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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 ffff8801d0ccb448 by task syz-executor2/14784

CPU: 1 PID: 14784 Comm: syz-executor2 Not tainted 4.15.0-rc3+ #129
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
 compat_sock_common_setsockopt+0x104/0x140 net/core/sock.c:2981
 C_SYSC_setsockopt net/compat.c:403 [inline]
 compat_SyS_setsockopt+0x17c/0x410 net/compat.c:386
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:125
RIP: 0023:0xf7fa1c79
RSP: 002b:00000000f779d08c EFLAGS: 00000296 ORIG_RAX: 000000000000016e
RAX: ffffffffffffffda RBX: 0000000000000015 RCX: 0000000000000084
RDX: 0000000000000077 RSI: 0000000020d74ff8 RDI: 0000000000000008
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 14784:
 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
 compat_sock_common_setsockopt+0x104/0x140 net/core/sock.c:2981
 C_SYSC_setsockopt net/compat.c:403 [inline]
 compat_SyS_setsockopt+0x17c/0x410 net/compat.c:386
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:125

Freed by task 11440:
 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
 inet6_create+0xc45/0x1170 net/ipv6/af_inet6.c:163
 __sock_create+0x4d4/0x850 net/socket.c:1265
 sock_create net/socket.c:1305 [inline]
 SYSC_socketpair net/socket.c:1389 [inline]
 SyS_socketpair+0x1c0/0x6f0 net/socket.c:1346
 do_syscall_32_irqs_on arch/x86/entry/common.c:327 [inline]
 do_fast_syscall_32+0x3ee/0xf9d arch/x86/entry/common.c:389
 entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:125

The buggy address belongs to the object at ffff8801d0ccb440
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 8 bytes inside of
 32-byte region [ffff8801d0ccb440, ffff8801d0ccb460)
The buggy address belongs to the page:
page:000000005e4c9f7d count:1 mapcount:0 mapping:00000000e76025c0 index:0xffff8801d0ccbfc1
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d0ccb000 ffff8801d0ccbfc1 000000010000003e
raw: ffffea000757aa60 ffffea00074334a0 ffff8801db0001c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d0ccb300: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801d0ccb380: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8801d0ccb400: fb fb fb fb fc fc fc fc 00 fc fc fc fc fc fc fc
                                              ^
 ffff8801d0ccb480: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8801d0ccb500: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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