rpms/kernel/devel linux-2.6-vm-debug.patch, NONE, 1.1 kernel-2.6.spec, 1.1821, 1.1822

[fedora-cvs-commits at redhat.com]

Author: davej

Update of /cvs/dist/rpms/kernel/devel
In directory cvs.devel.redhat.com:/tmp/cvs-serv8626

Modified Files:
	kernel-2.6.spec 
Added Files:
	linux-2.6-vm-debug.patch 
Log Message:
some more debug info about the pagecount going negative.


linux-2.6-vm-debug.patch:
 drivers/scsi/st.c  |    1 +
 include/linux/mm.h |    1 +
 mm/rmap.c          |    7 +++++++
 3 files changed, 9 insertions(+)

--- NEW FILE linux-2.6-vm-debug.patch ---
--- linux-2.6.15/mm/rmap.c~	2006-01-03 08:53:32.000000000 -0500
+++ linux-2.6.15/mm/rmap.c	2006-01-03 08:58:19.000000000 -0500
@@ -484,6 +484,13 @@ void page_remove_rmap(struct page *page)
 	BUG_ON(PageReserved(page));
 
 	if (atomic_add_negative(-1, &page->_mapcount)) {
+		if (page_mapcount(page) < 0) {
+			printk (KERN_EMERG "Eeek! page_mapcount(page) went negative! (%d)\n", page_mapcount(page));
+			printk (KERN_EMERG "  page->flags = %lx\n", page->flags);
+			printk (KERN_EMERG "  page->count = %x\n", page_count(page));
+			printk (KERN_EMERG "  page->mapping = %p\n", page->mapping);
+		}
+		
 		BUG_ON(page_mapcount(page) < 0);
 		/*
 		 * It would be tidy to reset the PageAnon mapping here,
--- linux-2.6.15/drivers/scsi/st.c~	2006-01-05 21:58:31.000000000 -0500
+++ linux-2.6.15/drivers/scsi/st.c	2006-01-05 21:59:31.000000000 -0500
@@ -4508,6 +4508,7 @@ static int sgl_unmap_user_pages(struct s
 	for (i=0; i < nr_pages; i++) {
 		struct page *page = sgl[i].page;
 
+		sgl[i].page = NULL;
 		if (dirtied)
 			SetPageDirty(page);
 		/* FIXME: cache flush missing for rw==READ
--- linux-2.6.15/include/linux/mm.h~	2006-01-05 22:02:20.000000000 -0500
+++ linux-2.6.15/include/linux/mm.h	2006-01-05 22:02:48.000000000 -0500
@@ -299,6 +299,7 @@ struct page {
 #define put_page_testzero(p)				\
 	({						\
 		BUG_ON(page_count(p) == 0);		\
+		BUG_ON(page_count(p) <= page_mapcount(p));	\
 		atomic_add_negative(-1, &(p)->_count);	\
 	})
 


Index: kernel-2.6.spec
===================================================================
RCS file: /cvs/dist/rpms/kernel/devel/kernel-2.6.spec,v
retrieving revision 1.1821
retrieving revision 1.1822
diff -u -r1.1821 -r1.1822
--- kernel-2.6.spec	5 Jan 2006 11:02:08 -0000	1.1821
+++ kernel-2.6.spec	6 Jan 2006 03:15:23 -0000	1.1822
@@ -374,6 +374,7 @@
 # VM bits.
 Patch2000: linux-2.6-vm-oomkiller-debugging.patch
 Patch2001: linux-2.6-vm-silence-atomic-alloc-failures.patch
+Patch2002: linux-2.6-vm-debug.patch
 
 # Broadcom wireless driver
 Patch5000: linux-2.6-bcm43xx.patch
@@ -876,6 +877,8 @@
 %patch2000 -p1
 # Silence GFP_ATOMIC failures.
 %patch2001 -p1
+# Try to trace some negative pagecount errors.
+%patch2002 -p1
 
 #
 # Patches 5000 to 6000 are reserved for new drivers that are about to
@@ -1391,6 +1394,9 @@
 %endif
 
 %changelog
+* Thu Jan  5 2006 Dave Jones <davej at redhat.com>
+- Try to debug some negative pagecount errors.
+
 * Tue Jan  3 2006 Dave Jones <davej at redhat.com>
 - Silence some gcc4.1 warnings.