==================================================================
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+0x99c/0x9f0 net/ipv4/tcp_timer.c:594
Read of size 1 at addr ffff88801d183fc5 by task kworker/u4:1/11

CPU: 0 PID: 11 Comm: kworker/u4:1 Not tainted 6.1.0-rc8-syzkaller-00165-ge095493091e8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x15e/0x45d mm/kasan/report.c:395
 kasan_report+0xbf/0x1f0 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+0x99c/0x9f0 net/ipv4/tcp_timer.c:594
 tcp_write_timer+0xa6/0x2b0 net/ipv4/tcp_timer.c:637
 call_timer_fn+0x1da/0x7c0 kernel/time/timer.c:1474
 expire_timers kernel/time/timer.c:1519 [inline]
 __run_timers.part.0+0x6a2/0xaf0 kernel/time/timer.c:1790
 __run_timers kernel/time/timer.c:1768 [inline]
 run_timer_softirq+0xb7/0x1d0 kernel/time/timer.c:1803
 __do_softirq+0x1fb/0xadc kernel/softirq.c:571
 invoke_softirq kernel/softirq.c:445 [inline]
 __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:662
 sysvec_apic_timer_interrupt+0x97/0xc0 arch/x86/kernel/apic/apic.c:1107
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:write_comp_data+0x7/0x90 kernel/kcov.c:230
Code: 81 e2 00 01 ff 00 75 10 65 48 8b 04 25 c0 7f 02 00 48 8b 80 80 15 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 65 8b 05 19 66 82 7e <49> 89 f1 89 c6 49 89 d2 81 e6 00 01 00 00 49 89 f8 65 48 8b 14 25
RSP: 0018:ffffc90000107c80 EFLAGS: 00000246
RAX: 0000000080000000 RBX: 0000000000000400 RCX: ffffffff897c8955
RDX: 0000000000000400 RSI: 00000000000000c0 RDI: 0000000000000004
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: dffffc0000000000 R15: 00000000000000c0
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:405 [inline]
 batadv_nc_worker+0x8a5/0xfa0 net/batman-adv/network-coding.c:719
 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
 worker_thread+0x669/0x1090 kernel/workqueue.c:2436
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>

Allocated by task 3665:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 kasan_set_track+0x25/0x30 mm/kasan/common.c:52
 __kasan_slab_alloc+0x82/0x90 mm/kasan/common.c:325
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slab.h:737 [inline]
 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+0x2b4/0x3d0 mm/slub.c:3422
 kmem_cache_zalloc include/linux/slab.h:679 [inline]
 net_alloc net/core/net_namespace.c:410 [inline]
 copy_net_ns+0x129/0x760 net/core/net_namespace.c:465
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc5/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x449/0x920 kernel/fork.c:3188
 __do_sys_unshare kernel/fork.c:3259 [inline]
 __se_sys_unshare kernel/fork.c:3257 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3257
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Last potentially related work creation:
 kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:481
 insert_work+0x48/0x350 kernel/workqueue.c:1358
 __queue_work+0x693/0x13b0 kernel/workqueue.c:1517
 call_timer_fn+0x1da/0x7c0 kernel/time/timer.c:1474
 expire_timers kernel/time/timer.c:1514 [inline]
 __run_timers.part.0+0x4a3/0xaf0 kernel/time/timer.c:1790
 __run_timers kernel/time/timer.c:1768 [inline]
 run_timer_softirq+0x156/0x1d0 kernel/time/timer.c:1805
 __do_softirq+0x1fb/0xadc kernel/softirq.c:571

The buggy address belongs to the object at ffff88801d183880
 which belongs to the cache net_namespace of size 6976
The buggy address is located 1861 bytes inside of
 6976-byte region [ffff88801d183880, ffff88801d1853c0)

The buggy address belongs to the physical page:
page:ffffea0000746000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1d180
head:ffffea0000746000 order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff88807f2b7e41
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 dead000000000100 dead000000000122 ffff8880121e1500
raw: 0000000000000000 0000000080040004 00000001ffffffff ffff88807f2b7e41
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 3648, tgid 3648 (syz-executor.3), ts 73733839041, free_ts 73729398566
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x10b5/0x2d50 mm/page_alloc.c:4291
 __alloc_pages+0x1cb/0x5b0 mm/page_alloc.c:5558
 alloc_pages+0x1aa/0x270 mm/mempolicy.c:2285
 alloc_slab_page mm/slub.c:1794 [inline]
 allocate_slab+0x25f/0x350 mm/slub.c:1939
 new_slab mm/slub.c:1992 [inline]
 ___slab_alloc+0xa91/0x1400 mm/slub.c:3180
 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3279
 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+0x31a/0x3d0 mm/slub.c:3422
 kmem_cache_zalloc include/linux/slab.h:679 [inline]
 net_alloc net/core/net_namespace.c:410 [inline]
 copy_net_ns+0x129/0x760 net/core/net_namespace.c:465
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc5/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x449/0x920 kernel/fork.c:3188
 __do_sys_unshare kernel/fork.c:3259 [inline]
 __se_sys_unshare kernel/fork.c:3257 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3257
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 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:1459 [inline]
 free_pcp_prepare+0x65c/0xd90 mm/page_alloc.c:1509
 free_unref_page_prepare mm/page_alloc.c:3387 [inline]
 free_unref_page+0x1d/0x4d0 mm/page_alloc.c:3483
 skb_free_head+0xac/0x110 net/core/skbuff.c:760
 skb_release_data+0x5f1/0x870 net/core/skbuff.c:789
 skb_release_all net/core/skbuff.c:854 [inline]
 __kfree_skb net/core/skbuff.c:868 [inline]
 consume_skb net/core/skbuff.c:1033 [inline]
 consume_skb+0xc6/0x160 net/core/skbuff.c:1027
 netlink_recvmsg+0x59c/0xe50 net/netlink/af_netlink.c:1998
 sock_recvmsg_nosec net/socket.c:995 [inline]
 sock_recvmsg net/socket.c:1013 [inline]
 sock_recvmsg net/socket.c:1009 [inline]
 ____sys_recvmsg+0x2c7/0x610 net/socket.c:2701
 ___sys_recvmsg+0xf2/0x180 net/socket.c:2743
 __sys_recvmsg+0xf4/0x1c0 net/socket.c:2773
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff88801d183e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801d183f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801d183f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff88801d184000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801d184080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	81 e2 00 01 ff 00    	and    $0xff0100,%edx
   6:	75 10                	jne    0x18
   8:	65 48 8b 04 25 c0 7f 	mov    %gs:0x27fc0,%rax
   f:	02 00
  11:	48 8b 80 80 15 00 00 	mov    0x1580(%rax),%rax
  18:	c3                   	retq
  19:	66 2e 0f 1f 84 00 00 	nopw   %cs:0x0(%rax,%rax,1)
  20:	00 00 00
  23:	65 8b 05 19 66 82 7e 	mov    %gs:0x7e826619(%rip),%eax        # 0x7e826643
* 2a:	49 89 f1             	mov    %rsi,%r9 <-- trapping instruction
  2d:	89 c6                	mov    %eax,%esi
  2f:	49 89 d2             	mov    %rdx,%r10
  32:	81 e6 00 01 00 00    	and    $0x100,%esi
  38:	49 89 f8             	mov    %rdi,%r8
  3b:	65                   	gs
  3c:	48                   	rex.W
  3d:	8b                   	.byte 0x8b
  3e:	14 25                	adc    $0x25,%al