==================================================================
BUG: KASAN: use-after-free in tcp_retransmit_timer+0x2f87/0x3400 net/ipv4/tcp_timer.c:509
Read of size 8 at addr ffff8880462c1e40 by task dhcpcd-run-hook/10335

CPU: 1 PID: 10335 Comm: dhcpcd-run-hook Not tainted 6.0.0-rc3-syzkaller-00945-gb502a6fb46d2 #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/0x719 mm/kasan/report.c:433
 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495
 tcp_retransmit_timer+0x2f87/0x3400 net/ipv4/tcp_timer.c:509
 tcp_write_timer_handler net/ipv4/tcp_timer.c:620 [inline]
 tcp_write_timer_handler+0x4de/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:pmd_devmap_trans_unstable include/linux/pgtable.h:1422 [inline]
RIP: 0010:handle_pte_fault mm/memory.c:4880 [inline]
RIP: 0010:__handle_mm_fault+0xbeb/0x39b0 mm/memory.c:5053
Code: e8 9a f4 c5 ff 48 85 db 0f 84 8b 09 00 00 48 bb 00 00 00 00 00 00 00 04 e8 a2 f7 c5 ff 48 21 eb 31 ff 48 89 de e8 75 f4 c5 ff <48> 85 db 74 30 45 31 e4 e9 72 f8 ff ff e8 83 f7 c5 ff 48 89 da 48
RSP: 0000:ffffc9000351fd18 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81b6122b
RDX: ffff8880516b9d80 RSI: 0000000000000000 RDI: 0000000000000007
RBP: 000000001ce07067 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88804b31d9f0
R13: 0000000000000001 R14: ffff88801ce01210 R15: fff0000000000fff
 handle_mm_fault+0x1c8/0x780 mm/memory.c:5151
 do_user_addr_fault+0x475/0x1210 arch/x86/mm/fault.c:1397
 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: 0033:0x7f0ea7d744b0
Code: Unable to access opcode bytes at RIP 0x7f0ea7d74486.
RSP: 002b:00007ffd44993728 EFLAGS: 00010207
RAX: 0000000000000000 RBX: 00007f0ea7f713d8 RCX: 00007f0ea7dd5fc3
RDX: 00005575f33f4910 RSI: 00005575f33f8218 RDI: 00005575f33fb9e0
RBP: 00005575f33f4480 R08: 0000000000000000 R09: 00007f0ea7fa5000
R10: 00007f0ea7c49800 R11: 0000000000000246 R12: 00005575f33f4910
R13: 00005575f33f5ae0 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Allocated by task 6304:
 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+0x90/0xc0 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_node mm/slub.c:3243 [inline]
 slab_alloc mm/slub.c:3251 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3258 [inline]
 kmem_cache_alloc+0x267/0x3b0 mm/slub.c:3268
 kmem_cache_zalloc include/linux/slab.h:723 [inline]
 net_alloc net/core/net_namespace.c:404 [inline]
 copy_net_ns+0x125/0x760 net/core/net_namespace.c:459
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:227
 ksys_unshare+0x445/0x920 kernel/fork.c:3183
 __do_sys_unshare kernel/fork.c:3254 [inline]
 __se_sys_unshare kernel/fork.c:3252 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3252
 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

Last potentially related work creation:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 __kasan_record_aux_stack+0xbe/0xd0 mm/kasan/generic.c:348
 insert_work+0x48/0x350 kernel/workqueue.c:1358
 __queue_work+0x625/0x1210 kernel/workqueue.c:1517
 call_timer_fn+0x1a0/0x6b0 kernel/time/timer.c:1474
 expire_timers kernel/time/timer.c:1514 [inline]
 __run_timers.part.0+0x4a3/0xa80 kernel/time/timer.c:1790
 __run_timers kernel/time/timer.c:1768 [inline]
 run_timer_softirq+0x152/0x1d0 kernel/time/timer.c:1805
 __do_softirq+0x1d3/0x9c6 kernel/softirq.c:571

