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BUG: KASAN: use-after-free in tcp_probe_timer net/ipv4/tcp_timer.c:360 [inline]
BUG: KASAN: use-after-free in tcp_write_timer_handler+0x8c6/0x8d0 net/ipv4/tcp_timer.c:596
Read of size 4 at addr ffff88806aa54750 by task kworker/u4:12/10471

CPU: 1 PID: 10471 Comm: kworker/u4:12 Not tainted 5.3.0-rc6+ #179
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351
 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482
 kasan_report+0x12/0x17 mm/kasan/common.c:618
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131
 tcp_probe_timer net/ipv4/tcp_timer.c:360 [inline]
 tcp_write_timer_handler+0x8c6/0x8d0 net/ipv4/tcp_timer.c:596
 tcp_write_timer+0xa8/0x1e0 net/ipv4/tcp_timer.c:612
 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1322
 expire_timers kernel/time/timer.c:1366 [inline]
 __run_timers kernel/time/timer.c:1685 [inline]
 __run_timers kernel/time/timer.c:1653 [inline]
 run_timer_softirq+0x697/0x17a0 kernel/time/timer.c:1698
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x19b/0x1e0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:537 [inline]
 smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1133
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
 </IRQ>
RIP: 0010:___might_sleep+0x6/0x280 kernel/sched/core.c:6566
Code: 1f 44 00 00 5d c3 0f 0b 48 c7 c7 48 f4 d2 88 e8 c0 ad 5d 00 eb dd 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 57 <41> 56 41 55 41 89 f5 41 54 49 89 fc 53 89 d3 e8 66 22 10 00 85 c0
RSP: 0018:ffff888066e7fb58 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff88806658e140 RBX: 000000000000ffff RCX: 0000000000000ae6
RDX: 0000000000000000 RSI: 000000000000010b RDI: ffffffff882f7020
RBP: ffff888066e7fb60 R08: ffff88806658e140 R09: fffffbfff134afe0
R10: fffffbfff134afdf R11: ffffffff89a57eff R12: 0000000000000002
R13: 0000000000000001 R14: 0000000000000ae6 R15: dffffc0000000000
 inet_twsk_purge+0x96/0x5e8 net/ipv4/inet_timewait_sock.c:267
 tcp_sk_exit_batch+0x22/0xa0 net/ipv4/tcp_ipv4.c:2722
 ops_exit_list.isra.0+0xfc/0x150 net/core/net_namespace.c:175
 cleanup_net+0x4e2/0xa60 net/core/net_namespace.c:594
 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 1809:
 save_stack+0x23/0x90 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc mm/kasan/common.c:493 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:466
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:501
 slab_post_alloc_hook mm/slab.h:520 [inline]
 slab_alloc mm/slab.c:3319 [inline]
 kmem_cache_alloc+0x121/0x710 mm/slab.c:3483
 getname_flags fs/namei.c:138 [inline]
 getname_flags+0xd6/0x5b0 fs/namei.c:128
 user_path_at_empty+0x2f/0x50 fs/namei.c:2606
 user_path_at include/linux/namei.h:60 [inline]
 do_faccessat+0x262/0x7f0 fs/open.c:398
 __do_sys_access fs/open.c:450 [inline]
 __se_sys_access fs/open.c:448 [inline]
 __x64_sys_access+0x59/0x80 fs/open.c:448
 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 1809:
 save_stack+0x23/0x90 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:455
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:463
 __cache_free mm/slab.c:3425 [inline]
 kmem_cache_free+0x86/0x320 mm/slab.c:3693
 putname+0xef/0x130 fs/namei.c:259
 filename_lookup+0x28f/0x410 fs/namei.c:2355
 user_path_at_empty+0x43/0x50 fs/namei.c:2606
 user_path_at include/linux/namei.h:60 [inline]
 do_faccessat+0x262/0x7f0 fs/open.c:398
 __do_sys_access fs/open.c:450 [inline]
 __se_sys_access fs/open.c:448 [inline]
 __x64_sys_access+0x59/0x80 fs/open.c:448
 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88806aa54480
 which belongs to the cache names_cache of size 4096
The buggy address is located 720 bytes inside of
 4096-byte region [ffff88806aa54480, ffff88806aa55480)
The buggy address belongs to the page:
page:ffffea0001aa9500 refcount:1 mapcount:0 mapping:ffff88821bc46380 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea00018f9508 ffffea00018f3c88 ffff88821bc46380
raw: 0000000000000000 ffff88806aa54480 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88806aa54600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88806aa54680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88806aa54700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff88806aa54780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88806aa54800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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