From: Marc Haber <mh+debian-packages@zugschlus.de>
Date: Sun, 25 May 2025 21:05:56 +0200
Subject: fix buffer overflow crash on Raspberry Pi 5 (fake NUMA architecture)

Closes: #1106234
Thanks: Gerlof Langeveld
Author: Gerlof Langeveld
Forwarded: not-needed
---
 photosyst.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 photosyst.h |  1 +
 showlinux.c | 12 ++++++++----
 3 files changed, 60 insertions(+), 4 deletions(-)

diff --git a/photosyst.c b/photosyst.c
index 2f862fd..5670393 100644
--- a/photosyst.c
+++ b/photosyst.c
@@ -2646,6 +2646,57 @@ get_ksm(struct sstat *si)
 }
 
 
+/*
+** determine if this system uses *real* NUMA rather than *fake* NUMA
+** that is the case when not all node distances have the same value
+*/
+#define	NUMADISTANCE0	"/sys/devices/system/node/node0/distance"
+
+int
+uses_realnuma(void)
+{
+	static int	realnuma = -1;
+	FILE		*fp;
+	int		i, total, nr=0, dist[10];
+	char		linebuf[1024];
+
+	if (realnuma == -1)	// first call?
+	{
+		if ( (fp = fopen(NUMADISTANCE0, "r")) != NULL)
+		{
+			if ( fgets(linebuf, sizeof(linebuf), fp) != NULL)
+			{
+				nr = sscanf(linebuf, "%d %d %d %d %d %d %d %d %d %d",
+					&dist[0], &dist[1], &dist[2], &dist[3],
+					&dist[4], &dist[5], &dist[6], &dist[7],
+					&dist[8], &dist[9]);
+			}
+
+			fclose(fp);
+		}
+
+		if (nr <= 0)
+		{
+			realnuma = 0;	// probably fake NUMA
+		}
+		else
+		{
+			// totalize all distances
+        		for (i=0, total=0; i < nr; i++)
+				total += dist[i];
+
+			// average distance not equal to the first distance?
+			if (total / i != dist[0])
+				realnuma = 1;	// real NUMA
+			else
+				realnuma = 0;	// fake NUMA
+		}
+	}
+
+	return realnuma;
+}
+
+
 #if	HTTPSTATS
 /*
 ** retrieve statistics from local HTTP daemons
diff --git a/photosyst.h b/photosyst.h
index 600fb36..ebe4115 100644
--- a/photosyst.h
+++ b/photosyst.h
@@ -468,6 +468,7 @@ void	deviatsyst(struct sstat *, struct sstat *, struct sstat *, long);
 void	totalsyst (char,           struct sstat *, struct sstat *);
 void	do_perfevents(char *, char *);
 int     isdisk_major(unsigned int);
+int	uses_realnuma(void);
 
 /*
 ** return value of isdisk_...()
diff --git a/showlinux.c b/showlinux.c
index 3bdf804..817e967 100644
--- a/showlinux.c
+++ b/showlinux.c
@@ -1969,7 +1969,7 @@ prisyst(struct sstat *sstat, int curline, int nsecs, int avgval,
 	/*
 	** memory info related for per NUMA
 	*/
-	if (sstat->memnuma.nrnuma > 1)
+	if (sstat->memnuma.nrnuma > 1 && uses_realnuma())
 	{
 		for (extra.index=lin=0;
 		     extra.index < sstat->memnuma.nrnuma && lin < maxnumalines;
@@ -2005,7 +2005,7 @@ prisyst(struct sstat *sstat, int curline, int nsecs, int avgval,
 	/*
 	** Accumulate each cpu statistic for per NUMA
 	*/
-	if (sstat->cpunuma.nrnuma > 1)
+	if (sstat->cpunuma.nrnuma > 1 && uses_realnuma())
 	{
 		for (extra.index=lin=0;
 		     extra.index < sstat->cpunuma.nrnuma && lin < maxnumalines;
@@ -2045,8 +2045,12 @@ prisyst(struct sstat *sstat, int curline, int nsecs, int avgval,
 				*highorderp = MSORTCPU;
 			}
 
-			extra.percputot = extra.pernumacputot /
-						(sstat->cpu.nrcpu/sstat->cpunuma.nrnuma);
+			if (sstat->cpunuma.numa[extra.index].nrcpu)
+				extra.percputot = extra.pernumacputot /
+					sstat->cpunuma.numa[extra.index].nrcpu;
+			else
+				extra.percputot = 1;
+
 			if (extra.percputot == 0)
 				extra.percputot = 1; /* avoid divide-by-zero */