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authorLinus Torvalds <torvalds@linux-foundation.org>2016-11-15 08:49:13 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-11-15 08:49:13 -0800
commit81bcfe5e48f9b8c42cf547f1c74c7f60c44c34c8 (patch)
tree55f6ce31dbb95c967fa19c508ccebeb02a16a1d9 /kernel
parent80fc2f7fd8dece7bfa9b5b5dafb8705bbcefa6b4 (diff)
parent546fece4eae871f033925ccf0ff2b740725ae915 (diff)
Merge tag 'trace-v4.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt: "Alexei discovered a race condition in modules failing to load that can cause a ftrace check to trigger and disable ftrace. This is because of the way modules are registered to ftrace. Their functions are loaded in the ftrace function tables but set to "disabled" since they are still in the process of being loaded by the module. After the module is finished, it calls back into the ftrace infrastructure to enable it. Looking deeper into the locations that access all the functions in the table, I found more locations that should ignore the disabled ones" * tag 'trace-v4.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ftrace: Add more checks for FTRACE_FL_DISABLED in processing ip records ftrace: Ignore FTRACE_FL_DISABLED while walking dyn_ftrace records
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/ftrace.c24
1 files changed, 23 insertions, 1 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 2050a7652a86..da87b3cba5b3 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1862,6 +1862,10 @@ static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
/* Update rec->flags */
do_for_each_ftrace_rec(pg, rec) {
+
+ if (rec->flags & FTRACE_FL_DISABLED)
+ continue;
+
/* We need to update only differences of filter_hash */
in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
@@ -1884,6 +1888,10 @@ rollback:
/* Roll back what we did above */
do_for_each_ftrace_rec(pg, rec) {
+
+ if (rec->flags & FTRACE_FL_DISABLED)
+ continue;
+
if (rec == end)
goto err_out;
@@ -2397,6 +2405,10 @@ void __weak ftrace_replace_code(int enable)
return;
do_for_each_ftrace_rec(pg, rec) {
+
+ if (rec->flags & FTRACE_FL_DISABLED)
+ continue;
+
failed = __ftrace_replace_code(rec, enable);
if (failed) {
ftrace_bug(failed, rec);
@@ -2763,7 +2775,7 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
struct dyn_ftrace *rec;
do_for_each_ftrace_rec(pg, rec) {
- if (FTRACE_WARN_ON_ONCE(rec->flags))
+ if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
pr_warn(" %pS flags:%lx\n",
(void *)rec->ip, rec->flags);
} while_for_each_ftrace_rec();
@@ -3598,6 +3610,10 @@ match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
goto out_unlock;
do_for_each_ftrace_rec(pg, rec) {
+
+ if (rec->flags & FTRACE_FL_DISABLED)
+ continue;
+
if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
ret = enter_record(hash, rec, clear_filter);
if (ret < 0) {
@@ -3793,6 +3809,9 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
do_for_each_ftrace_rec(pg, rec) {
+ if (rec->flags & FTRACE_FL_DISABLED)
+ continue;
+
if (!ftrace_match_record(rec, &func_g, NULL, 0))
continue;
@@ -4685,6 +4704,9 @@ ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer)
do_for_each_ftrace_rec(pg, rec) {
+ if (rec->flags & FTRACE_FL_DISABLED)
+ continue;
+
if (ftrace_match_record(rec, &func_g, NULL, 0)) {
/* if it is in the array */
exists = false;