Date:   Mon, 12 Mar 2018 18:59:02 -0700
From:   syzbot <syzbot+2287ac532caa81900a4e@...kaller.appspotmail.com>
To:     dasaratharaman.chandramouli@...el.com, dledford@...hat.com,
        don.hiatt@...el.com, ira.weiny@...el.com, jgg@...pe.ca,
        leonro@...lanox.com, linux-kernel@...r.kernel.org,
        linux-rdma@...r.kernel.org, parav@...lanox.com,
        syzkaller-bugs@...glegroups.com, viro@...iv.linux.org.uk
Subject: kernel BUG at lib/string.c:LINE! (2)

Hello,

syzbot hit the following crash on upstream commit
0c8efd610b58cb23cefdfa12015799079aef94ae (Mon Mar 12 00:25:09 2018 +0000)
Linux 4.16-rc5

So far this crash happened 2 times on upstream.
syzkaller reproducer is attached.
Raw console output is attached.
compiler: gcc (GCC) 7.1.1 20170620
.config is attached.
user-space arch: i386

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2287ac532caa81900a4e@...kaller.appspotmail.com
It will help syzbot understand when the bug is fixed. See footer for  
details.
If you forward the report, please keep this part and the footer.

audit: type=1400 audit(1520896835.087:8): avc:  denied  { map } for   
pid=4105 comm="syz-execprog" path="/root/syzkaller-shm186702042" dev="sda1"  
ino=16482 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023  
tcontext=unconfined_u:object_r:file_t:s0 tclass=file permissive=1
IPVS: ftp: loaded support on port[0] = 21
detected buffer overflow in memcpy
------------[ cut here ]------------
kernel BUG at lib/string.c:1052!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
    (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 4113 Comm: syz-executor0 Not tainted 4.16.0-rc5+ #261
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:fortify_panic+0x13/0x20 lib/string.c:1051
RSP: 0018:ffff8801ca81f8f0 EFLAGS: 00010286
RAX: 0000000000000022 RBX: 1ffff10039503f23 RCX: 0000000000000000
RDX: 0000000000000022 RSI: 1ffff10039503ed3 RDI: ffffed0039503f12
RBP: ffff8801ca81f8f0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000006 R11: 0000000000000000 R12: ffff8801ca81f998
R13: ffff8801ca81f938 R14: ffff8801ca81fa58 R15: 000000000000fa00
FS:  0000000000000000(0000) GS:ffff8801db200000(0063) knlGS:000000000a12a900
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000008138024 CR3: 00000001cbb58004 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  memcpy include/linux/string.h:344 [inline]
  ucma_join_ip_multicast+0x36b/0x3b0 drivers/infiniband/core/ucma.c:1421
  ucma_write+0x2d6/0x3d0 drivers/infiniband/core/ucma.c:1633
  __vfs_write+0xef/0x970 fs/read_write.c:480
  vfs_write+0x189/0x510 fs/read_write.c:544
  SYSC_write fs/read_write.c:589 [inline]
  SyS_write+0xef/0x220 fs/read_write.c:581
  do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
  do_fast_syscall_32+0x3ec/0xf9f arch/x86/entry/common.c:392
  entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7f9ec99
RSP: 002b:00000000ff8172cc EFLAGS: 00000282 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020000100
RDX: 0000000000000063 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Code: 08 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 0b 48 89 df e8 42 2c e3 fb eb  
de 55 48 89 fe 48 c7 c7 80 75 98 86 48 89 e5 e8 85 95 94 fb <0f> 0b 90 90  
90 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 41 56
RIP: fortify_panic+0x13/0x20 lib/string.c:1051 RSP: ffff8801ca81f8f0
---[ end trace 38d88b3acc1e3095 ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This bug is generated by a dumb bot. It may contain errors.
See https://goo.gl/tpsmEJ for details.
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