[linux-lvm] buffer overflow detected: lvcreate terminated

From: Eric Ren <renzhengeek@gmail.com>
To: LVM general discussion and development <linux-lvm@redhat.com>
Cc: mcsontos@redhat.com
Subject: [linux-lvm] buffer overflow detected: lvcreate terminated
Date: Tue, 2 Apr 2019 20:22:45 +0800	[thread overview]
Message-ID: <CAKM4AewTByc_vAfEkcNzfsxj6BKaXKaS-R5mEchxAvY2-cRxMg@mail.gmail.com> (raw)

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Hi Marian,

I have a lvm failure below when creating a lot of thin snapshot LVs for
containers as rootfs.

```
*** buffer overflow detected ***: lvcreate terminated\n======= Backtrace:
=========\n/lib64/libc.so.6(__fortify_*fail*
+0x37)[0x7f192c2389e7]\n/lib64/libc.so.6(+0x115b62)[0x7f192c236b62]\n/lib64/libc.so.6(+0x117947)[0x7f192c238947]\n/lib64/libdevmapper-event.so.1.02(+0x21db)[0x7f192cfd21db]\n/lib64/libdevmapper-event.so.1.02(daemon_talk+0xb5)[0x7f192cfd2a55]\n/lib64/libdevmapper-event.so.1.02(+0x331b)[0x7f192cfd331b]\n/lib64/libdevmapper-event.so.1.02(dm_event_get_registered_device+0x77)[0x7f192cfd3a47]\nlvcreate(monitor_dev_for_events+0x3cc)[0x556ec3b5d75c]\nlvcreate(monitor_dev_for_events+0x2ee)[0x556ec3b5d67e]\nlvcreate(lv_suspend_if_active+0x6cc)[0x556ec3b5f25c]\nlvcreate(+0x14196d)
```

My LVM version:
```
#lvm version
  LVM version:     2.02.180(2)-RHEL7 (2018-07-20)
  Library version: 1.02.149-RHEL7 (2018-07-20)
  Driver version:  4.35.0
```
I see you recently pushed this patch, looks like a fix for such problem:

```
commit fdb6ef8a85e9adc4805202b3200b17bd3b351982
Author: Marian Csontos <mcsontos@redhat.com>
Date:   Thu Jun 21 10:20:09 2018 +0200

    libdm: fix buffer overflow

    (cherry picked from commit 8a0af1bec882de66677e1a0cdceff841c39f92b0)
```

May I ask your help for some confirmation?

- how can we reproduce this problem?
- do you think this patch can fix my problem?

Thanks in advance!
Eric

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