* [PATCH] tools/testing/shared: catch a failed posix_memalign()
@ 2026-10-20 3:31 Liam R. Howlett (Google)
2026-10-20 9:05 ` Lorenzo Stoakes (ARM)
2026-10-20 15:10 ` Vishal Moola (Fractile)
0 siblings, 2 replies; 3+ messages in thread
From: Liam R. Howlett (Google) @ 2026-10-20 3:31 UTC (permalink / raw)
To: Andrew Morton
Cc: Lorenzo Stoakes, Matthew Wilcox, Vlastimil Babka, linux-mm,
linux-kernel, Liam R. Howlett (Google)
posix_memalign() returns zero or a positive error number and never sets
errno, so the checks for a negative return in kmem_cache_alloc_lru() and
kmem_cache_alloc_bulk() is not possible. A failed aligned allocation
carries on with the pointer unset, into the constructor or the memset().
Test for any non-zero return.
Signed-off-by: Liam R. Howlett (Google) <liam@infradead.org>
---
tools/testing/shared/linux.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/shared/linux.c b/tools/testing/shared/linux.c
index e0a0693df08f5..a37d2f86d3254 100644
--- a/tools/testing/shared/linux.c
+++ b/tools/testing/shared/linux.c
@@ -83,7 +83,7 @@ void *kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru,
} else {
pthread_mutex_unlock(&cachep->lock);
if (cachep->align) {
- if (posix_memalign(&p, cachep->align, cachep->size) < 0)
+ if (posix_memalign(&p, cachep->align, cachep->size))
return NULL;
} else {
p = malloc(cachep->size);
@@ -191,7 +191,7 @@ bool kmem_cache_alloc_bulk(struct kmem_cache *cachep, gfp_t gfp, size_t size,
if (cachep->align) {
if (posix_memalign(&p[i], cachep->align,
- cachep->size) < 0)
+ cachep->size))
break;
} else {
p[i] = malloc(cachep->size);
--
2.47.3
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] tools/testing/shared: catch a failed posix_memalign()
2026-10-20 3:31 [PATCH] tools/testing/shared: catch a failed posix_memalign() Liam R. Howlett (Google)
@ 2026-10-20 9:05 ` Lorenzo Stoakes (ARM)
2026-10-20 15:10 ` Vishal Moola (Fractile)
1 sibling, 0 replies; 3+ messages in thread
From: Lorenzo Stoakes (ARM) @ 2026-10-20 9:05 UTC (permalink / raw)
To: Liam R. Howlett (Google)
Cc: Andrew Morton, Matthew Wilcox, Vlastimil Babka, linux-mm, linux-kernel
On Mon, Oct 19, 2026 at 11:31:28PM -0400, Liam R. Howlett (Google) wrote:
> posix_memalign() returns zero or a positive error number and never sets
> errno, so the checks for a negative return in kmem_cache_alloc_lru() and
> kmem_cache_alloc_bulk() is not possible. A failed aligned allocation
> carries on with the pointer unset, into the constructor or the memset().
>
> Test for any non-zero return.
>
> Signed-off-by: Liam R. Howlett (Google) <liam@infradead.org>
LGTM so:
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
> ---
> tools/testing/shared/linux.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/shared/linux.c b/tools/testing/shared/linux.c
> index e0a0693df08f5..a37d2f86d3254 100644
> --- a/tools/testing/shared/linux.c
> +++ b/tools/testing/shared/linux.c
> @@ -83,7 +83,7 @@ void *kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru,
> } else {
> pthread_mutex_unlock(&cachep->lock);
> if (cachep->align) {
> - if (posix_memalign(&p, cachep->align, cachep->size) < 0)
> + if (posix_memalign(&p, cachep->align, cachep->size))
> return NULL;
> } else {
> p = malloc(cachep->size);
> @@ -191,7 +191,7 @@ bool kmem_cache_alloc_bulk(struct kmem_cache *cachep, gfp_t gfp, size_t size,
>
> if (cachep->align) {
> if (posix_memalign(&p[i], cachep->align,
> - cachep->size) < 0)
> + cachep->size))
> break;
> } else {
> p[i] = malloc(cachep->size);
> --
> 2.47.3
>
--
Cheers, Lorenzo
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] tools/testing/shared: catch a failed posix_memalign()
2026-10-20 3:31 [PATCH] tools/testing/shared: catch a failed posix_memalign() Liam R. Howlett (Google)
2026-10-20 9:05 ` Lorenzo Stoakes (ARM)
@ 2026-10-20 15:10 ` Vishal Moola (Fractile)
1 sibling, 0 replies; 3+ messages in thread
From: Vishal Moola (Fractile) @ 2026-10-20 15:10 UTC (permalink / raw)
To: Liam R. Howlett (Google)
Cc: Andrew Morton, Lorenzo Stoakes, Matthew Wilcox, Vlastimil Babka,
linux-mm, linux-kernel, Shuah Khan
On Mon, Oct 19, 2026 at 11:31:28PM -0400, Liam R. Howlett (Google) wrote:
> posix_memalign() returns zero or a positive error number and never sets
> errno, so the checks for a negative return in kmem_cache_alloc_lru() and
> kmem_cache_alloc_bulk() is not possible. A failed aligned allocation
> carries on with the pointer unset, into the constructor or the memset().
>
> Test for any non-zero return.
>
> Signed-off-by: Liam R. Howlett (Google) <liam@infradead.org>
Reviewed-by: Vishal Moola (Fractile) <vishal.moola@gmail.com>
It's not really a big deal, but seems this was introduced in commit
8801c35c3672c ("tools: fix -Wunused-result in linux.c"), so +CC the
author Shuah Khan.
> tools/testing/shared/linux.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/shared/linux.c b/tools/testing/shared/linux.c
> index e0a0693df08f5..a37d2f86d3254 100644
> --- a/tools/testing/shared/linux.c
> +++ b/tools/testing/shared/linux.c
> @@ -83,7 +83,7 @@ void *kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru,
> } else {
> pthread_mutex_unlock(&cachep->lock);
> if (cachep->align) {
> - if (posix_memalign(&p, cachep->align, cachep->size) < 0)
> + if (posix_memalign(&p, cachep->align, cachep->size))
> return NULL;
> } else {
> p = malloc(cachep->size);
> @@ -191,7 +191,7 @@ bool kmem_cache_alloc_bulk(struct kmem_cache *cachep, gfp_t gfp, size_t size,
>
> if (cachep->align) {
> if (posix_memalign(&p[i], cachep->align,
> - cachep->size) < 0)
> + cachep->size))
> break;
> } else {
> p[i] = malloc(cachep->size);
> --
> 2.47.3
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-10-20 3:31 [PATCH] tools/testing/shared: catch a failed posix_memalign() Liam R. Howlett (Google)
2026-10-20 9:05 ` Lorenzo Stoakes (ARM)
2026-10-20 15:10 ` Vishal Moola (Fractile)
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