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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 ffff8880938f0950 by task syz-executor.2/25303

CPU: 0 PID: 25303 Comm: syz-executor.2 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:arch_local_irq_restore arch/x86/include/asm/paravirt.h:768 [inline]
RIP: 0010:console_unlock+0xbc7/0xf10 kernel/printk/printk.c:2471
Code: d2 88 48 c1 e8 03 42 80 3c 30 00 0f 85 e4 02 00 00 48 83 3d ba 31 77 07 00 0f 84 91 01 00 00 e8 3f b1 16 00 48 8b 7d 98 57 9d <0f> 1f 44 00 00 e9 6d ff ff ff e8 2a b1 16 00 48 8b 7d 08 c7 05 fc
RSP: 0018:ffff88805a2df2f8 EFLAGS: 00000216 ORIG_RAX: ffffffffffffff13
RAX: 0000000000040000 RBX: 0000000000000200 RCX: ffffc9000a588000
RDX: 000000000000a79c RSI: ffffffff815bc2a1 RDI: 0000000000000216
RBP: ffff88805a2df380 R08: ffff88804843c6c0 R09: fffffbfff134afe0
R10: fffffbfff134afdf R11: ffffffff89a57eff R12: 0000000000000000
R13: ffffffff84336690 R14: dffffc0000000000 R15: ffffffff893ca670
 vprintk_emit+0x2a0/0x700 kernel/printk/printk.c:1986
 vprintk_default+0x28/0x30 kernel/printk/printk.c:2013
 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:386
 printk+0xba/0xed kernel/printk/printk.c:2046
 __nla_validate_parse.cold+0x42/0x70 lib/nlattr.c:393
 __nla_parse+0x43/0x60 lib/nlattr.c:478
 __nlmsg_parse include/net/netlink.h:666 [inline]
 nlmsg_parse_deprecated include/net/netlink.h:706 [inline]
 neigh_valid_dump_req+0x264/0x6e0 net/core/neighbour.c:2672
 neigh_dump_info+0x1f9/0x15b0 net/core/neighbour.c:2719
 netlink_dump+0x558/0xfa0 net/netlink/af_netlink.c:2244
 netlink_recvmsg+0xbb4/0xf50 net/netlink/af_netlink.c:2000
 sock_recvmsg_nosec net/socket.c:871 [inline]
 sock_recvmsg net/socket.c:889 [inline]
 sock_recvmsg+0xce/0x110 net/socket.c:885
 ___sys_recvmsg+0x271/0x5a0 net/socket.c:2480
 __sys_recvmsg+0x102/0x1d0 net/socket.c:2537
 __do_sys_recvmsg net/socket.c:2547 [inline]
 __se_sys_recvmsg net/socket.c:2544 [inline]
 __x64_sys_recvmsg+0x78/0xb0 net/socket.c:2544
 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459879
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f69f49b8c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459879
RDX: 0000000000000000 RSI: 0000000020000b00 RDI: 0000000000000005
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f69f49b96d4
R13: 00000000004c6df1 R14: 00000000004dc268 R15: 00000000ffffffff

Allocated by task 9853:
 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 9853:
 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 ffff8880938f0b80
 which belongs to the cache names_cache of size 4096
The buggy address is located 560 bytes to the left of
 4096-byte region [ffff8880938f0b80, ffff8880938f1b80)
The buggy address belongs to the page:
page:ffffea00024e3c00 refcount:1 mapcount:0 mapping:ffff88821bc46380 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea00018bfb88 ffffea000250d088 ffff88821bc46380
raw: 0000000000000000 ffff8880938f0b80 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880938f0800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880938f0880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880938f0900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                 ^
 ffff8880938f0980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880938f0a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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