* [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
0 siblings, 1 reply; 2+ 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] 2+ 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
0 siblings, 0 replies; 2+ 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] 2+ messages in thread
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