syzbot

IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
==================================================================
BUG: KASAN: use-after-free in sctp_epaddr_lookup_transport+0xacb/0xb20 net/sctp/input.c:971
Read of size 8 at addr ffff8881d25e2bf0 by task syz-executor5/8936

CPU: 0 PID: 8936 Comm: syz-executor5 Not tainted 4.20.0-rc2+ #117
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+0x244/0x39d lib/dump_stack.c:113
 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 sctp_epaddr_lookup_transport+0xacb/0xb20 net/sctp/input.c:971
 sctp_endpoint_lookup_assoc+0xe0/0x290 net/sctp/endpointola.c:338
 sctp_addr_id2transport+0x1f8/0x370 net/sctp/socket.c:279
 sctp_getsockopt_peer_addr_params+0x17c/0x1260 net/sctp/socket.c:5613
 sctp_getsockopt+0x44f9/0x7d32 net/sctp/socket.c:7462
 sock_common_getsockopt+0x9a/0xe0 net/core/sock.c:2937
 __sys_getsockopt+0x1ad/0x390 net/socket.c:1939
 __do_sys_getsockopt net/socket.c:1950 [inline]
 __se_sys_getsockopt net/socket.c:1947 [inline]
 __x64_sys_getsockopt+0xbe/0x150 net/socket.c:1947
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457569
Code: fd b3 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 b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fac2f229c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000457569
RDX: 0000000000000009 RSI: 0000000000000084 RDI: 0000000000000006
RBP: 000000000072c180 R08: 000000002044fffc R09: 0000000000000000
R10: 0000000020a68000 R11: 0000000000000246 R12: 00007fac2f22a6d4
R13: 00000000004c8318 R14: 00000000004ce200 R15: 00000000ffffffff

Allocated by task 8900:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
 kmem_cache_alloc_trace+0x152/0x750 mm/slab.c:3620
 kmalloc include/linux/slab.h:546 [inline]
 kzalloc include/linux/slab.h:741 [inline]
 sctp_association_new+0x14e/0x2290 net/sctp/associola.c:311
 sctp_sendmsg_new_asoc+0x39c/0x11f0 net/sctp/socket.c:1723
 sctp_sendmsg+0x18a5/0x1da0 net/sctp/socket.c:2086
 inet_sendmsg+0x1a1/0x690 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:631
 __sys_sendto+0x3d7/0x670 net/socket.c:1788
 __do_sys_sendto net/socket.c:1800 [inline]
 __se_sys_sendto net/socket.c:1796 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1796
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 8936:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kfree+0xcf/0x230 mm/slab.c:3817
 sctp_association_destroy net/sctp/associola.c:437 [inline]
 sctp_association_put+0x264/0x350 net/sctp/associola.c:889
 sctp_transport_destroy net/sctp/transport.c:180 [inline]
 sctp_transport_put+0x186/0x1f0 net/sctp/transport.c:340
 sctp_hash_cmp+0x1ef/0x260 net/sctp/input.c:825
 __rhashtable_lookup include/linux/rhashtable.h:483 [inline]
 rhltable_lookup include/linux/rhashtable.h:566 [inline]
 sctp_epaddr_lookup_transport+0x4fe/0xb20 net/sctp/input.c:967
 sctp_endpoint_lookup_assoc+0xe0/0x290 net/sctp/endpointola.c:338
 sctp_addr_id2transport+0x1f8/0x370 net/sctp/socket.c:279
 sctp_getsockopt_peer_addr_params+0x17c/0x1260 net/sctp/socket.c:5613
 sctp_getsockopt+0x44f9/0x7d32 net/sctp/socket.c:7462
 sock_common_getsockopt+0x9a/0xe0 net/core/sock.c:2937
 __sys_getsockopt+0x1ad/0x390 net/socket.c:1939
 __do_sys_getsockopt net/socket.c:1950 [inline]
 __se_sys_getsockopt net/socket.c:1947 [inline]
 __x64_sys_getsockopt+0xbe/0x150 net/socket.c:1947
 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 ffff8881d25e2b40
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 176 bytes inside of
 4096-byte region [ffff8881d25e2b40, ffff8881d25e3b40)
The buggy address belongs to the page:
page:ffffea0007497880 count:1 mapcount:0 mapping:ffff8881da800dc0 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000010200(slab|head)
raw: 02fffc0000010200 ffffea00074ac508 ffffea0007497908 ffff8881da800dc0
kobject: 'loop4' (00000000cd5e5170): fill_kobj_path: path = '/devices/virtual/block/loop4'
raw: 0000000000000000 ffff8881d25e2b40 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881d25e2a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881d25e2b00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff8881d25e2b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                             ^
 ffff8881d25e2c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881d25e2c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================