
 ksys_unshare+0x580/0xb20 kernel/fork.c:3094
 __do_sys_unshare kernel/fork.c:3168 [inline]
 __se_sys_unshare kernel/fork.c:3166 [inline]
 __x64_sys_unshare+0x34/0x40 kernel/fork.c:3166
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

The buggy address belongs to the object at ffff888020d50000
 which belongs to the cache net_namespace of size 6464
The buggy address is located 600 bytes inside of
 6464-byte region [ffff888020d50000, ffff888020d51940)
The buggy address belongs to the page:
page:ffffea0000835400 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888020d50000 pfn:0x20d50
head:ffffea0000835400 order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff88801e4cbbc1
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 0000000100000001 ffff888011dc63c0
raw: ffff888020d50000 0000000080040000 00000001ffffffff ffff88801e4cbbc1
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 3530, ts 89618345854, free_ts 89617354123
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x322a/0x33c0 mm/page_alloc.c:4159
 __alloc_pages+0x272/0x700 mm/page_alloc.c:5421
 alloc_slab_page mm/slub.c:1775 [inline]
 allocate_slab mm/slub.c:1912 [inline]
 new_slab+0xbb/0x4b0 mm/slub.c:1975
 ___slab_alloc+0x6f6/0xe10 mm/slub.c:3008
 __slab_alloc mm/slub.c:3095 [inline]
 slab_alloc_node mm/slub.c:3186 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc+0x18e/0x280 mm/slub.c:3233
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 net_alloc net/core/net_namespace.c:405 [inline]
 copy_net_ns+0x143/0x5d0 net/core/net_namespace.c:460
 create_new_namespaces+0x425/0x7a0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x11e/0x170 kernel/nsproxy.c:226
 ksys_unshare+0x580/0xb20 kernel/fork.c:3094
 __do_sys_unshare kernel/fork.c:3168 [inline]
 __se_sys_unshare kernel/fork.c:3166 [inline]
 __x64_sys_unshare+0x34/0x40 kernel/fork.c:3166
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0xc34/0xcf0 mm/page_alloc.c:3317
 free_unref_page+0x95/0x2d0 mm/page_alloc.c:3396
 free_nonslab_page+0xe4/0x150 mm/slub.c:3535
 kfree+0x1cf/0x270 mm/slub.c:4556
 skb_free_head net/core/skbuff.c:655 [inline]
 skb_release_data+0x73a/0x8a0 net/core/skbuff.c:677
 skb_release_all net/core/skbuff.c:742 [inline]
 __kfree_skb net/core/skbuff.c:756 [inline]
 consume_skb+0xa3/0x140 net/core/skbuff.c:914
 skb_free_datagram+0x24/0xe0 net/core/datagram.c:325
 netlink_recvmsg+0x5ef/0x1190 net/netlink/af_netlink.c:2001
 ____sys_recvmsg+0x286/0x530
 ___sys_recvmsg+0x1ec/0x690 net/socket.c:2673
 __sys_recvmsg net/socket.c:2703 [inline]
 __do_sys_recvmsg net/socket.c:2713 [inline]
 __se_sys_recvmsg net/socket.c:2710 [inline]
 __x64_sys_recvmsg+0x1dc/0x2b0 net/socket.c:2710
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

Memory state around the buggy address:
 ffff888020d50100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888020d50180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888020d50200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff888020d50280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888020d50300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	49 bb 01 00 00 00 00 	movabs $0xdffffc0000000001,%r11
   7:	fc ff df
   a:	4f 8d 34 1a          	lea    (%r10,%r11,1),%r14
   e:	4c 89 f5             	mov    %r14,%rbp
  11:	4c 29 cd             	sub    %r9,%rbp
  14:	48 83 fd 10          	cmp    $0x10,%rbp
  18:	7f 26                	jg     0x40
  1a:	48 85 ed             	test   %rbp,%rbp
  1d:	0f 84 3a 01 00 00    	je     0x15d
  23:	49 f7 d2             	not    %r10
  26:	49 01 da             	add    %rbx,%r10
* 29:	41 80 39 00          	cmpb   $0x0,(%r9) <-- trapping instruction
  2d:	0f 85 c4 01 00 00    	jne    0x1f7
  33:	49 ff c1             	inc    %r9
  36:	49 ff c2             	inc    %r10
  39:	75 ee                	jne    0x29
  3b:	e9                   	.byte 0xe9
  3c:	1d                   	.byte 0x1d
  3d:	01 00                	add    %eax,(%rax)