Re: [patch 00/26] Current slab allocator / SLUB patch queue

[Christoph Lameter]

On Mon, 18 Jun 2007, Michal Piotrowski wrote:

> > Does this patch fix the issue?
> Unfortunately no.
> 
> AFAIR I didn't see it in 2.6.22-rc4-mm2

Seems that I miscounted. We need a larger safe area.


SLUB: Fix behavior if the text output of list_locations overflows PAGE_SIZE

If slabs are allocated or freed from a large set of call sites (typical 
for the kmalloc area) then we may create more output than fits into
a single PAGE and sysfs only gives us one page. The output should be
truncated. This patch fixes the checks to do the truncation properly.

Signed-off-by: Christoph Lameter <clameter@xxxxxxx>

Index: linux-2.6.22-rc4-mm2/mm/slub.c
===================================================================
--- linux-2.6.22-rc4-mm2.orig/mm/slub.c	2007-06-18 09:37:41.000000000 -0700
+++ linux-2.6.22-rc4-mm2/mm/slub.c	2007-06-18 11:02:19.000000000 -0700
@@ -3649,13 +3649,15 @@ static int list_locations(struct kmem_ca
 			n += sprintf(buf + n, " pid=%ld",
 				l->min_pid);
 
-		if (num_online_cpus() > 1 && !cpus_empty(l->cpus)) {
+		if (num_online_cpus() > 1 && !cpus_empty(l->cpus) &&
+				n < PAGE_SIZE - n - 60) {
 			n += sprintf(buf + n, " cpus=");
 			n += cpulist_scnprintf(buf + n, PAGE_SIZE - n - 50,
 					l->cpus);
 		}
 
-		if (num_online_nodes() > 1 && !nodes_empty(l->nodes)) {
+		if (num_online_nodes() > 1 && !nodes_empty(l->nodes) &&
+				n < PAGE_SIZE - n - 60) {
 			n += sprintf(buf + n, " nodes=");
 			n += nodelist_scnprintf(buf + n, PAGE_SIZE - n - 50,
 					l->nodes);
-
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