================================================================== BUG: KASAN: slab-out-of-bounds in ip6_dst_idev include/net/ip6_fib.h:192 [inline] BUG: KASAN: slab-out-of-bounds in ip6_xmit+0x1f76/0x2260 net/ipv6/ip6_output.c:264 Read of size 8 at addr ffff8801cf2a6018 by task syz-executor3/14184 CPU: 0 PID: 14184 Comm: syz-executor3 Not tainted 4.16.0-rc4+ #254 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report+0x23c/0x360 mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 ip6_dst_idev include/net/ip6_fib.h:192 [inline] ip6_xmit+0x1f76/0x2260 net/ipv6/ip6_output.c:264 inet6_csk_xmit+0x2fc/0x580 net/ipv6/inet6_connection_sock.c:139 l2tp_xmit_core net/l2tp/l2tp_core.c:1053 [inline] l2tp_xmit_skb+0x105f/0x1410 net/l2tp/l2tp_core.c:1148 pppol2tp_sendmsg+0x470/0x670 net/l2tp/l2tp_ppp.c:341 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg+0xca/0x110 net/socket.c:639 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2047 __sys_sendmsg+0xe5/0x210 net/socket.c:2081 SYSC_sendmsg net/socket.c:2092 [inline] SyS_sendmsg+0x2d/0x50 net/socket.c:2088 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x453e69 RSP: 002b:00007fe7a5e3dc68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fe7a5e3e6d4 RCX: 0000000000453e69 RDX: 0000000000000081 RSI: 000000002037ffc8 RDI: 0000000000000016 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000004c3 R14: 00000000006f72e8 R15: 0000000000000000 Allocated by task 12288: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:552 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3541 getname_flags+0xcb/0x580 fs/namei.c:138 user_path_at_empty+0x2d/0x50 fs/namei.c:2568 user_path_at include/linux/namei.h:57 [inline] SYSC_faccessat fs/open.c:384 [inline] SyS_faccessat fs/open.c:353 [inline] SYSC_access fs/open.c:431 [inline] SyS_access+0x22c/0x6a0 fs/open.c:429 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 12288: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527 __cache_free mm/slab.c:3485 [inline] kmem_cache_free+0x83/0x2a0 mm/slab.c:3743 putname+0xee/0x130 fs/namei.c:258 filename_lookup+0x315/0x500 fs/namei.c:2323 user_path_at_empty+0x40/0x50 fs/namei.c:2568 user_path_at include/linux/namei.h:57 [inline] SYSC_faccessat fs/open.c:384 [inline] SyS_faccessat fs/open.c:353 [inline] SYSC_access fs/open.c:431 [inline] SyS_access+0x22c/0x6a0 fs/open.c:429 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff8801cf2a6cc0 which belongs to the cache names_cache of size 4096 The buggy address is located 3240 bytes to the left of 4096-byte region [ffff8801cf2a6cc0, ffff8801cf2a7cc0) The buggy address belongs to the page: page:ffffea00073ca980 count:1 mapcount:0 mapping:ffff8801cf2a6cc0 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000008100(slab|head) raw: 02fffc0000008100 ffff8801cf2a6cc0 0000000000000000 0000000100000001 raw: ffffea0006d1d7a0 ffffea0006d1ffa0 ffff8801da5d6600 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801cf2a5f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8801cf2a5f80: 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801cf2a6000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8801cf2a6080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801cf2a6100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================