Merge tag 'trace-v5.17-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

67bfce0e · Linus Torvalds <[email protected]> · 2022-01-23 08:07:02 +02:00

Pull ftrace fix from Steven Rostedt:
 "Fix s390 breakage from sorting mcount tables.

  The latest merge of the tracing tree sorts the mcount table at build
  time. But s390 appears to do things differently (like always) and
  replaces the sorted table back to the original unsorted one. As the
  ftrace algorithm depends on it being sorted, bad things happen when it
  is not, and s390 experienced those bad things.

  Add a new config to tell the boot if the mcount table is sorted or
  not, and allow s390 to opt out of it"

* tag 'trace-v5.17-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Fix assuming build time sort works for s390

Commit: 67bfce0e01927859618b76ff5a36a7f23b412cef
Parents: 473aec0e · 6b9b6413

Merge commit. Changes below are compared with the first parent: 473aec0e.

Changes

2 files changed · +10 −3

File	Status	Add	Del	Content
kernel/trace/Kconfig	modified	+8	−1	View file
kernel/trace/ftrace.c	modified	+2	−2	View file

kernel/trace/Kconfig

View file

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index f468767..752ed89 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

kernel/trace/ftrace.c

View file

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 6163b6f..f9feb19 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -6435,10 +6435,10 @@ 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 {