* [PATCH] selftests/cgroup: check malloc return value in alloc_anon functions
@ 2026-05-11 2:16 Hongfu Li
2026-05-11 2:46 ` Muchun Song
2026-05-11 11:59 ` Vishal Moola
0 siblings, 2 replies; 4+ messages in thread
From: Hongfu Li @ 2026-05-11 2:16 UTC (permalink / raw)
To: hannes, mhocko, roman.gushchin, shakeel.butt, muchun.song, tj,
mkoutny, shuah
Cc: cgroups, linux-mm, linux-kselftest, linux-kernel, Hongfu Li
The alloc_anon() function calls malloc() without checking for a NULL
return. If memory allocation fails, a NULL pointer dereference will
occur when accessing the buffer.
Add proper error handling to return -1 when malloc() fails in all
four alloc_anon variants:
- alloc_anon()
- alloc_anon_50M_check()
- alloc_anon_noexit()
- alloc_anon_50M_check_swap()
Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
---
tools/testing/selftests/cgroup/test_memcontrol.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c
index b43da9bc20c4..8ef9c99a82eb 100644
--- a/tools/testing/selftests/cgroup/test_memcontrol.c
+++ b/tools/testing/selftests/cgroup/test_memcontrol.c
@@ -61,6 +61,11 @@ int alloc_anon(const char *cgroup, void *arg)
char *buf, *ptr;
buf = malloc(size);
+ if (buf == NULL) {
+ fprintf(stderr, "malloc() failed\n");
+ return -1;
+ }
+
for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)
*ptr = 0;
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] selftests/cgroup: check malloc return value in alloc_anon functions
2026-05-11 2:16 [PATCH] selftests/cgroup: check malloc return value in alloc_anon functions Hongfu Li
@ 2026-05-11 2:46 ` Muchun Song
2026-05-11 11:59 ` Vishal Moola
1 sibling, 0 replies; 4+ messages in thread
From: Muchun Song @ 2026-05-11 2:46 UTC (permalink / raw)
To: Hongfu Li
Cc: hannes, mhocko, roman.gushchin, shakeel.butt, tj, mkoutny, shuah,
cgroups, linux-mm, linux-kselftest, linux-kernel
> On May 11, 2026, at 10:16, Hongfu Li <lihongfu@kylinos.cn> wrote:
>
> The alloc_anon() function calls malloc() without checking for a NULL
> return. If memory allocation fails, a NULL pointer dereference will
> occur when accessing the buffer.
>
> Add proper error handling to return -1 when malloc() fails in all
> four alloc_anon variants:
> - alloc_anon()
> - alloc_anon_50M_check()
> - alloc_anon_noexit()
> - alloc_anon_50M_check_swap()
>
> Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Thanks.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] selftests/cgroup: check malloc return value in alloc_anon functions
2026-05-11 2:16 [PATCH] selftests/cgroup: check malloc return value in alloc_anon functions Hongfu Li
2026-05-11 2:46 ` Muchun Song
@ 2026-05-11 11:59 ` Vishal Moola
2026-05-12 3:06 ` Hongfu Li
1 sibling, 1 reply; 4+ messages in thread
From: Vishal Moola @ 2026-05-11 11:59 UTC (permalink / raw)
To: Hongfu Li
Cc: hannes, mhocko, roman.gushchin, shakeel.butt, muchun.song, tj,
mkoutny, shuah, cgroups, linux-mm, linux-kselftest, linux-kernel
On Mon, May 11, 2026 at 10:16:15AM +0800, Hongfu Li wrote:
> The alloc_anon() function calls malloc() without checking for a NULL
> return. If memory allocation fails, a NULL pointer dereference will
> occur when accessing the buffer.
>
> Add proper error handling to return -1 when malloc() fails in all
> four alloc_anon variants:
> - alloc_anon()
Just a nit, It looks like the below already have proper error handling.
> - alloc_anon_50M_check()
> - alloc_anon_noexit()
> - alloc_anon_50M_check_swap()
>
> Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
> ---
> tools/testing/selftests/cgroup/test_memcontrol.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c
> index b43da9bc20c4..8ef9c99a82eb 100644
> --- a/tools/testing/selftests/cgroup/test_memcontrol.c
> +++ b/tools/testing/selftests/cgroup/test_memcontrol.c
> @@ -61,6 +61,11 @@ int alloc_anon(const char *cgroup, void *arg)
> char *buf, *ptr;
>
> buf = malloc(size);
> + if (buf == NULL) {
> + fprintf(stderr, "malloc() failed\n");
> + return -1;
> + }
> +
> for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)
> *ptr = 0;
Every malloc() call in this file has this same pattern. Maybe we'd be
better off making it a helper function?
Either way:
Reviewed-by: Vishal Moola <vishal.moola@gmail.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] selftests/cgroup: check malloc return value in alloc_anon functions
2026-05-11 11:59 ` Vishal Moola
@ 2026-05-12 3:06 ` Hongfu Li
0 siblings, 0 replies; 4+ messages in thread
From: Hongfu Li @ 2026-05-12 3:06 UTC (permalink / raw)
To: vishal.moola
Cc: cgroups, hannes, lihongfu, linux-kernel, linux-kselftest,
linux-mm, mhocko, mkoutny, muchun.song, roman.gushchin,
shakeel.butt, shuah, tj
Hi Vishal,
> > diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c
> > index b43da9bc20c4..8ef9c99a82eb 100644
> > --- a/tools/testing/selftests/cgroup/test_memcontrol.c
> > +++ b/tools/testing/selftests/cgroup/test_memcontrol.c
> > @@ -61,6 +61,11 @@ int alloc_anon(const char *cgroup, void *arg)
> > char *buf, *ptr;
> >
> > buf = malloc(size);
> > + if (buf == NULL) {
> > + fprintf(stderr, "malloc() failed\n");
> > + return -1;
> > + }
> > +
> > for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)
> > *ptr = 0;
>
> Every malloc() call in this file has this same pattern. Maybe we'd be
> better off making it a helper function?
>
> Either way:
> Reviewed-by: Vishal Moola <vishal.moola@gmail.com>
Thanks for your review and valuable suggestion.
I agree with you, will refactor all malloc() checks into a common helper
function, and send out a v2 patch soon.
Best regards,
Hongfu Li
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2026-05-12 3:05 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-05-11 2:16 [PATCH] selftests/cgroup: check malloc return value in alloc_anon functions Hongfu Li
2026-05-11 2:46 ` Muchun Song
2026-05-11 11:59 ` Vishal Moola
2026-05-12 3:06 ` Hongfu Li
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox