On Fri, 21 Jan 2022 11:42:28 +0100
Heiko Carstens <hca@xxxxxxxxxxxxx> wrote:
> This really should be addressed before rc1 is out, otherwise s390 is
> broken if somebody enables ftrace.
> Where "broken" translates to random crashes as soon as ftrace is
> enabled, which again is nowadays quite common.
Instead of reverting, should we just add this patch?
-- Steve
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index f468767bc287..752ed89a293b 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -70,6 +70,13 @@ config HAVE_C_RECORDMCOUNT
help
C version of recordmcount available?
+config BUILDTIME_MCOUNT_SORT
+ bool
+ default y
+ depends on BUILDTIME_TABLE_SORT && !S390
+ help
+ Sort the mcount_loc section at build time.
+
config TRACER_MAX_TRACE
bool
@@ -918,7 +925,7 @@ config EVENT_TRACE_TEST_SYSCALLS
config FTRACE_SORT_STARTUP_TEST
bool "Verify compile time sorting of ftrace functions"
depends on DYNAMIC_FTRACE
- depends on BUILDTIME_TABLE_SORT
+ depends on BUILDTIME_MCOUNT_SORT
help
Sorting of the mcount_loc sections that is used to find the
where the ftrace knows where to patch functions for tracing
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 403e485bf091..b01e1fa62193 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -6429,10 +6429,10 @@ static int ftrace_process_locs(struct module *mod,
/*
* Sorting mcount in vmlinux at build time depend on
- * CONFIG_BUILDTIME_TABLE_SORT, while mcount loc in
+ * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
* modules can not be sorted at build time.
*/
- if (!IS_ENABLED(CONFIG_BUILDTIME_TABLE_SORT) || mod) {
+ if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
sort(start, count, sizeof(*start),
ftrace_cmp_ips, NULL);
} else {
