From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, cl@linux.com, faiyazm@codeaurora.org,
gerald.schaefer@linux.ibm.com, gregkh@linuxfoundation.org,
iamjoonsoo.kim@lge.com, linux-mm@kvack.org, maier@linux.ibm.com,
mm-commits@vger.kernel.org, penberg@kernel.org,
rientjes@google.com, stable@vger.kernel.org,
torvalds@linux-foundation.org, vbabka@suse.cz
Subject: [patch 18/21] mm/slub: fix endianness bug for alloc/free_traces attributes
Date: Fri, 10 Dec 2021 14:47:02 -0800 [thread overview]
Message-ID: <20211210224702.RW6YwnTh2%akpm@linux-foundation.org> (raw)
In-Reply-To: <20211210144539.663efee2c80d8450e6180230@linux-foundation.org>
From: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Subject: 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>
---
mm/slub.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
--- a/mm/slub.c~mm-slub-fix-endianness-bug-for-alloc-free_traces-attributes
+++ a/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 se
{
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;
}
_
next prev parent reply other threads:[~2021-12-10 22:47 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-10 22:45 incoming Andrew Morton
2021-12-10 22:46 ` [patch 01/21] Increase default MLOCK_LIMIT to 8 MiB Andrew Morton
2021-12-11 1:08 ` Linus Torvalds
2021-12-10 22:46 ` [patch 02/21] MAINTAINERS: update kdump maintainers Andrew Morton
2021-12-10 22:46 ` [patch 03/21] mailmap: update email address for Guo Ren Andrew Morton
2021-12-10 22:46 ` [patch 04/21] filemap: remove PageHWPoison check from next_uptodate_page() Andrew Morton
2021-12-10 22:46 ` [patch 05/21] timers: implement usleep_idle_range() Andrew Morton
2021-12-10 22:46 ` [patch 06/21] mm/damon/core: fix fake load reports due to uninterruptible sleeps Andrew Morton
2021-12-10 22:46 ` [patch 07/21] mm/damon/core: use better timer mechanisms selection threshold Andrew Morton
2021-12-10 22:46 ` [patch 08/21] mm/damon/dbgfs: remove an unnecessary error message Andrew Morton
2021-12-10 22:46 ` [patch 09/21] mm/damon/core: remove unnecessary error messages Andrew Morton
2021-12-10 22:46 ` [patch 10/21] mm/damon/vaddr: remove an unnecessary warning message Andrew Morton
2021-12-10 22:46 ` [patch 11/21] mm/damon/vaddr-test: split a test function having >1024 bytes frame size Andrew Morton
2021-12-10 22:46 ` [patch 12/21] mm/damon/vaddr-test: remove unnecessary variables Andrew Morton
2021-12-10 22:46 ` [patch 13/21] selftests/damon: skip test if DAMON is running Andrew Morton
2021-12-10 22:46 ` [patch 14/21] selftests/damon: test DAMON enabling with empty target_ids case Andrew Morton
2021-12-10 22:46 ` [patch 15/21] selftests/damon: test wrong DAMOS condition ranges input Andrew Morton
2021-12-10 22:46 ` [patch 16/21] selftests/damon: test debugfs file reads/writes with huge count Andrew Morton
2021-12-10 22:46 ` [patch 17/21] selftests/damon: split test cases Andrew Morton
2021-12-10 22:47 ` Andrew Morton [this message]
2021-12-10 22:47 ` [patch 19/21] mm/memcg: relocate mod_objcg_mlstate(), get_obj_stock() and put_obj_stock() Andrew Morton
2021-12-10 22:47 ` [patch 20/21] hugetlbfs: fix issue of preallocation of gigantic pages can't work Andrew Morton
2021-12-10 22:47 ` [patch 21/21] mm: bdi: initialize bdi_min_ratio when bdi is unregistered Andrew Morton
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