[openib-general] [PATCH] rping: Erroneous check for minumum ping buffer size

[Tom Tucker]

Well it's almost a puzzle at this point. just hard coding 10 with a
comment is probably easier to read. But ... for the curious, this will
do what you want ... but may cause you to lose your breakfast.

#define _stringify( _x ) # _x
#define stringify( _x ) _stringify( _x )

Then 

	printf("%s %d\n", stringify(INT_MAX), sizeof(INT_MAX)) 

will get you...

2147483647 10

just like you "expected". The double nested macro call is necessary to
get cpp to substitute INT_MAX for 2147483647, otherwise you get 
INT_MAX 7

Later,

On Fri, 2006-06-09 at 12:44 +0530, Pradipta Kumar Banerjee wrote:
> Pradipta Kumar Banerjee wrote:
> > rping didn't checked correctly for the minimum size of the ping
> > buffer resulting in the following error from glibc
> > 
> > "*** glibc detected *** free(): invalid next size (fast)"
> > 
> > Signed-off-by: Pradipta Kumar Banerjee <bpradipt at in.ibm.com>
> > ---
> > 
> > Index: rping.c
> > =============================================================
> > --- rping.org	2006-06-09 10:57:43.000000000 +0530
> > +++ rping.c	2006-06-09 11:00:28.000000000 +0530
> > @@ -96,6 +96,12 @@ struct rping_rdma_info {
> >  #define RPING_BUFSIZE 64*1024
> >  #define RPING_SQ_DEPTH 16
> >  
> > +/* Default string for print data and
> > + * minimum buffer size
> > + */
> > +#define RPING_MSG_FMT           "rdma-ping-%d: "
> > +#define RPING_MIN_BUFSIZE       sizeof(itoa(INT_MAX))+sizeof(RPING_MSG_FMT)
> > +
> Tom,
>    Just found that 'itoa' is not a built-in library function. The sizeof is 
> returning '4' which is not what we really want. Do we hard-code the value to 10 
> ( like #define RPING_MIN_BUFSIZE     10 + sizeof(RPING_MSG_FMT) )?
> INT_MAX is 2147483647 (10 - chars). Other options might include writing our own 
> 'itoa'.
> 
> Thanks,
> Pradipta Kumar.
> 
> >  /*
> >   * Control block struct.
> >   */
> > @@ -774,7 +780,7 @@ static void rping_test_client(struct rpi
> >  		cb->state = RDMA_READ_ADV;
> >  
> >  		/* Put some ascii text in the buffer. */
> > -		cc = sprintf(cb->start_buf, "rdma-ping-%d: ", ping);
> > +		cc = sprintf(cb->start_buf, RPING_MSG_FMT, ping);
> >  		for (i = cc, c = start; i < cb->size; i++) {
> >  			cb->start_buf[i] = c;
> >  			c++;
> > @@ -977,11 +983,11 @@ int main(int argc, char *argv[])
> >  			break;
> >  		case 'S':
> >  			cb->size = atoi(optarg);
> > -			if ((cb->size < 1) ||
> > +			if ((cb->size < RPING_MIN_BUFSIZE) ||
> >  			    (cb->size > (RPING_BUFSIZE - 1))) {
> >  				fprintf(stderr, "Invalid size %d "
> > -				       "(valid range is 1 to %d)\n",
> > -				       cb->size, RPING_BUFSIZE);
> > +				       "(valid range is %d to %d)\n",
> > +				       cb->size, RPING_MIN_BUFSIZE, RPING_BUFSIZE);
> >  				ret = EINVAL;
> >  			} else
> >  				DEBUG_LOG("size %d\n", (int) atoi(optarg));
> > 
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> >