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BUG: KASAN: slab-out-of-bounds in tcp_probe_timer net/ipv4/tcp_timer.c:360 [inline]
BUG: KASAN: slab-out-of-bounds in tcp_write_timer_handler+0x8c6/0x8d0 net/ipv4/tcp_timer.c:596
Read of size 4 at addr ffff888099f54690 by task udevd/9935

CPU: 0 PID: 9935 Comm: udevd Not tainted 5.3.0-rc6+ #179
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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:__handle_mm_fault+0x7e3/0x3f20 mm/memory.c:3886
Code: f6 0f 84 ed 0b 00 00 41 bf 01 00 00 00 e8 05 63 d4 ff 48 b8 00 00 00 00 00 fc ff df 48 03 85 d0 fe ff ff 48 c7 00 00 00 00 00 <c7> 40 08 00 00 00 00 48 c7 40 14 00 00 00 00 44 89 f8 48 8b 4d d0
RSP: 0000:ffff888088a7fce0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: ffffed101114ffa3 RBX: 800000008937b865 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff819e10db RDI: 0000000000000001
RBP: ffff888088a7fe40 R08: 1ffff11012dd7b4a R09: ffffed1012dd7b4b
R10: ffffed1012dd7b4a R11: ffff888096ebda53 R12: ffff88808e308df8
R13: ffff888088a7fe18 R14: 0000000000000055 R15: 0000000000000008
 handle_mm_fault+0x1b5/0x6b0 mm/memory.c:4001
 do_user_addr_fault arch/x86/mm/fault.c:1441 [inline]
 __do_page_fault+0x536/0xdd0 arch/x86/mm/fault.c:1506
 do_page_fault+0x38/0x590 arch/x86/mm/fault.c:1530
 page_fault+0x39/0x40 arch/x86/entry/entry_64.S:1202
RIP: 0033:0x7fe20359a111
Code: f6 44 35 08 01 0f 84 96 02 00 00 49 83 65 08 fe 49 8d 44 24 58 48 8b 50 10 48 3b 42 18 0f 85 b2 04 00 00 48 81 fd ff 03 00 00 <48> 89 53 10 48 89 43 18 76 10 48 c7 43 20 00 00 00 00 48 c7 43 28
RSP: 002b:00007ffd47d77b00 EFLAGS: 00010297
RAX: 00007fe2038abe98 RBX: 0000000000fbfe70 RCX: 00000000000200c0
RDX: 0000000000fc07c0 RSI: 0000000000000000 RDI: 00007fe2038abe40
RBP: 0000000000000210 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe2038abe40
R13: 0000000000fc0080 R14: 0000000000000040 R15: 000000000000000b

Allocated by task 9981:
 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
 getname fs/namei.c:209 [inline]
 user_path_mountpoint_at+0x29/0x50 fs/namei.c:2745
 ksys_umount+0x167/0xf00 fs/namespace.c:1680
 __do_sys_umount fs/namespace.c:1706 [inline]
 __se_sys_umount fs/namespace.c:1704 [inline]
 __x64_sys_umount+0x54/0x80 fs/namespace.c:1704
 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9981:
 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_mountpoint+0x26f/0x3c0 fs/namei.c:2723
 user_path_mountpoint_at+0x3a/0x50 fs/namei.c:2745
 ksys_umount+0x167/0xf00 fs/namespace.c:1680
 __do_sys_umount fs/namespace.c:1706 [inline]
 __se_sys_umount fs/namespace.c:1704 [inline]
 __x64_sys_umount+0x54/0x80 fs/namespace.c:1704
 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 ffff888099f54740
 which belongs to the cache names_cache of size 4096
The buggy address is located 176 bytes to the left of
 4096-byte region [ffff888099f54740, ffff888099f55740)
The buggy address belongs to the page:
page:ffffea000267d500 refcount:1 mapcount:0 mapping:ffff88821bc46380 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea00023e7708 ffffea00018a4488 ffff88821bc46380
raw: 0000000000000000 ffff888099f54740 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888099f54580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888099f54600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888099f54680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                         ^
 ffff888099f54700: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff888099f54780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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