[PATCH] Re: [2.6.0, pktgen] divide-by-zero

[Jörn Engel]

On Wed, 31 December 2003 06:13:16 -0500, Lennert Buytenhek wrote:
> 
> When generating packets with pktgen with count=10, I get a divide-by-zero
> oops in inject().
> 
> Line 273 in net/core/pktgen.c seems unsafe:
> 	__u64 pps = (__u32)(info->sofar * 1000) / ((__u32)(total) / 1000);
> 
> What if total < 1000 ?

Since noone else seemed to care, try this patch.  Against -test11,
yeah, I'm lazy again.

Jörn

-- 
Time? What's that? Time is only worth what you do with it.
-- Theo de Raadt

--- old/net/core/pktgen.c	2003-11-26 21:44:47.000000000 +0100
+++ new/net/core/pktgen.c	2004-01-18 16:27:10.000000000 +0100
@@ -720,7 +720,9 @@
 
 	{
 		char *p = info->result;
-		__u64 pps = (__u32)(info->sofar * 1000) / ((__u32)(total) / 1000);
+		__u32 safe_total = (__u32)(total) / 1000;
+		safe_total += 1 - (!!safe_total); /* avoid divide-by-zero */
+		__u64 pps = (__u32)(info->sofar * 1000) / safe_total;
 		__u64 bps = pps * 8 * (info->pkt_size + 4); /* take 32bit ethernet CRC into account */
 		p += sprintf(p, "OK: %llu(c%llu+d%llu) usec, %llu (%dbyte,%dfrags) %llupps %lluMb/sec (%llubps)  errors: %llu",
 			     (unsigned long long) total,
-
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