On Wed, Feb 12, 2025 at 03:21:50AM +0000, jeffxu@xxxxxxxxxxxx wrote:
> From: Jeff Xu <jeffxu@xxxxxxxxxxxx>
>
> Add code to detect if the vdso is memory sealed, skip the test
> if it is.
>
> Signed-off-by: Jeff Xu <jeffxu@xxxxxxxxxxxx>
> ---
> .../testing/selftests/x86/test_mremap_vdso.c | 38 +++++++++++++++++++
> 1 file changed, 38 insertions(+)
>
> diff --git a/tools/testing/selftests/x86/test_mremap_vdso.c b/tools/testing/selftests/x86/test_mremap_vdso.c
> index d53959e03593..c68077c56b22 100644
> --- a/tools/testing/selftests/x86/test_mremap_vdso.c
> +++ b/tools/testing/selftests/x86/test_mremap_vdso.c
> @@ -14,6 +14,7 @@
> #include <errno.h>
> #include <unistd.h>
> #include <string.h>
> +#include <stdbool.h>
>
> #include <sys/mman.h>
> #include <sys/auxv.h>
> @@ -55,13 +56,50 @@ static int try_to_remap(void *vdso_addr, unsigned long size)
>
> }
>
> +#define VDSO_NAME "[vdso]"
> +#define VMFLAGS "VmFlags:"
> +#define MSEAL_FLAGS "sl"
> +#define MAX_LINE_LEN 512
> +
> +bool vdso_sealed(FILE *maps)
> +{
> + char line[MAX_LINE_LEN];
> + bool has_vdso = false;
> +
> + while (fgets(line, sizeof(line), maps)) {
> + if (strstr(line, VDSO_NAME))
> + has_vdso = true;
> +
> + if (has_vdso && !strncmp(line, VMFLAGS, strlen(VMFLAGS))) {
> + if (strstr(line, MSEAL_FLAGS))
> + return true;
> +
> + return false;
This only tests that any mapping after the vdso is sealed.
There is a real parser for /proc/self/smaps in
tools/testing/selftests/mm/vm_util.[ch], see check_vmflag_io().
> + }
> + }
> +
> + return false;
> +}
<snip>
