This is a note to let you know that I've just added the patch titled
genirq: Prevent access beyond allocated_irqs bitmap
to the 2.6.37-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
genirq-prevent-access-beyond-allocated_irqs-bitmap.patch
and it can be found in the queue-2.6.37 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From c1ee6264280e740a9d3ff3feef38642cf0a57013 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <[email protected]>
Date: Thu, 17 Feb 2011 17:45:15 +0100
Subject: genirq: Prevent access beyond allocated_irqs bitmap
From: Thomas Gleixner <[email protected]>
commit c1ee6264280e740a9d3ff3feef38642cf0a57013 upstream.
Lars-Peter Clausen pointed out:
I stumbled upon this while looking through the existing archs using
SPARSE_IRQ. Even with SPARSE_IRQ the NR_IRQS is still the upper
limit for the number of IRQs.
Both PXA and MMP set NR_IRQS to IRQ_BOARD_START, with
IRQ_BOARD_START being the number of IRQs used by the core.
In various machine files the nr_irqs field of the ARM machine
defintion struct is then set to "IRQ_BOARD_START + NR_BOARD_IRQS".
As a result "nr_irqs" will greater then NR_IRQS which then again
causes the "allocated_irqs" bitmap in the core irq code to be
accessed beyond its size overwriting unrelated data.
The core code really misses a sanity check there.
This went unnoticed so far as by chance the compiler/linker places
data behind that bitmap which gets initialized later on those affected
platforms.
So the obvious fix would be to add a sanity check in early_irq_init()
and break all affected platforms. Though that check wants to be
backported to stable as well, which will require to fix all known
problematic platforms and probably some more yet not known ones as
well. Lots of churn.
A way simpler solution is to allocate a slightly larger bitmap and
avoid the whole churn w/o breaking anything. Add a few warnings when
an arch returns utter crap.
Reported-by: Lars-Peter Clausen <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: Haojian Zhuang <[email protected]>
Cc: Eric Miao <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
kernel/irq/internals.h | 6 ++++++
kernel/irq/irqdesc.c | 11 ++++++++++-
kernel/irq/resend.c | 2 +-
3 files changed, 17 insertions(+), 2 deletions(-)
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -3,6 +3,12 @@
*/
#include <linux/irqdesc.h>
+#ifdef CONFIG_SPARSE_IRQ
+# define IRQ_BITMAP_BITS (NR_IRQS + 8196)
+#else
+# define IRQ_BITMAP_BITS NR_IRQS
+#endif
+
extern int noirqdebug;
#define irq_data_to_desc(data) container_of(data, struct irq_desc, irq_data)
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -91,7 +91,7 @@ int nr_irqs = NR_IRQS;
EXPORT_SYMBOL_GPL(nr_irqs);
static DEFINE_MUTEX(sparse_irq_lock);
-static DECLARE_BITMAP(allocated_irqs, NR_IRQS);
+static DECLARE_BITMAP(allocated_irqs, IRQ_BITMAP_BITS);
#ifdef CONFIG_SPARSE_IRQ
@@ -215,6 +215,15 @@ int __init early_irq_init(void)
initcnt = arch_probe_nr_irqs();
printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d %d\n", NR_IRQS, nr_irqs,
initcnt);
+ if (WARN_ON(nr_irqs > IRQ_BITMAP_BITS))
+ nr_irqs = IRQ_BITMAP_BITS;
+
+ if (WARN_ON(initcnt > IRQ_BITMAP_BITS))
+ initcnt = IRQ_BITMAP_BITS;
+
+ if (initcnt > nr_irqs)
+ nr_irqs = initcnt;
+
for (i = 0; i < initcnt; i++) {
desc = alloc_desc(i, node);
set_bit(i, allocated_irqs);
--- a/kernel/irq/resend.c
+++ b/kernel/irq/resend.c
@@ -23,7 +23,7 @@
#ifdef CONFIG_HARDIRQS_SW_RESEND
/* Bitmap to handle software resend of interrupts: */
-static DECLARE_BITMAP(irqs_resend, NR_IRQS);
+static DECLARE_BITMAP(irqs_resend, IRQ_BITMAP_BITS);
/*
* Run software resends of IRQ's
Patches currently in stable-queue which might be from [email protected] are
queue-2.6.37/genirq-disable-the-shirq_debug-call-in-request_threaded_irq-for-now.patch
queue-2.6.37/genirq-prevent-access-beyond-allocated_irqs-bitmap.patch
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