==================================================================
BUG: KASAN: use-after-free in tcp_probe_timer net/ipv4/tcp_timer.c:378 [inline]
BUG: KASAN: use-after-free in tcp_write_timer_handler net/ipv4/tcp_timer.c:624 [inline]
BUG: KASAN: use-after-free in tcp_write_timer_handler+0x998/0x9f0 net/ipv4/tcp_timer.c:594
Read of size 1 at addr ffff88801d250825 by task syz-fuzzer/3626

CPU: 0 PID: 3626 Comm: syz-fuzzer Not tainted 6.0.0-syzkaller-00372-ga5088ee7251e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:317 [inline]
 print_report.cold+0x2ba/0x6e9 mm/kasan/report.c:433
 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495
 tcp_probe_timer net/ipv4/tcp_timer.c:378 [inline]
 tcp_write_timer_handler net/ipv4/tcp_timer.c:624 [inline]
 tcp_write_timer_handler+0x998/0x9f0 net/ipv4/tcp_timer.c:594
 tcp_write_timer+0xa2/0x2b0 net/ipv4/tcp_timer.c:637
 call_timer_fn+0x1a0/0x6b0 kernel/time/timer.c:1474
 expire_timers kernel/time/timer.c:1519 [inline]
 __run_timers.part.0+0x674/0xa80 kernel/time/timer.c:1790
 __run_timers kernel/time/timer.c:1768 [inline]
 run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1803
 __do_softirq+0x1d3/0x9c6 kernel/softirq.c:571
 invoke_softirq kernel/softirq.c:445 [inline]
 __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1106
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:write_comp_data+0x3c/0x90 kernel/kcov.c:229
Code: 01 00 00 49 89 f8 65 48 8b 14 25 80 6f 02 00 a9 00 01 ff 00 74 0e 85 f6 74 59 8b 82 bc 15 00 00 85 c0 74 4f 8b 82 98 15 00 00 <83> f8 03 75 44 48 8b 82 a0 15 00 00 8b 92 9c 15 00 00 48 8b 38 48
RSP: 0000:ffffc900030b7eb0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81367270
RDX: ffff88807bc72180 RSI: 0000000000000000 RDI: 0000000000000007
RBP: 0000000000000004 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffffc900030b7f58
R13: 000000c01131af08 R14: ffff888076c12250 R15: ffff88801af96840
 __pkru_allows_pkey arch/x86/include/asm/pgtable.h:1384 [inline]
 arch_vma_access_permitted arch/x86/include/asm/mmu_context.h:216 [inline]
 arch_vma_access_permitted arch/x86/include/asm/mmu_context.h:207 [inline]
 access_error arch/x86/mm/fault.c:1106 [inline]
 do_user_addr_fault+0xc20/0x1210 arch/x86/mm/fault.c:1379
 handle_page_fault arch/x86/mm/fault.c:1488 [inline]
 exc_page_fault+0x94/0x170 arch/x86/mm/fault.c:1544
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570
RIP: 0033:0x41e5db
Code: 0f b6 11 44 89 c1 45 89 d5 41 d3 ea 41 0f ba e2 04 0f 83 ec 00 00 00 48 89 44 24 58 41 0f a3 cd 0f 83 87 00 00 00 4e 8d 14 20 <4d> 8b 12 66 90 4d 85 d2 74 79 4d 89 d5 4d 29 e2 4c 39 d2 77 6e 89
RSP: 002b:000000c0005cfe80 EFLAGS: 00010203
RAX: 0000000000000008 RBX: 000000c000041698 RCX: 0000000000000001
RDX: 0000000000000030 RSI: 0000000000203004 RDI: 0000000000c04620
RBP: 000000c0005cff08 R08: 0000000000000001 R09: 00007f3cd3f11d78
R10: 000000c01131af08 R11: 00007f3cd4078fff R12: 000000c01131af00
R13: 00000000000000f2 R14: 000000c00776a4e0 R15: 0000000001142f60
 </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:437 [inline]
 __kasan_slab_alloc+0x85/0xb0 mm/kasan/common.c:470
 kasan_slab_alloc include/linux/kasan.h:224 [inline]
 slab_post_alloc_hook mm/slab.h:727 [inline]
 slab_alloc mm/slab.c:3294 [inline]
 __kmem_cache_alloc_lru mm/slab.c:3471 [inline]
 kmem_cache_alloc+0x214/0x520 mm/slab.c:3491
 kmem_cache_zalloc include/linux/slab.h:723 [inline]
 net_alloc net/core/net_namespace.c:403 [inline]
 copy_net_ns+0x125/0x760 net/core/net_namespace.c:458
 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:3181
 __do_sys_unshare kernel/fork.c:3252 [inline]
 __se_sys_unshare kernel/fork.c:3250 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3250
 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+0x63/0xcd

