From: Jeff Xu <jef...@chromium.org>

Add code to detect if the vdso is memory sealed, skip the test
if it is.

Signed-off-by: Jeff Xu <jef...@chromium.org>
---
 .../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;
+               }
+       }
+
+       return false;
+}
+
 int main(int argc, char **argv, char **envp)
 {
        pid_t child;
+       FILE *maps;
 
        ksft_print_header();
        ksft_set_plan(1);
 
+       maps = fopen("/proc/self/smaps", "r");
+       if (!maps) {
+               ksft_test_result_skip("Could not open /proc/self/smaps\n");
+               return 0;
+       }
+
+       if (vdso_sealed(maps)) {
+               ksft_test_result_skip("vdso is sealed\n");
+               return 0;
+       }
+
        child = fork();
        if (child == -1)
                ksft_exit_fail_msg("failed to fork (%d): %m\n", errno);
-- 
2.48.1.502.g6dc24dfdaf-goog


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