This must be brown paper bag week for Steven Rostedt!
While working on ftrace for PPC, I discovered that the hash locking done
when CONFIG_FTRACE_MCOUNT_RECORD is not set, is totally incorrect.
With a cut and paste error, I had the hash lock macro to lock for both
hash_lock _and_ hash_unlock!
This bug did not affect x86 since this bug was introduced when
CONFIG_FTRACE_MCOUNT_RECORD was added to x86.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
---
kernel/trace/ftrace.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
Index: linux-tip.git/kernel/trace/ftrace.c
===================================================================
--- linux-tip.git.orig/kernel/trace/ftrace.c 2008-09-05 21:53:46.000000000 -0700
+++ linux-tip.git/kernel/trace/ftrace.c 2008-09-05 21:57:57.000000000 -0700
@@ -170,7 +170,8 @@ static int __unregister_ftrace_function(
*/
static DEFINE_SPINLOCK(ftrace_hash_lock);
#define ftrace_hash_lock(flags) spin_lock_irqsave(&ftrace_hash_lock, flags)
-#define ftrace_hash_unlock(flags) spin_lock_irqsave(&ftrace_hash_lock, flags)
+#define ftrace_hash_unlock(flags) \
+ spin_unlock_irqrestore(&ftrace_hash_lock, flags)
#else
/* This is protected via the ftrace_lock with MCOUNT_RECORD. */
#define ftrace_hash_lock(flags) do { (void)(flags); } while (0)
--
--
