From dea403341886d7cc8338fd14461835794625b6a1 Mon Sep 17 00:00:00 2001
From: Jim Warner <james.warner@comcast.net>
Date: Fri, 17 Jun 2016 00:00:00 -0500
Subject: [PATCH] library: bug fix if libnuma.so unavailable, <STAT> api
All our numa logic was well encapsulated under #ifndef
NUMA_DISABLE (as ./configure --disable-numa), with the
exception of 1 case label. The reason it didn't create
any problems is because the sole consumer (top) itself
responded to the presence of #define NUMA_DISABLE too.
But if that option wasn't used, an oops still awaited.
When experimenting with a 32-bit library plus a 64-bit
kernel, a bug was revealed should the numa library not
have been found. Our 'reap' function must tolerate the
potential of a 0 return from that stacks_fetch_tics().
Now, if numa is desired but not possible, we'll be ok.
[ and, we'll build numa history from fresher sources ]
Signed-off-by: Jim Warner <james.warner@comcast.net>
---
proc/stat.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/proc/stat.c b/proc/stat.c
index 8b7ef63f..e39ef30d 100644
--- a/proc/stat.c
+++ b/proc/stat.c
@@ -751,6 +751,7 @@ static int stacks_fetch_tics (
this->result.stacks = this->anchor;
this->fetch.dirty_stacks = 1;
+ // callers beware, this might be zero (maybe no libnuma.so) ...
return this->result.total;
} // end: stacks_fetch_tics
@@ -1029,12 +1030,14 @@ PROCPS_EXPORT struct stat_reaped *procps_stat_reap (
return NULL;
break;
case STAT_REAP_CPUS_AND_NODES:
- if (0 > make_numa_hist(info))
- return NULL;
if (!stacks_fetch_tics(info, &info->cpus))
return NULL;
- if (!stacks_fetch_tics(info, &info->nodes))
+#ifndef NUMA_DISABLE
+ if (0 > make_numa_hist(info))
return NULL;
+ // tolerate an unexpected absence of libnuma.so ...
+ stacks_fetch_tics(info, &info->nodes);
+#endif
break;
default:
return NULL;