core-helper: add null function to obfuscate (void *)0 values

Signed-off-by: Colin Ian King <[email protected]>
ColinIanKing · Dec 11, 2023 · b40b7ce · b40b7ce
1 parent 866ebc3
commit b40b7ce
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Showing 6 changed files with 20 additions and 7 deletions.
diff --git a/core-helper.c b/core-helper.c
@@ -1415,6 +1415,18 @@ uint64_t stress_get_uint64_zero(void)
 	return g_shared->zero;
 }
 
+/*
+ *  stress_get_uint64_zero()
+ *	return null in way that force less smart
+ *	static analysers to realise we are doing this
+ *	to force a division by zero. I'd like to have
+ *	a better solution than this ghastly way.
+ */
+void *stress_get_null(void)
+{
+	return (void *)g_shared->zero;
+}
+
 /*
  *  stress_base36_encode_uint64()
  *	encode 64 bit hash of filename into a unique base 36

diff --git a/core-helper.h b/core-helper.h
@@ -77,6 +77,7 @@ extern WARN_UNUSED int stress_strcmp_munged(const char *s1, const char *s2);
 extern WARN_UNUSED ssize_t stress_get_stack_direction(void);
 extern WARN_UNUSED void *stress_get_stack_top(void *start, size_t size);
 extern WARN_UNUSED uint64_t stress_get_uint64_zero(void);
+extern WARN_UNUSED void *stress_get_null(void);
 extern int stress_temp_filename(char *path, const size_t len, const char *name,
 	const pid_t pid, const uint32_t instance, const uint64_t magic);
 extern int stress_temp_filename_args(stress_args_t *args, char *path,

diff --git a/stress-mlock.c b/stress-mlock.c
@@ -217,10 +217,10 @@ static void stress_mlock_misc(stress_args_t *args, const size_t page_size, const
 	VOID_RET(int, shim_munlock((void *)(~(uintptr_t)0 & ~(page_size - 1)), page_size << 1));
 
 	VOID_RET(int, shim_mlock((void *)0, ~(size_t)0));
-	VOID_RET(int, munlock((void *)stress_get_uint64_zero(), ~(size_t)0));
+	VOID_RET(int, munlock((void *)stress_get_null(), ~(size_t)0));
 
 	VOID_RET(int, shim_mlock((void *)0, 0));
-	VOID_RET(int, munlock((void *)stress_get_uint64_zero(), 0));
+	VOID_RET(int, munlock((void *)stress_get_null(), 0));
 
 #if defined(HAVE_MLOCKALL)
 	{

diff --git a/stress-mmap.c b/stress-mmap.c
@@ -712,8 +712,8 @@ static int stress_mmap_child(stress_args_t *args, void *ctxt)
 		/*
 		 *  Step #6, invalid unmappings
 		 */
-		(void)munmap(NULL, 0);
-		(void)munmap(NULL, ~(size_t)0);
+		(void)munmap(stress_get_null(), 0);
+		(void)munmap(stress_get_null(), ~(size_t)0);
 
 		/*
 		 *  Step #7, random choice from any of the valid/invalid

diff --git a/stress-schedpolicy.c b/stress-schedpolicy.c
@@ -278,7 +278,7 @@ static int stress_schedpolicy(stress_args_t *args)
 #if defined(__linux__)
 			/* Linux allows NULL param, will return EFAULT */
 			(void)shim_memset(&param, 0, sizeof(param));
-			VOID_RET(int, sched_getparam(pid, NULL));
+			VOID_RET(int, sched_getparam(pid, stress_get_null()));
 #endif
 
 			/* Exercise bad pid, ESRCH error */
@@ -291,7 +291,7 @@ static int stress_schedpolicy(stress_args_t *args)
 
 #if defined(__linux__)
 			/* Linux allows NULL param, will return EFAULT */
-			VOID_RET(int, sched_setparam(pid, NULL));
+			VOID_RET(int, sched_setparam(pid, stress_get_null()));
 #endif
 
 			/*

diff --git a/stress-vm-segv.c b/stress-vm-segv.c
@@ -37,7 +37,7 @@ static NOINLINE void vm_unmap_child(const size_t page_size)
 
 	len = len ^ (len >> 1);
 	while (len > page_size) {
-		(void)munmap((void *)stress_get_uint64_zero(), len - page_size);
+		(void)munmap((void *)stress_get_null(), len - page_size);
 		len >>= 1;
 #if !defined(__DragonFly__)
 		shim_clflush(addr);