Re: mdadm-2.2 SEGFAULT: mdadm --assemble --scan

[Andreas Haumer <andreas@xss.co.at>]

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Hi!

Bill Davidsen schrieb:
> Andreas Haumer wrote:
> 

- ------------------------------------------------------------------------
>>
Index: mdadm/Assemble.c
===================================================================
RCS file: /home/cvs/repository/distribution/Utilities/mdadm/Assemble.c,v
retrieving revision 1.1.1.7
diff -u -r1.1.1.7 Assemble.c
- --- mdadm/Assemble.c    5 Dec 2005 05:56:20 -0000    1.1.1.7
+++ mdadm/Assemble.c    31 Dec 2005 15:01:34 -0000
@@ -219,7 +219,7 @@
        }
        if (dfd >= 0) close(dfd);
>>
- -        if (ident->uuid_set && (!update && strcmp(update, "uuid")!=
0) &&
+        if (ident->uuid_set && (update && strcmp(update, "uuid")!= 0) &&
            (!super || same_uuid(info.uuid, ident->uuid,
tst->ss->swapuuid)==0)) {
            if ((inargv && verbose >= 0) || verbose > 0)
                fprintf(stderr, Name ": %s has wrong uuid.\n",

>>
> Is that right now? Because && evaluates to zero or one left to right,
> the parens and the "!=0" are not needed, and I assume they're in for a
> reason (other than to make the code hard to understand). A comment
> before that if would make the intention clear, I originally though the
> "(!update" was intended to be "!(update" which would explain the parens,
> but that seems wrong.

I made this modification out of the following reasoning:

It does not make sense to check if update is NULL and
then use it in a strcmp(). It only makes sense to check
if update is _not_ NULL and then do the strcmp()

(a similar code fragment can be found in the same sourcefile
several lines below)

This cures the segfault, but I can not really say if the
whole construct is logically correct (you are right, it
looks suspicious...)
That should be answered by Neil ;-)

- - andreas

- --
Andreas Haumer                     | mailto:andreas@xss.co.at
*x Software + Systeme              | http://www.xss.co.at/
Karmarschgasse 51/2/20             | Tel: +43-1-6060114-0
A-1100 Vienna, Austria             | Fax: +43-1-6060114-71
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