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BUG: KASAN: slab-out-of-bounds in ipv6_gso_pull_exthdrs+0x57a/0x5f0 net/ipv6/ip6_offload.c:45
Read of size 1 at addr ffff8801c1154001 by task syz-executor4/6641

CPU: 0 PID: 6641 Comm: syz-executor4 Not tainted 4.18.0-rc2+ #26
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430
 ipv6_gso_pull_exthdrs+0x57a/0x5f0 net/ipv6/ip6_offload.c:45
 ipv6_gso_segment+0x37a/0x11e0 net/ipv6/ip6_offload.c:87
 skb_mac_gso_segment+0x3b5/0x740 net/core/dev.c:2792
 nsh_gso_segment+0x470/0xb40 net/nsh/nsh.c:111
 skb_mac_gso_segment+0x3b5/0x740 net/core/dev.c:2792
 __skb_gso_segment+0x3c3/0x880 net/core/dev.c:2865
 skb_gso_segment include/linux/netdevice.h:4079 [inline]
 validate_xmit_skb+0x640/0xf30 net/core/dev.c:3104
 __dev_queue_xmit+0xc14/0x3910 net/core/dev.c:3561
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3602
 packet_snd net/packet/af_packet.c:2919 [inline]
 packet_sendmsg+0x428e/0x6130 net/packet/af_packet.c:2944
 sock_sendmsg_nosec net/socket.c:641 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:651
 __sys_sendto+0x3d7/0x670 net/socket.c:1797
 __do_sys_sendto net/socket.c:1809 [inline]
 __se_sys_sendto net/socket.c:1805 [inline]
 __ia32_sys_sendto+0xdf/0x1a0 net/socket.c:1805
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7f94cb9
Code: 55 08 8b 88 64 cd ff ff 8b 98 68 cd ff ff 89 c8 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 1c 24 c3 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 
RSP: 002b:00000000f5f900ac EFLAGS: 00000282 ORIG_RAX: 0000000000000171
RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 0000000020000000
RDX: 0000000000000012 RSI: 0000000000000000 RDI: 00000000200000c0
RBP: 000000000000001c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6390:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554
 getname_flags+0xd0/0x5a0 fs/namei.c:140
 getname+0x19/0x20 fs/namei.c:211
 do_sys_open+0x3a2/0x760 fs/open.c:1095
 __do_sys_open fs/open.c:1119 [inline]
 __se_sys_open fs/open.c:1114 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1114
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 6390:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kmem_cache_free+0x86/0x2d0 mm/slab.c:3756
 putname+0xf2/0x130 fs/namei.c:261
 do_sys_open+0x569/0x760 fs/open.c:1110
 __do_sys_open fs/open.c:1119 [inline]
 __se_sys_open fs/open.c:1114 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1114
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8801c1154e40
 which belongs to the cache names_cache of size 4096
The buggy address is located 3647 bytes to the left of
 4096-byte region [ffff8801c1154e40, ffff8801c1155e40)
The buggy address belongs to the page:
page:ffffea0007045500 count:1 mapcount:0 mapping:ffff8801da987dc0 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffffea0006af2208 ffffea00072bd208 ffff8801da987dc0
raw: 0000000000000000 ffff8801c1154e40 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c1153f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c1153f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8801c1154000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff8801c1154080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801c1154100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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