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authorGustavo Luiz Duarte <gustavold@linux.ibm.com>2020-02-11 00:38:31 -0300
committerMichael Ellerman <mpe@ellerman.id.au>2020-03-25 12:06:30 +1100
commit0f8f554e5244f56f496b4ce30ada1126fe290345 (patch)
tree74666d64331a65f96e26716957162f185e777553 /tools/testing/selftests/powerpc
parent915b7f6f9a5e232c138bb36743a1fdb0fcf2c432 (diff)
selftests/powerpc: Don't rely on segfault to rerun the test
The test case tm-signal-context-force-tm expects a segfault to happen on returning from signal handler, and then does a setcontext() to run the test again. However, the test doesn't always segfault, causing the test to run a single time. This patch fixes the test by putting it within a loop and jumping, via setcontext, just prior to the loop in case it segfaults. This way we get the desired behavior (run the test COUNT_MAX times) regardless if it segfaults or not. This also reduces the use of setcontext for control flow logic, keeping it only in the segfault handler. Also, since 'count' is changed within the signal handler, it is declared as volatile to prevent any compiler optimization getting confused with asynchronous changes. Signed-off-by: Gustavo Luiz Duarte <gustavold@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200211033831.11165-3-gustavold@linux.ibm.com
Diffstat (limited to 'tools/testing/selftests/powerpc')
-rw-r--r--tools/testing/selftests/powerpc/tm/tm-signal-context-force-tm.c74
1 files changed, 35 insertions, 39 deletions
diff --git a/tools/testing/selftests/powerpc/tm/tm-signal-context-force-tm.c b/tools/testing/selftests/powerpc/tm/tm-signal-context-force-tm.c
index 31717625f318..421cb082f6be 100644
--- a/tools/testing/selftests/powerpc/tm/tm-signal-context-force-tm.c
+++ b/tools/testing/selftests/powerpc/tm/tm-signal-context-force-tm.c
@@ -42,9 +42,10 @@
#endif
/* Setting contexts because the test will crash and we want to recover */
-ucontext_t init_context, main_context;
+ucontext_t init_context;
-static int count, first_time;
+/* count is changed in the signal handler, so it must be volatile */
+static volatile int count;
void usr_signal_handler(int signo, siginfo_t *si, void *uc)
{
@@ -98,11 +99,6 @@ void usr_signal_handler(int signo, siginfo_t *si, void *uc)
void seg_signal_handler(int signo, siginfo_t *si, void *uc)
{
- if (count == COUNT_MAX) {
- /* Return to tm_signal_force_msr() and exit */
- setcontext(&main_context);
- }
-
count++;
/* Reexecute the test */
@@ -126,37 +122,41 @@ void tm_trap_test(void)
*/
getcontext(&init_context);
- /* Allocated an alternative signal stack area */
- ss.ss_sp = mmap(NULL, SIGSTKSZ, PROT_READ | PROT_WRITE,
- MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
- ss.ss_size = SIGSTKSZ;
- ss.ss_flags = 0;
+ while (count < COUNT_MAX) {
+ /* Allocated an alternative signal stack area */
+ ss.ss_sp = mmap(NULL, SIGSTKSZ, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+ ss.ss_size = SIGSTKSZ;
+ ss.ss_flags = 0;
- if (ss.ss_sp == (void *)-1) {
- perror("mmap error\n");
- exit(-1);
- }
+ if (ss.ss_sp == (void *)-1) {
+ perror("mmap error\n");
+ exit(-1);
+ }
- /* Force the allocation through a page fault */
- if (madvise(ss.ss_sp, SIGSTKSZ, MADV_DONTNEED)) {
- perror("madvise\n");
- exit(-1);
- }
+ /* Force the allocation through a page fault */
+ if (madvise(ss.ss_sp, SIGSTKSZ, MADV_DONTNEED)) {
+ perror("madvise\n");
+ exit(-1);
+ }
- /* Setting an alternative stack to generate a page fault when
- * the signal is raised.
- */
- if (sigaltstack(&ss, NULL)) {
- perror("sigaltstack\n");
- exit(-1);
+ /*
+ * Setting an alternative stack to generate a page fault when
+ * the signal is raised.
+ */
+ if (sigaltstack(&ss, NULL)) {
+ perror("sigaltstack\n");
+ exit(-1);
+ }
+
+ /* The signal handler will enable MSR_TS */
+ sigaction(SIGUSR1, &usr_sa, NULL);
+ /* If it does not crash, it might segfault, avoid it to retest */
+ sigaction(SIGSEGV, &seg_sa, NULL);
+
+ raise(SIGUSR1);
+ count++;
}
-
- /* The signal handler will enable MSR_TS */
- sigaction(SIGUSR1, &usr_sa, NULL);
- /* If it does not crash, it will segfault, avoid it to retest */
- sigaction(SIGSEGV, &seg_sa, NULL);
-
- raise(SIGUSR1);
}
int tm_signal_context_force_tm(void)
@@ -169,11 +169,7 @@ int tm_signal_context_force_tm(void)
*/
SKIP_IF(!is_ppc64le());
- /* Will get back here after COUNT_MAX interactions */
- getcontext(&main_context);
-
- if (!first_time++)
- tm_trap_test();
+ tm_trap_test();
return EXIT_SUCCESS;
}