[PATCH] Re: [2.6.0, pktgen] divide-by-zero
From: Robert Olsson <hidden>
Date: 2004-01-18 23:34:46
Also in:
lkml
Hello! Jörn Engel writes: > 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. Sorry I missed Lennerts original posting... I suggest the patch below to get integer precision at very short time intervals too.
--- linux-2.6.1/net/core/pktgen.c.orig Sun Jan 18 21:56:56 2004
+++ linux-2.6.1/net/core/pktgen.c Sun Jan 18 23:15:03 2004@@ -88,7 +88,7 @@ #define cycles() ((u32)get_cycles()) -#define VERSION "pktgen version 1.3" +#define VERSION "pktgen version 1.31" static char version[] __initdata = "pktgen.c: v1.3: Packet Generator for packet performance testing.\n";
@@ -720,8 +720,18 @@ { char *p = info->result; - __u64 pps = (__u32)(info->sofar * 1000) / ((__u32)(total) / 1000); - __u64 bps = pps * 8 * (info->pkt_size + 4); /* take 32bit ethernet CRC into account */ + __u64 bps, pps = 0; + + if (total > 1000) + pps = (__u32)(info->sofar * 1000) / ((__u32)(total) / 1000); + else if(total > 100) + pps = (__u32)(info->sofar * 10000) / ((__u32)(total) / 100); + else if(total > 10) + pps = (__u32)(info->sofar * 100000) / ((__u32)(total) / 10); + else if(total > 1) + pps = (__u32)(info->sofar * 1000000) / (__u32)total; + + 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, (unsigned long long) (total - idle),
Cheers. --ro