Re: [PATCH] intel-agp.c: Fix crash when accessing nonexistent GTT entries in i915

From: Andrew Morton
Date: Wed Mar 24 2010 - 14:15:51 EST


On Tue, 23 Mar 2010 12:40:05 +0100
Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx> wrote:

> On Tue, Mar 23, 2010 at 5:14 AM, Christian Kujau <lists@xxxxxxxxxxxxxxx> wrote:
> > On Mon, 22 Mar 2010 at 20:57, Andrew Morton wrote:
> >> On Sun, 21 Mar 2010 16:30:20 +0100 Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx> wrote:
> >> > I bisected in order to find the commit 5877960869333e42ebeb733e8d9d5630ff96d350.
> >
> > I believe this[0] is fc61901373987ad61851ed001fe971f3ee8d96a3 upstream:
>
> Indeed. Also in
>
> http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.32.y.git;a=commit;h=fc61901373987ad61851ed001fe971f3ee8d96a3

Does reverting that patch from the current code fix the crash?

--- a/drivers/char/agp/intel-agp.c~revert-1
+++ a/drivers/char/agp/intel-agp.c
@@ -207,7 +207,6 @@ static struct _intel_private {
* popup and for the GTT.
*/
int gtt_entries; /* i830+ */
- int gtt_total_size;
union {
void __iomem *i9xx_flush_page;
void *i8xx_flush_page;
@@ -1239,7 +1238,7 @@ static int intel_i915_configure(void)
readl(intel_private.registers+I810_PGETBL_CTL); /* PCI Posting. */

if (agp_bridge->driver->needs_scratch_page) {
- for (i = intel_private.gtt_entries; i < intel_private.gtt_total_size; i++) {
+ for (i = intel_private.gtt_entries; i < current_size->num_entries; i++) {
writel(agp_bridge->scratch_page, intel_private.gtt+i);
}
readl(intel_private.gtt+i-1); /* PCI Posting. */
@@ -1394,8 +1393,6 @@ static int intel_i915_create_gatt_table(
if (!intel_private.gtt)
return -ENOMEM;

- intel_private.gtt_total_size = gtt_map_size / 4;
-
temp &= 0xfff80000;

intel_private.registers = ioremap(temp, 128 * 4096);
@@ -1485,8 +1482,6 @@ static int intel_i965_create_gatt_table(
if (!intel_private.gtt)
return -ENOMEM;

- intel_private.gtt_total_size = gtt_size / 4;
-
intel_private.registers = ioremap(temp, 128 * 4096);
if (!intel_private.registers) {
iounmap(intel_private.gtt);
_

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