rpms/kernel/devel linux-2.6-vm-set_page_dirty_buffers-oops.patch, NONE, 1.1 kernel-2.6.spec, 1.2757, 1.2758

Tue Oct 10 20:45:10 UTC 2006

Author: davej

Update of /cvs/dist/rpms/kernel/devel
In directory cvs.devel.redhat.com:/tmp/cvs-serv10417

Modified Files:
	kernel-2.6.spec 
Added Files:
	linux-2.6-vm-set_page_dirty_buffers-oops.patch 
Log Message:
Fix bug in set_page_dirty_buffers

linux-2.6-vm-set_page_dirty_buffers-oops.patch:
 buffer.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletion(-)

--- NEW FILE linux-2.6-vm-set_page_dirty_buffers-oops.patch ---
>From davej  Mon Oct  9 22:38:37 2006
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Date: 	Tue, 10 Oct 2006 04:36:54 +0200
From: Nick Piggin <npiggin at suse.de>
To: Andrew Morton <akpm at osdl.org>, Linus Torvalds <torvalds at osdl.org>,
        Peter Zijlstra <a.p.zijlstra at chello.nl>,
        Linux Memory Management List <linux-mm at kvack.org>
Cc: Greg KH <gregkh at suse.de>
Subject: [patch] mm: bug in set_page_dirty_buffers
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This was triggered, but not the fault of, the dirty page accounting
patches. Suitable for -stable as well, after it goes upstream.

Unable to handle kernel NULL pointer dereference at virtual address 0000004c
EIP is at _spin_lock+0x12/0x66
Call Trace:
 [<401766e7>] __set_page_dirty_buffers+0x15/0xc0
 [<401401e7>] set_page_dirty+0x2c/0x51
 [<40140db2>] set_page_dirty_balance+0xb/0x3b
 [<40145d29>] __do_fault+0x1d8/0x279
 [<40147059>] __handle_mm_fault+0x125/0x951
 [<401133f1>] do_page_fault+0x440/0x59f
 [<4034d0c1>] error_code+0x39/0x40
 [<08048a33>] 0x8048a33
 =======================

Signed-off-by: Nick Piggin <npiggin at suse.de>

Index: linux-2.6/fs/buffer.c
===================================================================
--- linux-2.6.orig/fs/buffer.c
+++ linux-2.6/fs/buffer.c
@@ -701,7 +701,10 @@ EXPORT_SYMBOL(mark_buffer_dirty_inode);
  */
 int __set_page_dirty_buffers(struct page *page)
 {
-	struct address_space * const mapping = page->mapping;
+	struct address_space * const mapping = page_mapping(page);
+
+	if (unlikely(!mapping))
+		return !TestSetPageDirty(page);
 
 	spin_lock(&mapping->private_lock);
 	if (page_has_buffers(page)) {

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Index: kernel-2.6.spec
===================================================================
RCS file: /cvs/dist/rpms/kernel/devel/kernel-2.6.spec,v
retrieving revision 1.2757
retrieving revision 1.2758
diff -u -r1.2757 -r1.2758
--- kernel-2.6.spec	10 Oct 2006 19:56:16 -0000	1.2757
+++ kernel-2.6.spec	10 Oct 2006 20:45:08 -0000	1.2758
@@ -522,6 +522,7 @@
 Patch2003: linux-2.6-vm-pagecnt.patch
 Patch2004: linux-2.6-vm-icp2-nonzero-gfp.patch
 Patch2005: linux-2.6-mm-prevent-oom-fixes.patch
+Patch2006: linux-2.6-vm-set_page_dirty_buffers-oops.patch
 
 # Tweak some defaults.
 Patch2100: linux-2.6-defaults-fat-utf8.patch
@@ -1170,6 +1171,8 @@
 %patch2004 -p1
 # OOM killer enhancements.
 %patch2005 -p1
+# Fix bug in set_page_dirty_buffers
+%patch2006 -p1
 
 # Changes to upstream defaults.
 # Use UTF-8 by default on VFAT.
@@ -2001,6 +2004,7 @@
 %changelog
 * Tue Oct 10 2006 Dave Jones <davej at redhat.com>
 - OOM Killer improvements.
+- Fix bug in set_page_dirty_buffers
 
 * Tue Oct 10 2006 Jon Masters <jcm at redhat.com>
 - Move symsets into /usr/src/kernels.