The buggy address belongs to the object at ffff8880462c1b80
 which belongs to the cache net_namespace of size 6784
The buggy address is located 704 bytes inside of
 6784-byte region [ffff8880462c1b80, ffff8880462c3600)

The buggy address belongs to the physical page:
page:ffffea000118b000 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880462c1b80 pfn:0x462c0
head:ffffea000118b000 order:3 compound_mapcount:0 compound_pincount:0
memcg:ffff88807a1bd4c1
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000001 ffff8880119db3c0
raw: ffff8880462c1b80 0000000080040000 00000001ffffffff ffff88807a1bd4c1
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 3963, tgid 3961 (syz-executor.1), ts 133605682739, free_ts 133587322469
 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:5515
 alloc_pages+0x1a6/0x270 mm/mempolicy.c:2270
 alloc_slab_page mm/slub.c:1824 [inline]
 allocate_slab+0x27e/0x3d0 mm/slub.c:1969
 new_slab mm/slub.c:2029 [inline]
 ___slab_alloc+0x7f1/0xe10 mm/slub.c:3031
 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3118
 slab_alloc_node mm/slub.c:3209 [inline]
 slab_alloc mm/slub.c:3251 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3258 [inline]
 kmem_cache_alloc+0x38c/0x3b0 mm/slub.c:3268
 kmem_cache_zalloc include/linux/slab.h:723 [inline]
 net_alloc net/core/net_namespace.c:404 [inline]
 copy_net_ns+0x125/0x760 net/core/net_namespace.c:459
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 copy_namespaces+0x391/0x480 kernel/nsproxy.c:178
 copy_process+0x305c/0x7090 kernel/fork.c:2259
 kernel_clone+0xe7/0xab0 kernel/fork.c:2673
 __do_sys_clone+0xba/0x100 kernel/fork.c:2807
 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
 __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2548
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0xa2/0xc0 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/slub.c:3243 [inline]
 slab_alloc mm/slub.c:3251 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3258 [inline]
 kmem_cache_alloc+0x267/0x3b0 mm/slub.c:3268
 vm_area_dup+0x88/0x3f0 kernel/fork.c:467
 dup_mmap kernel/fork.c:641 [inline]
 dup_mm+0x5ea/0x13a0 kernel/fork.c:1524
 copy_mm kernel/fork.c:1576 [inline]
 copy_process+0x3cb9/0x7090 kernel/fork.c:2256
 kernel_clone+0xe7/0xab0 kernel/fork.c:2673
 __do_sys_clone+0xba/0x100 kernel/fork.c:2807
 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

Memory state around the buggy address:
 ffff8880462c1d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880462c1d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880462c1e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff8880462c1e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880462c1f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
   0:	e8 9a f4 c5 ff       	callq  0xffc5f49f
   5:	48 85 db             	test   %rbx,%rbx
   8:	0f 84 8b 09 00 00    	je     0x999
   e:	48 bb 00 00 00 00 00 	movabs $0x400000000000000,%rbx
  15:	00 00 04
  18:	e8 a2 f7 c5 ff       	callq  0xffc5f7bf
  1d:	48 21 eb             	and    %rbp,%rbx
  20:	31 ff                	xor    %edi,%edi
  22:	48 89 de             	mov    %rbx,%rsi
  25:	e8 75 f4 c5 ff       	callq  0xffc5f49f
* 2a:	48 85 db             	test   %rbx,%rbx <-- trapping instruction
  2d:	74 30                	je     0x5f
  2f:	45 31 e4             	xor    %r12d,%r12d
  32:	e9 72 f8 ff ff       	jmpq   0xfffff8a9
  37:	e8 83 f7 c5 ff       	callq  0xffc5f7bf
  3c:	48 89 da             	mov    %rbx,%rdx
  3f:	48                   	rex.W