The patch titled
Subject: tools/mm: fix slabinfo crash when MAX_SLABS is exceeded
has been added to the -mm mm-unstable branch. Its filename is
tools-mm-fix-slabinfo-crash-when-max_slabs-is-exceeded.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/tools-mm-fix-slabinfo-crash-when-max_slabs-is-exceeded.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
Subject: tools/mm: fix slabinfo crash when MAX_SLABS is exceeded
Date: Thu, 31 Oct 2024 07:55:34 -0300
The number of slabs can easily exceed the hard coded MAX_SLABS in the
slabinfo tool, causing it to overwrite memory and crash.
Increase the value of MAX_SLABS, and check if that has been exceeded for
each new slab, instead of at the end when it's already too late. Also
move the check for MAX_ALIASES into the loop body.
Link: https://lkml.kernel.org/r/20241031105534.565533-1-marc.c.dionne@xxxxxxxxx
Signed-off-by: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/mm/slabinfo.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
--- a/tools/mm/slabinfo.c~tools-mm-fix-slabinfo-crash-when-max_slabs-is-exceeded
+++ a/tools/mm/slabinfo.c
@@ -21,7 +21,7 @@
#include <regex.h>
#include <errno.h>
-#define MAX_SLABS 500
+#define MAX_SLABS 2000
#define MAX_ALIASES 500
#define MAX_NODES 1024
@@ -1228,6 +1228,8 @@ static void read_slab_dir(void)
continue;
switch (de->d_type) {
case DT_LNK:
+ if (alias - aliasinfo == MAX_ALIASES)
+ fatal("Too many aliases\n");
alias->name = strdup(de->d_name);
count = readlink(de->d_name, buffer, sizeof(buffer)-1);
@@ -1242,6 +1244,8 @@ static void read_slab_dir(void)
alias++;
break;
case DT_DIR:
+ if (slab - slabinfo == MAX_SLABS)
+ fatal("Too many slabs\n");
if (chdir(de->d_name))
fatal("Unable to access slab %s\n", slab->name);
slab->name = strdup(de->d_name);
@@ -1312,10 +1316,6 @@ static void read_slab_dir(void)
slabs = slab - slabinfo;
actual_slabs = slabs;
aliases = alias - aliasinfo;
- if (slabs > MAX_SLABS)
- fatal("Too many slabs\n");
- if (aliases > MAX_ALIASES)
- fatal("Too many aliases\n");
}
static void output_slabs(void)
_
Patches currently in -mm which might be from marc.dionne@xxxxxxxxxxxx are
tools-mm-fix-slabinfo-crash-when-max_slabs-is-exceeded.patch
