==================================================================
BUG: KASAN: use-after-free in tcp_probe_timer net/ipv4/tcp_timer.c:388 [inline]
BUG: KASAN: use-after-free in tcp_write_timer_handler+0x7ef/0x930 net/ipv4/tcp_timer.c:652
Read of size 1 at addr ffff8880183ea385 by task syz-fuzzer/12078

CPU: 1 PID: 12078 Comm: syz-fuzzer Not tainted 6.1.83-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:395
 kasan_report+0x136/0x160 mm/kasan/report.c:495
 tcp_probe_timer net/ipv4/tcp_timer.c:388 [inline]
 tcp_write_timer_handler+0x7ef/0x930 net/ipv4/tcp_timer.c:652
 tcp_write_timer+0x12e/0x280 net/ipv4/tcp_timer.c:665
 call_timer_fn+0x1ad/0x6b0 kernel/time/timer.c:1474
 expire_timers kernel/time/timer.c:1519 [inline]
 __run_timers+0x67c/0x890 kernel/time/timer.c:1790
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1803
 __do_softirq+0x2e9/0xa4c kernel/softirq.c:571
 invoke_softirq kernel/softirq.c:445 [inline]
 __irq_exit_rcu+0x155/0x240 kernel/softirq.c:650
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662
 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1106
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:235 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x4/0x80 kernel/kcov.c:304
Code: 89 f8 89 f6 49 ff c2 4c 89 11 48 c7 44 0a 08 03 00 00 00 48 89 44 0a 10 48 89 74 0a 18 4c 89 44 0a 20 c3 0f 1f 00 4c 8b 04 24 <65> 48 8b 15 e4 e6 77 7e 65 8b 05 e5 e6 77 7e a9 00 01 ff 00 74 10
RSP: 0018:ffffc9000bba7e38 EFLAGS: 00000246
RAX: ffffffff81f07c99 RBX: dffffc0000000000 RCX: ffff888014260000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000bba7f20 R08: ffffffff81f07cb7 R09: ffffed1002edf0fa
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000094
R13: 1ffff92001774fd0 R14: ffff88802724ef01 R15: ffff88802724f010
 fdput include/linux/file.h:45 [inline]
 fdput_pos include/linux/file.h:81 [inline]
 ksys_write+0x247/0x2c0 fs/read_write.c:640
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x40720e
Code: 48 83 ec 38 e8 13 00 00 00 48 83 c4 38 5d c3 cc cc cc cc cc cc cc cc cc cc cc cc cc 49 89 f2 48 89 fa 48 89 ce 48 89 df 0f 05 <48> 3d 01 f0 ff ff 76 15 48 f7 d8 48 89 c1 48 c7 c0 ff ff ff ff 48
RSP: 002b:000000c001387970 EFLAGS: 00000216 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 000000000040720e
RDX: 0000000000000094 RSI: 000000c001104800 RDI: 0000000000000001
RBP: 000000c0013879b0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000216 R12: 000000c001387af0
R13: 0000000000000093 R14: 000000c000457380 R15: 0000000000000094
 </TASK>

Allocated by task 3559:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 __kasan_slab_alloc+0x65/0x70 mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x52/0x3a0 mm/slab.h:737
 slab_alloc_node mm/slub.c:3398 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc+0x10c/0x2d0 mm/slub.c:3422
 kmem_cache_zalloc include/linux/slab.h:682 [inline]
 net_alloc net/core/net_namespace.c:410 [inline]
 copy_net_ns+0x143/0x5d0 net/core/net_namespace.c:465
 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:3203
 __do_sys_unshare kernel/fork.c:3274 [inline]
 __se_sys_unshare kernel/fork.c:3272 [inline]
 __x64_sys_unshare+0x34/0x40 kernel/fork.c:3272
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Last potentially related work creation:
 kasan_save_stack+0x3b/0x60 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xb0/0xc0 mm/kasan/generic.c:486
 insert_work+0x54/0x3d0 kernel/workqueue.c:1361
 __queue_work+0xb4b/0xf90 kernel/workqueue.c:1520
 call_timer_fn+0x1ad/0x6b0 kernel/time/timer.c:1474
 expire_timers kernel/time/timer.c:1514 [inline]
 __run_timers+0x6a8/0x890 kernel/time/timer.c:1790
 __do_softirq+0x2e9/0xa4c kernel/softirq.c:571

Second to last potentially related work creation:
 kasan_save_stack+0x3b/0x60 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xb0/0xc0 mm/kasan/generic.c:486
 insert_work+0x54/0x3d0 kernel/workqueue.c:1361
 __queue_work+0xb4b/0xf90 kernel/workqueue.c:1520
 call_timer_fn+0x1ad/0x6b0 kernel/time/timer.c:1474
 expire_timers kernel/time/timer.c:1514 [inline]
 __run_timers+0x6a8/0x890 kernel/time/timer.c:1790
 __do_softirq+0x2e9/0xa4c kernel/softirq.c:571

