Hello, all!
while compiling the kernel (2.6.1) I have spotted the following warning:
net/ipv6/ndisc.c: In function `ndisc_router_discovery':
net/ipv6/ndisc.c:1113: warning: comparison is always true due to limited range
of data type
net/ipv6/ndisc.c:1121: warning: comparison is always true due to limited range
of data type
The corresponding lines are these:
__u32 rtime = ntohl(ra_msg->retrans_timer);
Here ---> if (rtime && rtime/1000 < (MAX_SCHEDULE_TIMEOUT/HZ)) {
rtime = (rtime*HZ)/1000;
if (rtime < HZ/10)
rtime = HZ/10;
in6_dev->nd_parms->retrans_time = rtime;
}
rtime = ntohl(ra_msg->reachable_time);
and here --> if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/(3*HZ)) {
rtime = (rtime*HZ)/1000;
The MAX_SCHEDULE_TIMEOUT is #defined to LONG_MAX in include/linux/sched.h,
which is 2^63-1 or so on AMD64. I propose the following fix:
--- net/ipv6/ndisc.c.orig 2004-01-29 22:03:50.553745520 +0100
+++ net/ipv6/ndisc.c 2004-01-29 22:06:39.973989728 +0100
@@ -995,6 +995,9 @@
}
}
+#define MAX_SCHEDULE_TIMEOUT_32 (MAX_SCHEDULE_TIMEOUT/HZ > (1U<<31) ? \
+ (1U<<31) : MAX_SCHEDULE_TIMEOUT/HZ)
+
static void ndisc_router_discovery(struct sk_buff *skb)
{
struct ra_msg *ra_msg = (struct ra_msg *) skb->h.raw;
@@ -1110,7 +1113,7 @@
if (in6_dev->nd_parms) {
__u32 rtime = ntohl(ra_msg->retrans_timer);
- if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/HZ) {
+ if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT_32) {
rtime = (rtime*HZ)/1000;
if (rtime < HZ/10)
rtime = HZ/10;
@@ -1118,7 +1121,7 @@
}
rtime = ntohl(ra_msg->reachable_time);
- if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT/(3*HZ)) {
+ if (rtime && rtime/1000 < MAX_SCHEDULE_TIMEOUT_32/3) {
rtime = (rtime*HZ)/1000;
if (rtime < HZ/10)
Do you think this is a correct fix? If so, please apply. Hope
this helps,
-Yenya
--
| Jan "Yenya" Kasprzak <kas at {fi.muni.cz - work | yenya.net - private}> |
| GPG: ID 1024/D3498839 Fingerprint 0D99A7FB206605D7 8B35FCDE05B18A5E |
| http://www.fi.muni.cz/~kas/ Czech Linux Homepage: http://www.linux.cz/ |
Any compiler or language that likes to hide things like memory allocations
behind your back just isn't a good choice for a kernel. --Linus Torvalds
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