Re: [PATCH] perf test amd ibs: avoid using executable heap

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Incorrect error check for mmap() return value leads to segmentation fault.
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commit 40ff2c8c34df3809a114852f1d0dd5630a45771c
Author: Ondrej Mosnacek <omosnace@redhat.com>

perf test amd ibs: avoid using executable heap

This commit replaces the malloc() and mprotect() combination with a single
mmap() call for creating executable memory in the AMD IBS test. This change
avoids SELinux executable heap restrictions by directly creating an
anonymous rwx mapping.

> diff --git a/tools/perf/arch/x86/tests/amd-ibs-period.c b/tools/perf/arch/x86/tests/amd-ibs-period.c
> --- a/tools/perf/arch/x86/tests/amd-ibs-period.c
> +++ b/tools/perf/arch/x86/tests/amd-ibs-period.c
[ ... ]
> @@ -59,18 +58,11 @@ static int dummy_workload_1(unsigned long count)
> +	func = mmap(NULL, page_size, PROT_READ | PROT_WRITE | PROT_EXEC,
> +		    MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
> +	if (!func) {

[Severity: Medium]
Does this error check properly handle mmap() failures? mmap() returns
MAP_FAILED ((void *)-1) rather than NULL when it fails.

If mmap() fails (e.g., due to SELinux denying execmem), this check will
evaluate to false, and the code will fall through to memcpy() into an
invalid address, triggering a segmentation fault.

> +		pr_debug("mmap() failed. %m\n");
> +		return -1;
>  	}

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Sashiko AI review · https://sashiko.dev/#/patchset/20260701054807.508994-1-omosnace@redhat.com?part=1