Re: 2.6.26-rc5-mm3

From: Daniel Walker
Date: Wed Jun 18 2008 - 13:56:30 EST



On Fri, 2008-06-13 at 00:32 +0100, Byron Bradley wrote:
> Looks like x86 and ARM both fail to boot if PROFILE_LIKELY, FTRACE and
> DYNAMIC_FTRACE are selected. If any one of those three are disabled it
> boots (or fails in some other way which I'm looking at now). The serial
> console output from both machines when they fail to boot is below, let me
> know if there is any other information I can provide.

I was able to reproduce a hang on x86 with those options. The patch
below is a potential fix. I think we don't want to trace
do_check_likely(), since the ftrace internals might use likely/unlikely
macro's which will just cause recursion back to do_check_likely()..

Signed-off-by: Daniel Walker <dwalker@xxxxxxxxxx>

---
lib/likely_prof.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6.25/lib/likely_prof.c
===================================================================
--- linux-2.6.25.orig/lib/likely_prof.c
+++ linux-2.6.25/lib/likely_prof.c
@@ -22,7 +22,7 @@

static struct likeliness *likeliness_head;

-int do_check_likely(struct likeliness *likeliness, unsigned int ret)
+int notrace do_check_likely(struct likeliness *likeliness, unsigned int ret)
{
static unsigned long likely_lock;



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