The buggy address belongs to the object at ffff8880183e9c40
 which belongs to the cache net_namespace of size 6976
The buggy address is located 1861 bytes inside of
 6976-byte region [ffff8880183e9c40, ffff8880183eb780)

The buggy address belongs to the physical page:
page:ffffea000060fa00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x183e8
head:ffffea000060fa00 order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff88805da20601
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea0001eaa200 dead000000000002 ffff888140009500
raw: 0000000000000000 0000000080040004 00000001ffffffff ffff88805da20601
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 3556, tgid 3556 (syz-executor.0), ts 53686191540, free_ts 29484328424
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2513
 prep_new_page mm/page_alloc.c:2520 [inline]
 get_page_from_freelist+0x31a1/0x3320 mm/page_alloc.c:4279
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5545
 alloc_slab_page+0x6a/0x150 mm/slub.c:1794
 allocate_slab mm/slub.c:1939 [inline]
 new_slab+0x84/0x2d0 mm/slub.c:1992
 ___slab_alloc+0xc20/0x1270 mm/slub.c:3180
 __slab_alloc mm/slub.c:3279 [inline]
 slab_alloc_node mm/slub.c:3364 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc+0x1a5/0x2d0 mm/slub.c:3422
 kmem_cache_zalloc include/linux/slab.h:682 [inline]
 net_alloc net/core/net_namespace.c:410 [inline]
 copy_net_ns+0x143/0x5d0 net/core/net_namespace.c:465
 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:3203
 __do_sys_unshare kernel/fork.c:3274 [inline]
 __se_sys_unshare kernel/fork.c:3272 [inline]
 __x64_sys_unshare+0x34/0x40 kernel/fork.c:3272
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
 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:1440 [inline]
 free_pcp_prepare mm/page_alloc.c:1490 [inline]
 free_unref_page_prepare+0xf63/0x1120 mm/page_alloc.c:3358
 free_unref_page+0x33/0x3e0 mm/page_alloc.c:3453
 free_slab mm/slub.c:2031 [inline]
 discard_slab mm/slub.c:2037 [inline]
 __unfreeze_partials+0x1b7/0x210 mm/slub.c:2586
 put_cpu_partial+0x17b/0x250 mm/slub.c:2662
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x156/0x170 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x1f/0x70 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x52/0x3a0 mm/slab.h:737
 slab_alloc_node mm/slub.c:3398 [inline]
 kmem_cache_alloc_node+0x136/0x310 mm/slub.c:3443
 __alloc_skb+0xde/0x670 net/core/skbuff.c:505
 alloc_skb include/linux/skbuff.h:1276 [inline]
 alloc_skb_with_frags+0xa4/0x740 net/core/skbuff.c:6157
 sock_alloc_send_pskb+0x915/0xa50 net/core/sock.c:2746
 unix_dgram_sendmsg+0x5b1/0x2050 net/unix/af_unix.c:1939
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 sock_write_iter+0x394/0x4e0 net/socket.c:1143
 do_iter_write+0x6e6/0xc50 fs/read_write.c:861
 vfs_writev fs/read_write.c:934 [inline]
 do_writev+0x27b/0x460 fs/read_write.c:977

Memory state around the buggy address:
 ffff8880183ea280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880183ea300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880183ea380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff8880183ea400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880183ea480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	89 f8                	mov    %edi,%eax
   2:	89 f6                	mov    %esi,%esi
   4:	49 ff c2             	inc    %r10
   7:	4c 89 11             	mov    %r10,(%rcx)
   a:	48 c7 44 0a 08 03 00 	movq   $0x3,0x8(%rdx,%rcx,1)
  11:	00 00
  13:	48 89 44 0a 10       	mov    %rax,0x10(%rdx,%rcx,1)
  18:	48 89 74 0a 18       	mov    %rsi,0x18(%rdx,%rcx,1)
  1d:	4c 89 44 0a 20       	mov    %r8,0x20(%rdx,%rcx,1)
  22:	c3                   	ret
  23:	0f 1f 00             	nopl   (%rax)
  26:	4c 8b 04 24          	mov    (%rsp),%r8
* 2a:	65 48 8b 15 e4 e6 77 	mov    %gs:0x7e77e6e4(%rip),%rdx        # 0x7e77e716 <-- trapping instruction
  31:	7e
  32:	65 8b 05 e5 e6 77 7e 	mov    %gs:0x7e77e6e5(%rip),%eax        # 0x7e77e71e
  39:	a9 00 01 ff 00       	test   $0xff0100,%eax
  3e:	74 10                	je     0x50