Re: mse->metadata_version segmentation fault

[Jonathan Liu <net147@gmail.com>]

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On 12/04/2011 6:38 PM, Jonathan Liu wrote:
> Just wanted to post an additional patch to fix segmentation fault with 
> mdadm that was missed by eb28e119b03fd5149886ed516fa4bb006ad3602e.
Slightly better formatted commit patch attached.

Regards,
Jonathan

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From 2dce5f9292bba3cfe1cd89408114087b5df7638f Mon Sep 17 00:00:00 2001
From: Jonathan Liu <net147@gmail.com>
Date: Tue, 12 Apr 2011 18:28:01 +1000
Subject: [PATCH] Monitor: avoid NULL dereference with 0.90 metadata

0.90 array do not report the metadata type in /proc/mdstat, so
we cannot assume that mse->metadata_version is non-NULL.

So add an appropriate check.

This adds an additional check missed by commit
eb28e119b03fd5149886ed516fa4bb006ad3602e.
---
 Monitor.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/Monitor.c b/Monitor.c
index a3ea724..55aebeb 100644
--- a/Monitor.c
+++ b/Monitor.c
@@ -577,7 +577,8 @@ static int check_array(struct state *st, struct mdstat_ent *mdstat,
 			info[i].major = info[i].minor = 0;
 	}
 
-	if (strncmp(mse->metadata_version, "external:", 9) == 0 &&
+	if (mse->metadata_version &&
+	    strncmp(mse->metadata_version, "external:", 9) == 0 &&
 	    is_subarray(mse->metadata_version+9))
 		st->parent_dev =
 			devname2devnum(mse->metadata_version+10);
-- 
1.7.4.4