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authorGerald Schaefer <gerald.schaefer@linux.ibm.com>2021-12-10 14:47:02 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-12-10 17:10:56 -0800
commit005a79e5c254c3f60ec269a459cc41b55028c798 (patch)
tree5e52825c831a92e5a352ed11b03065966936e7b6 /mm/slub.c
parent9ab3b0c8ef629f60ef25cb7634ad305315ae94d1 (diff)
mm/slub: fix endianness bug for alloc/free_traces attributes
On big-endian s390, the alloc/free_traces attributes produce endless output, because of always 0 idx in slab_debugfs_show(). idx is de-referenced from *v, which points to a loff_t value, with unsigned int idx = *(unsigned int *)v; This will only give the upper 32 bits on big-endian, which remain 0. Instead of only fixing this de-reference, during discussion it seemed more appropriate to change the seq_ops so that they use an explicit iterator in private loc_track struct. This patch adds idx to loc_track, which will also fix the endianness bug. Link: https://lore.kernel.org/r/20211117193932.4049412-1-gerald.schaefer@linux.ibm.com Link: https://lkml.kernel.org/r/20211126171848.17534-1-gerald.schaefer@linux.ibm.com Fixes: 64dd68497be7 ("mm: slub: move sysfs slab alloc/free interfaces to debugfs") Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Reported-by: Steffen Maier <maier@linux.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Faiyaz Mohammed <faiyazm@codeaurora.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slub.c')
-rw-r--r--mm/slub.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/mm/slub.c b/mm/slub.c
index a8626825a829..abe7db581d68 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5081,6 +5081,7 @@ struct loc_track {
unsigned long max;
unsigned long count;
struct location *loc;
+ loff_t idx;
};
static struct dentry *slab_debugfs_root;
@@ -6052,11 +6053,11 @@ __initcall(slab_sysfs_init);
#if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_DEBUG_FS)
static int slab_debugfs_show(struct seq_file *seq, void *v)
{
-
- struct location *l;
- unsigned int idx = *(unsigned int *)v;
struct loc_track *t = seq->private;
+ struct location *l;
+ unsigned long idx;
+ idx = (unsigned long) t->idx;
if (idx < t->count) {
l = &t->loc[idx];
@@ -6105,16 +6106,18 @@ static void *slab_debugfs_next(struct seq_file *seq, void *v, loff_t *ppos)
{
struct loc_track *t = seq->private;
- v = ppos;
- ++*ppos;
+ t->idx = ++(*ppos);
if (*ppos <= t->count)
- return v;
+ return ppos;
return NULL;
}
static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos)
{
+ struct loc_track *t = seq->private;
+
+ t->idx = *ppos;
return ppos;
}