Freed by task 3853:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track+0x21/0x30 mm/kasan/common.c:45
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
 ____kasan_slab_free mm/kasan/common.c:367 [inline]
 ____kasan_slab_free+0x13d/0x1a0 mm/kasan/common.c:329
 kasan_slab_free include/linux/kasan.h:200 [inline]
 __cache_free mm/slab.c:3418 [inline]
 kmem_cache_free.part.0+0x10f/0x2e0 mm/slab.c:3725
 net_free net/core/net_namespace.c:432 [inline]
 net_free net/core/net_namespace.c:428 [inline]
 cleanup_net+0x8ba/0xb00 net/core/net_namespace.c:615
 process_one_work+0x991/0x1610 kernel/workqueue.c:2289
 worker_thread+0x665/0x1080 kernel/workqueue.c:2436
 kthread+0x2e4/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

The buggy address belongs to the object at ffff88801d250180
 which belongs to the cache net_namespace of size 6784
The buggy address is located 1701 bytes inside of
 6784-byte region [ffff88801d250180, ffff88801d251c00)

The buggy address belongs to the physical page:
page:ffffea0000749400 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1d250
head:ffffea0000749400 order:1 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea0000ce6508 ffffea00007c0908 ffff88801201d500
raw: 0000000000000000 ffff88801d250180 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0x2420c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_COMP|__GFP_THISNODE), pid 3635, tgid 3635 (syz-executor.3), ts 174495189013, free_ts 83628045809
 prep_new_page mm/page_alloc.c:2532 [inline]
 get_page_from_freelist+0x109b/0x2ce0 mm/page_alloc.c:4283
 __alloc_pages+0x1c7/0x510 mm/page_alloc.c:5549
 __alloc_pages_node include/linux/gfp.h:243 [inline]
 kmem_getpages mm/slab.c:1363 [inline]
 cache_grow_begin+0x75/0x360 mm/slab.c:2569
 cache_alloc_refill+0x27f/0x380 mm/slab.c:2942
 ____cache_alloc mm/slab.c:3018 [inline]
 ____cache_alloc mm/slab.c:3001 [inline]
 __do_cache_alloc mm/slab.c:3246 [inline]
 slab_alloc mm/slab.c:3287 [inline]
 __kmem_cache_alloc_lru mm/slab.c:3471 [inline]
 kmem_cache_alloc+0x433/0x520 mm/slab.c:3491
 kmem_cache_zalloc include/linux/slab.h:723 [inline]
 net_alloc net/core/net_namespace.c:403 [inline]
 copy_net_ns+0x125/0x760 net/core/net_namespace.c:458
 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:3181
 __do_sys_unshare kernel/fork.c:3252 [inline]
 __se_sys_unshare kernel/fork.c:3250 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3250
 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+0x63/0xcd
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1449 [inline]
 free_pcp_prepare+0x5e4/0xd20 mm/page_alloc.c:1499
 free_unref_page_prepare mm/page_alloc.c:3380 [inline]
 free_unref_page+0x19/0x4d0 mm/page_alloc.c:3476
 slab_destroy mm/slab.c:1615 [inline]
 slabs_destroy+0x89/0xc0 mm/slab.c:1635
 cache_flusharray mm/slab.c:3389 [inline]
 ___cache_free+0x2a8/0x3d0 mm/slab.c:3452
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x4f/0x1b0 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x97/0xb0 mm/kasan/common.c:447
 kasan_slab_alloc include/linux/kasan.h:224 [inline]
 slab_post_alloc_hook mm/slab.h:727 [inline]
 slab_alloc_node mm/slab.c:3232 [inline]
 kmem_cache_alloc_node+0x2f1/0x560 mm/slab.c:3583
 __alloc_skb+0x210/0x2f0 net/core/skbuff.c:422
 alloc_skb_fclone include/linux/skbuff.h:1307 [inline]
 tcp_stream_alloc_skb+0x38/0x580 net/ipv4/tcp.c:861
 tcp_sendmsg_locked+0xc36/0x2f80 net/ipv4/tcp.c:1325
 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1483
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:819
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:734
 sock_write_iter+0x291/0x3d0 net/socket.c:1108
 call_write_iter include/linux/fs.h:2187 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x9e9/0xdd0 fs/read_write.c:584

Memory state around the buggy address:
 ffff88801d250700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801d250780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801d250800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff88801d250880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801d250900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	01 00                	add    %eax,(%rax)
   2:	00 49 89             	add    %cl,-0x77(%rcx)
   5:	f8                   	clc
   6:	65 48 8b 14 25 80 6f 	mov    %gs:0x26f80,%rdx
   d:	02 00
   f:	a9 00 01 ff 00       	test   $0xff0100,%eax
  14:	74 0e                	je     0x24
  16:	85 f6                	test   %esi,%esi
  18:	74 59                	je     0x73
  1a:	8b 82 bc 15 00 00    	mov    0x15bc(%rdx),%eax
  20:	85 c0                	test   %eax,%eax
  22:	74 4f                	je     0x73
  24:	8b 82 98 15 00 00    	mov    0x1598(%rdx),%eax
* 2a:	83 f8 03             	cmp    $0x3,%eax <-- trapping instruction
  2d:	75 44                	jne    0x73
  2f:	48 8b 82 a0 15 00 00 	mov    0x15a0(%rdx),%rax
  36:	8b 92 9c 15 00 00    	mov    0x159c(%rdx),%edx
  3c:	48 8b 38             	mov    (%rax),%rdi
  3f:	48                   	rex.W