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BUG: KASAN: slab-out-of-bounds in sctp_send_reset_streams+0xadf/0xc10 net/sctp/stream.c:314
Read of size 2 at addr ffff8801cf124708 by task syz-executor4/11853

CPU: 0 PID: 11853 Comm: syz-executor4 Not tainted 4.15.0-rc2+ #214
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+0xadf/0xc10 net/sctp/stream.c:314
 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: 0033:0x452a39
RSP: 002b:00007fb6fa111c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000758020 RCX: 0000000000452a39
RDX: 0000000000000077 RSI: 0000000000000084 RDI: 0000000000000015
RBP: 000000000000055c R08: 0000000000000008 R09: 0000000000000000
R10: 0000000020e73ff8 R11: 0000000000000212 R12: 00000000006f6140
R13: 00000000ffffffff R14: 00007fb6fa1126d4 R15: 0000000000000000

Allocated by task 11853:
 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:3711 [inline]
 __kmalloc_track_caller+0x15e/0x760 mm/slab.c:3726
 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 10048:
 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:3491 [inline]
 kfree+0xca/0x250 mm/slab.c:3806
 free_modprobe_argv+0x54/0xa0 kernel/kmod.c:66
 call_usermodehelper_freeinfo kernel/umh.c:42 [inline]
 call_usermodehelper_exec+0x157/0x4a0 kernel/umh.c:458
 call_modprobe kernel/kmod.c:99 [inline]
 __request_module+0x3ff/0xc00 kernel/kmod.c:171
 __sock_create+0x5f9/0x850 net/socket.c:1246
 sock_create net/socket.c:1305 [inline]
 SYSC_socket net/socket.c:1335 [inline]
 SyS_socket+0xeb/0x1d0 net/socket.c:1315
 entry_SYSCALL_64_fastpath+0x1f/0x96

The buggy address belongs to the object at ffff8801cf124700
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 8 bytes inside of
 32-byte region [ffff8801cf124700, ffff8801cf124720)
The buggy address belongs to the page:
page:00000000d220049b count:1 mapcount:0 mapping:00000000e27d409f index:0xffff8801cf124fc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801cf124000 ffff8801cf124fc1 0000000100000037
raw: ffffea00073fe260 ffffea00071390e0 ffff8801db0001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801cf124600: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801cf124680: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801cf124700: 00 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
                      ^
 ffff8801cf124780: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801cf124800: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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