Re: [discuss] 2.6.19-rc6: known regressions (v4)

[Andi Kleen <ak@suse.de>]

On Wed, Nov 22, 2006 at 05:05:49PM +0100, Andre Noll wrote:
> Unfortunately, yes. I tried rc6, current git, and currrent git + David
> Rientjes' patch. They all show the same behaviour.

I must have missed that patch.
> 
> > It's probably another bug in the memmap parsing rewrite (Mel cc'ed) 
> > but the debugging information in the standard kernel unfortunately
> > doesn't give enough output to find out where it happens.
> 
> Feel free to send me a debugging patch..

Here's one. Please send output (unless Mel finds the problem first..)

-Andi

Index: linux-2.6.19-rc6-hack/mm/page_alloc.c
===================================================================
--- linux-2.6.19-rc6-hack/mm/page_alloc.c
+++ linux-2.6.19-rc6-hack/mm/page_alloc.c
@@ -188,6 +188,10 @@ static inline int bad_range(struct zone 
 
 static void bad_page(struct page *page)
 {
+	static int warned; 
+	if (!warned) { 
+	warned = 1;
+	printk(KERN_EMERG "page address %lx\n", page_address(page));
 	printk(KERN_EMERG "Bad page state in process '%s'\n"
 		KERN_EMERG "page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n"
 		KERN_EMERG "Trying to fix it up, but a reboot is needed\n"
@@ -196,6 +200,7 @@ static void bad_page(struct page *page)
 		(unsigned long)page->flags, page->mapping,
 		page_mapcount(page), page_count(page));
 	dump_stack();
+	}
 	page->flags &= ~(1 << PG_lru	|
 			1 << PG_private |
 			1 << PG_locked	|