general protection fault in rdma_init_qp_attr (2)

[syzbot]

Hello,

syzbot hit the following crash on upstream commit
f36b7534b83357cf52e747905de6d65b4f7c2512 (Fri Mar 23 01:48:43 2018 +0000)
Merge branch 'akpm' (patches from Andrew)
syzbot dashboard link:
https://syzkaller.appspot.com/bug?extid=7b62c837c2516f8f38c8

So far this crash happened 14 times on upstream.
C reproducer is attached.
syzkaller reproducer is attached.
Raw console output is attached.
.config is attached.
compiler: gcc (GCC) 7.1.1 20170620

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Reported-by: syzbot+7b62c8...@syzkaller.appspotmail.com
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audit: type=1400 audit(1521831694.945:6): avc: denied { map } for
pid=4084 comm="bash" path="/bin/bash" dev="sda1" ino=1457
scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1
audit: type=1400 audit(1521831701.351:7): avc: denied { map } for
pid=4098 comm="syzkaller148426" path="/root/syzkaller148426363" dev="sda1"
ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 4098 Comm: syzkaller148426 Not tainted 4.16.0-rc6+ #363
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:rdma_cap_ib_cm include/rdma/ib_verbs.h:2661 [inline]
RIP: 0010:rdma_init_qp_attr+0x8b/0x720 drivers/infiniband/core/cma.c:1025
RSP: 0018:ffff8801cc797840 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff8801bb4976c0 RCX: ffffffff841bbf8f
RDX: 0000000000000029 RSI: ffff8801cc7979c8 RDI: 0000000000000148
RBP: ffff8801cc797880 R08: ffffed00398f2f4e R09: ffff8801cc7979cc
R10: 0000000000000000 R11: ffffed00398f2f4d R12: ffff8801cc7979c8
R13: ffff8801cc797908 R14: 0000000000000000 R15: ffff8801cc7978c8
FS: 00000000007b0880(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055c67ffbb0f0 CR3: 00000001cc38a006 CR4: 00000000001606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
ucma_init_qp_attr+0x251/0x440 drivers/infiniband/core/ucma.c:1172
ucma_write+0x2d6/0x3d0 drivers/infiniband/core/ucma.c:1649
__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_64+0x281/0x940 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x43fdc9
RSP: 002b:00007ffe0daacb28 EFLAGS: 00000217 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fdc9
RDX: 0000000000000057 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000217 R12: 00000000004016f0
R13: 0000000000401780 R14: 0000000000000000 R15: 0000000000000000
Code: 00 00 00 fc ff df 80 3c 02 00 0f 85 8c 06 00 00 4c 8b 33 48 b8 00 00
00 00 00 fc ff df 49 8d be 48 01 00 00 48 89 fa 48 c1 ea 03 <80> 3c 02 00
0f 85 5d 06 00 00 44 0f b6 7d d4 48 b8 00 00 00 00
RIP: rdma_cap_ib_cm include/rdma/ib_verbs.h:2661 [inline] RSP:
ffff8801cc797840
RIP: rdma_init_qp_attr+0x8b/0x720 drivers/infiniband/core/cma.c:1025 RSP:
ffff8801cc797840
---[ end trace f0e61529df46d8ef ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
(ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


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[syzbot]

Hello,

syzbot tried to test the proposed patch but build/boot failed:

failed to checkout kernel repo: failed to run /usr/bin/git [git fetch
--no-tags --depth=1 https://github.com/rolandd/qla-target.git syzk]: exit
status 128
fatal: Couldn't find remote ref syzk



Tested on https://github.com/rolandd/qla-target.git/syzk commit
[unknown]

compiler: gcc (GCC) 7.1.1 20170620

Patch: https://syzkaller.appspot.com/x/patch.diff?id=6046569639968768

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger
crash:

Reported-and-tested-by:
syzbot+7b62c8...@syzkaller.appspotmail.com

Note: the tag will also help syzbot to understand when the bug is fixed.

Tested on https://github.com/rolandd/qla-target.git/syzk commit

b7f20dcbfd96cf56a0f81dc67ea68f0c58ce91f7 (Mon Mar 26 21:39:01 2018 +0000)
RDMA/ucma: Fix userspace-triggerable crash in rdma_init_qp_attr()

compiler: gcc (GCC) 7.1.1 20170620

Patch: https://syzkaller.appspot.com/x/patch.diff?id=5177223027884032
Kernel config:
https://syzkaller.appspot.com/x/.config?id=-2340295454854568752


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