ttm_get_pages() will OOPS with highmem allocation

Commit Message

Jonathan Morton Nov. 16, 2012, 5:19 p.m. UTC

Reposting from this kernel bug:
https://bugzilla.kernel.org/show_bug.cgi?id=50241

I've tested the patch and it solves a highly repeatable OOPS with the
CedarView driver that I'm porting.

Reviewed-by: Thomas Hellstrom <[e-mail]>

From 3552913d3a1c2d3c4ce158e91dc18cd12b522cb2 Mon Sep 17 00:00:00 2001
From: Yakui Zhao <[e-mail]>
Date: Tue, 7 Feb 2012 15:33:13 -0500
Subject: [PATCH] Clear the ttm page allocated from high memory zone
correctly

The TTM page can be allocated from high memory. In such case it is
wrong to use the page_address(page) as the virtual address for the high
memory page.

Signed-off-by: Zhao Yakui <[e-mail]>
---
 drivers/gpu/drm/ttm/ttm_page_alloc.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

Comments

Greg KH Nov. 16, 2012, 5:32 p.m. UTC | #1

On Fri, Nov 16, 2012 at 07:19:01PM +0200, Jonathan Morton wrote:
> Reposting from this kernel bug:
> https://bugzilla.kernel.org/show_bug.cgi?id=50241
> 
> I've tested the patch and it solves a highly repeatable OOPS with the
> CedarView driver that I'm porting.
> 
> Reviewed-by: Thomas Hellstrom <[e-mail]>

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read Documentation/stable_kernel_rules.txt
for how to do this properly.

</formletter>

Patch

diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c
b/drivers/gpu/drm/ttm/ttm_page_alloc.c index d948575..df976d9 100644
--- a/drivers/gpu/drm/ttm/ttm_page_alloc.c
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c
@@ -708,7 +708,10 @@  int ttm_get_pages(struct list_head *pages, int
flags, /* clear the pages coming from the pool if requested */
 	if (flags & TTM_PAGE_FLAG_ZERO_ALLOC) {
 		list_for_each_entry(p, pages, lru) {
-			clear_page(page_address(p));
+			if (PageHighMem(p))
+				clear_highpage(p);
+			else
+				clear_page(page_address(p));
 		}
 	}