[PATCH v4 1/4] selftests/mm: move pkey selftest helpers to pkey_util.c

From: Hongfu Li

Date: Fri May 29 2026 - 03:23:24 EST


Move pkey selftest debugging helpers into shared code so both pkey
selftests can use the same tracing and abort-hook logic.

Signed-off-by: Hongfu Li <lihongfu@xxxxxxxxxx>
---
tools/testing/selftests/mm/pkey-helpers.h | 5 +-
tools/testing/selftests/mm/pkey_util.c | 86 ++++++++++++++++++++
tools/testing/selftests/mm/protection_keys.c | 83 -------------------
3 files changed, 90 insertions(+), 84 deletions(-)

diff --git a/tools/testing/selftests/mm/pkey-helpers.h b/tools/testing/selftests/mm/pkey-helpers.h
index 2c377f4e9df1..cfbb8fa2af3c 100644
--- a/tools/testing/selftests/mm/pkey-helpers.h
+++ b/tools/testing/selftests/mm/pkey-helpers.h
@@ -68,7 +68,10 @@ static inline void sigsafe_printf(const char *format, ...)
#define dprintf3(args...) dprintf_level(3, args)
#define dprintf4(args...) dprintf_level(4, args)

-extern void abort_hooks(void);
+void cat_into_file(char *str, char *file);
+void tracing_on(void);
+void tracing_off(void);
+void abort_hooks(void);
#define pkey_assert(condition) do { \
if (!(condition)) { \
dprintf0("# assert() at %s::%d test_nr: %d iteration: %d\n", \
diff --git a/tools/testing/selftests/mm/pkey_util.c b/tools/testing/selftests/mm/pkey_util.c
index 255b332f7a08..81723db43223 100644
--- a/tools/testing/selftests/mm/pkey_util.c
+++ b/tools/testing/selftests/mm/pkey_util.c
@@ -2,9 +2,95 @@
#define __SANE_USERSPACE_TYPES__
#include <sys/syscall.h>
#include <unistd.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>

#include "pkey-helpers.h"

+#if CONTROL_TRACING > 0
+static void cat_into_file(char *str, char *file)
+{
+ int fd = open(file, O_RDWR);
+ int ret;
+
+ dprintf2("%s(): writing '%s' to '%s'\n", __func__, str, file);
+ /*
+ * these need to be raw because they are called under
+ * pkey_assert()
+ */
+ if (fd < 0) {
+ fprintf(stderr, "error opening '%s'\n", str);
+ perror("error: ");
+ exit(__LINE__);
+ }
+
+ ret = write(fd, str, strlen(str));
+ if (ret != strlen(str)) {
+ perror("write to file failed");
+ fprintf(stderr, "filename: '%s' str: '%s'\n", file, str);
+ exit(__LINE__);
+ }
+ close(fd);
+}
+
+static int warned_tracing;
+static int tracing_root_ok(void)
+{
+ if (geteuid() != 0) {
+ if (!warned_tracing)
+ fprintf(stderr, "WARNING: not run as root, "
+ "can not do tracing control\n");
+ warned_tracing = 1;
+ return 0;
+ }
+ return 1;
+}
+#endif
+
+static void tracing_on(void)
+{
+#if CONTROL_TRACING > 0
+#define TRACEDIR "/sys/kernel/tracing"
+ char pidstr[32];
+
+ if (!tracing_root_ok())
+ return;
+
+ sprintf(pidstr, "%d", getpid());
+ cat_into_file("0", TRACEDIR "/tracing_on");
+ cat_into_file("\n", TRACEDIR "/trace");
+ if (1) {
+ cat_into_file("function_graph", TRACEDIR "/current_tracer");
+ cat_into_file("1", TRACEDIR "/options/funcgraph-proc");
+ } else {
+ cat_into_file("nop", TRACEDIR "/current_tracer");
+ }
+ cat_into_file(pidstr, TRACEDIR "/set_ftrace_pid");
+ cat_into_file("1", TRACEDIR "/tracing_on");
+ dprintf1("enabled tracing\n");
+#endif
+}
+
+static void tracing_off(void)
+{
+#if CONTROL_TRACING > 0
+ if (!tracing_root_ok())
+ return;
+ cat_into_file("0", "/sys/kernel/tracing/tracing_on");
+#endif
+}
+
+void abort_hooks(void)
+{
+ fflush(stdout);
+ fprintf(stderr, "running %s()...\n", __func__);
+ tracing_off();
+#ifdef SLEEP_ON_ABORT
+ sleep(SLEEP_ON_ABORT);
+#endif
+}
+
int sys_pkey_alloc(unsigned long flags, unsigned long init_val)
{
int ret = syscall(SYS_pkey_alloc, flags, init_val);
diff --git a/tools/testing/selftests/mm/protection_keys.c b/tools/testing/selftests/mm/protection_keys.c
index 9a6d954ee371..e504544e2197 100644
--- a/tools/testing/selftests/mm/protection_keys.c
+++ b/tools/testing/selftests/mm/protection_keys.c
@@ -62,89 +62,6 @@ noinline int read_ptr(int *ptr)
return *ptr;
}

-#if CONTROL_TRACING > 0
-static void cat_into_file(char *str, char *file)
-{
- int fd = open(file, O_RDWR);
- int ret;
-
- dprintf2("%s(): writing '%s' to '%s'\n", __func__, str, file);
- /*
- * these need to be raw because they are called under
- * pkey_assert()
- */
- if (fd < 0) {
- fprintf(stderr, "error opening '%s'\n", str);
- perror("error: ");
- exit(__LINE__);
- }
-
- ret = write(fd, str, strlen(str));
- if (ret != strlen(str)) {
- perror("write to file failed");
- fprintf(stderr, "filename: '%s' str: '%s'\n", file, str);
- exit(__LINE__);
- }
- close(fd);
-}
-
-static int warned_tracing;
-static int tracing_root_ok(void)
-{
- if (geteuid() != 0) {
- if (!warned_tracing)
- fprintf(stderr, "WARNING: not run as root, "
- "can not do tracing control\n");
- warned_tracing = 1;
- return 0;
- }
- return 1;
-}
-#endif
-
-static void tracing_on(void)
-{
-#if CONTROL_TRACING > 0
-#define TRACEDIR "/sys/kernel/tracing"
- char pidstr[32];
-
- if (!tracing_root_ok())
- return;
-
- sprintf(pidstr, "%d", getpid());
- cat_into_file("0", TRACEDIR "/tracing_on");
- cat_into_file("\n", TRACEDIR "/trace");
- if (1) {
- cat_into_file("function_graph", TRACEDIR "/current_tracer");
- cat_into_file("1", TRACEDIR "/options/funcgraph-proc");
- } else {
- cat_into_file("nop", TRACEDIR "/current_tracer");
- }
- cat_into_file(pidstr, TRACEDIR "/set_ftrace_pid");
- cat_into_file("1", TRACEDIR "/tracing_on");
- dprintf1("enabled tracing\n");
-#endif
-}
-
-static void tracing_off(void)
-{
-#if CONTROL_TRACING > 0
- if (!tracing_root_ok())
- return;
- cat_into_file("0", "/sys/kernel/tracing/tracing_on");
-#endif
-}
-
-void abort_hooks(void)
-{
- fflush(stdout);
- fprintf(stderr, "running %s()...\n", __func__);
- tracing_off();
-#ifdef SLEEP_ON_ABORT
- sleep(SLEEP_ON_ABORT);
-#endif
-}
-
/*
* This attempts to have roughly a page of instructions followed by a few
* instructions that do a write, and another page of instructions. That
--
2.50.1