KASAN: use-after-free Read in rdma_bind_addr

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 05d08e29 Add linux-next specific files for 20190402
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10333a97200000
kernel config: https://syzkaller.appspot.com/x/.config?x=96b7dfefc1d73906
dashboard link: https://syzkaller.appspot.com/bug?extid=68b44a1597636e0b342c
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+68b44a...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in cma_alloc_any_port
drivers/infiniband/core/cma.c:3319 [inline]
BUG: KASAN: use-after-free in cma_get_port
drivers/infiniband/core/cma.c:3471 [inline]
BUG: KASAN: use-after-free in rdma_bind_addr+0x1dfa/0x1f80
drivers/infiniband/core/cma.c:3591
Read of size 8 at addr ffff88809a696448 by task syz-executor.3/28371

CPU: 1 PID: 28371 Comm: syz-executor.3 Not tainted 5.1.0-rc3-next-20190402
#16
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x172/0x1f0 lib/dump_stack.c:113
print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
__asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
cma_alloc_any_port drivers/infiniband/core/cma.c:3319 [inline]
cma_get_port drivers/infiniband/core/cma.c:3471 [inline]
rdma_bind_addr+0x1dfa/0x1f80 drivers/infiniband/core/cma.c:3591
cma_bind_addr drivers/infiniband/core/cma.c:3121 [inline]
rdma_resolve_addr+0x437/0x21f0 drivers/infiniband/core/cma.c:3132
ucma_resolve_ip+0x153/0x210 drivers/infiniband/core/ucma.c:715
ucma_write+0x2da/0x3c0 drivers/infiniband/core/ucma.c:1696
__vfs_write+0x8d/0x110 fs/read_write.c:485
vfs_write+0x20c/0x580 fs/read_write.c:549
ksys_write+0xea/0x1f0 fs/read_write.c:598
__do_sys_write fs/read_write.c:610 [inline]
__se_sys_write fs/read_write.c:607 [inline]
__x64_sys_write+0x73/0xb0 fs/read_write.c:607
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4582b9
Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f98544c5c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004582b9
RDX: 0000000000000048 RSI: 0000000020000180 RDI: 0000000000000005
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f98544c66d4
R13: 00000000004ce188 R14: 00000000004dd8c8 R15: 00000000ffffffff

Allocated by task 28213:
save_stack+0x45/0xd0 mm/kasan/common.c:75
set_track mm/kasan/common.c:87 [inline]
__kasan_kmalloc mm/kasan/common.c:497 [inline]
__kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470
kasan_kmalloc+0x9/0x10 mm/kasan/common.c:511
__do_kmalloc mm/slab.c:3727 [inline]
__kmalloc+0x15c/0x740 mm/slab.c:3736
kmalloc include/linux/slab.h:552 [inline]
kzalloc include/linux/slab.h:742 [inline]
lsm_cred_alloc security/security.c:467 [inline]
security_prepare_creds+0x123/0x190 security/security.c:1510
prepare_creds+0x2f5/0x3f0 kernel/cred.c:280
do_faccessat+0xa2/0x7f0 fs/open.c:359
__do_sys_access fs/open.c:430 [inline]
__se_sys_access fs/open.c:428 [inline]
__x64_sys_access+0x59/0x80 fs/open.c:428
do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9:
save_stack+0x45/0xd0 mm/kasan/common.c:75
set_track mm/kasan/common.c:87 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/common.c:459
kasan_slab_free+0xe/0x10 mm/kasan/common.c:467
__cache_free mm/slab.c:3499 [inline]
kfree+0xcf/0x230 mm/slab.c:3822
security_cred_free+0xaf/0x110 security/security.c:1504
put_cred_rcu+0x129/0x4b0 kernel/cred.c:118
__rcu_reclaim kernel/rcu/rcu.h:227 [inline]
rcu_do_batch kernel/rcu/tree.c:2475 [inline]
invoke_rcu_callbacks kernel/rcu/tree.c:2788 [inline]
rcu_core+0x928/0x1390 kernel/rcu/tree.c:2769
__do_softirq+0x266/0x95a kernel/softirq.c:293

The buggy address belongs to the object at ffff88809a696440
which belongs to the cache kmalloc-32 of size 32
The buggy address is located 8 bytes inside of
32-byte region [ffff88809a696440, ffff88809a696460)
The buggy address belongs to the page:
page:ffffea000269a580 count:1 mapcount:0 mapping:ffff88812c3f01c0
index:0xffff88809a696fc1
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea000285d2c8 ffffea0002a0ab88 ffff88812c3f01c0
raw: ffff88809a696fc1 ffff88809a696000 000000010000003e 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88809a696300: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
ffff88809a696380: 00 00 fc fc fc fc fc fc fb fb fb fb fc fc fc fc
> ffff88809a696400: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
^
ffff88809a696480: 00 00 03 fc fc fc fc fc 00 00 03 fc fc fc fc fc
ffff88809a696500: fb fb fb fb fc fc fc fc 00 00 02 fc fc fc fc fc
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.