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BUG: KASAN: slab-out-of-bounds in sctp_send_reset_streams+0xb03/0xc10 net/sctp/stream.c:323
Read of size 2 at addr ffff8801c4c20a88 by task syzkaller171653/3159

CPU: 1 PID: 3159 Comm: syzkaller171653 Not tainted 4.15.0-rc2-mm1+ #39
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+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:428
 sctp_send_reset_streams+0xb03/0xc10 net/sctp/stream.c:323
 sctp_setsockopt_reset_streams net/sctp/socket.c:3905 [inline]
 sctp_setsockopt+0x70d/0x5d50 net/sctp/socket.c:4195
 sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2968
 SYSC_setsockopt net/socket.c:1829 [inline]
 SyS_setsockopt+0x189/0x360 net/socket.c:1808
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x445629
RSP: 002b:00007f273622bdc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000445629
RDX: 0000000000000077 RSI: 0000000000000084 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000008 R09: 00007f273622c700
R10: 0000000020b24000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffc995416bf R14: 00007f273622c9c0 R15: 0000000000000000

Allocated by task 3159:
 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:551
 __do_kmalloc mm/slab.c:3712 [inline]
 __kmalloc_track_caller+0x15e/0x760 mm/slab.c:3727
 memdup_user+0x2c/0x90 mm/util.c:164
 sctp_setsockopt_reset_streams net/sctp/socket.c:3897 [inline]
 sctp_setsockopt+0x6a6/0x5d50 net/sctp/socket.c:4195
 sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2968
 SYSC_setsockopt net/socket.c:1829 [inline]
 SyS_setsockopt+0x189/0x360 net/socket.c:1808
 entry_SYSCALL_64_fastpath+0x1f/0x96

Freed by task 1748:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3492 [inline]
 kfree+0xca/0x250 mm/slab.c:3807
 selinux_cred_free+0x48/0x70 security/selinux/hooks.c:3815
 security_cred_free+0x48/0x80 security/security.c:995
 put_cred_rcu+0x106/0x400 kernel/cred.c:117
 __rcu_reclaim kernel/rcu/rcu.h:172 [inline]
 rcu_do_batch kernel/rcu/tree.c:2675 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2934 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2901 [inline]
 rcu_process_callbacks+0xd74/0x17d0 kernel/rcu/tree.c:2918
 __do_softirq+0x29d/0xbb2 kernel/softirq.c:285

The buggy address belongs to the object at ffff8801c4c20a80
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 8 bytes inside of
 32-byte region [ffff8801c4c20a80, ffff8801c4c20aa0)
The buggy address belongs to the page:
page:0000000063c9e2e4 count:1 mapcount:0 mapping:00000000aa7555b6 index:0xffff8801c4c20fc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801c4c20000 ffff8801c4c20fc1 0000000100000017
raw: ffffea00071312a0 ffffea00071a4460 ffff8801dac001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c4c20980: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801c4c20a00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801c4c20a80: 00 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
                      ^
 ffff8801c4c20b00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801c4c20b80: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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