Attachment 580291 Details for Bug 816365 – An (untested) proposed approach to addressing the symptom without addressing the cause.

[patch] An (untested) proposed approach to addressing the symptom without addressing the cause.

swap_cgroup_invalid_pte.diff (text/plain), 970 bytes, created by Brian Bockelman on 2012-04-25 21:42:22 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Brian Bockelman

Created: 2012-04-25 21:42:22 UTC

Size: 970 bytes

patch

obsolete

>--- mm/page_cgroup.c.orig	2012-04-25 13:45:13.502843598 -0500
>+++ mm/page_cgroup.c	2012-04-25 16:37:06.711837614 -0500
>@@ -10,6 +10,8 @@
> #include <linux/cgroup.h>
> #include <linux/swapops.h>
> 
>+static unsigned int max_valid_type = 0;
>+
> static void __meminit init_page_cgroup(struct page_cgroup *pc, unsigned long id)
> {
> 	pc->flags = 0;
>@@ -484,7 +486,15 @@
> 	struct swap_cgroup *sc;
> 	unsigned short ret;
> 
>+	// Protect against an invalid PTE
>+	if (type > nr_swapfiles)
>+		return 0;
>+
> 	ctrl = &swap_cgroup_ctrl[type];
>+
>+	if (!ctrl->map)
>+		return 0;
>+
> 	mappage = ctrl->map[idx];
> 	sc = page_address(mappage);
> 	sc += pos;
>@@ -512,6 +522,12 @@
> 	memset(array, 0, array_size);
> 	ctrl = &swap_cgroup_ctrl[type];
> 	mutex_lock(&swap_cgroup_mutex);
>+
>+	/* Track the maximum swap type encountered,
>+	 * to try and avoid bad PTE bugs. */
>+	if (type > max_valid_type)
>+		max_valid_type = type;
>+
> 	ctrl->length = length;
> 	ctrl->map = array;
> 	spin_lock_init(&ctrl->lock);

Actions: View | Diff

Attachments on bug 816365: 580291