linux-kernel - Re: hpwdt oops in clflush_cache

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Message-ID: <20080227211414.GA12199@elte.hu>
Date:	Wed, 27 Feb 2008 22:14:14 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	Roland Dreier <rdreier@...co.com>, linux-kernel@...r.kernel.org,
	Thomas Mingarelli <thomas.mingarelli@...com>
Subject: Re: hpwdt oops in clflush_cache_range


* Thomas Gleixner <tglx@...utronix.de> wrote:

> On Wed, 27 Feb 2008, Thomas Gleixner wrote:
> > +static inline int phys_addr_valid(unsigned long addr)
> > +{
> > +	return addr < (1 << boot_cpu_data.x86_phys_bits);
> 
> That needs to be:
> 
> +     return addr < (1UL << boot_cpu_data.x86_phys_bits);
> 
> Where is my brown paperbag ? I know that GCC _is_ stupid, but I never 
> remember.

here's the updated patch.

	Ingo

-------------->
Subject: x86: check physical address range in ioremap
From: Thomas Gleixner <tglx@...utronix.de>
Date: Wed, 27 Feb 2008 20:57:40 +0100

Roland Dreier reported in http://lkml.org/lkml/2008/2/27/194

[ 8425.915139] BUG: unable to handle kernel paging request at ffffc20001a0a000
[ 8425.919087] IP: [<ffffffff8021dacc>] clflush_cache_range+0xc/0x25
[ 8425.919087] PGD 1bf80e067 PUD 1bf80f067 PMD 1bb497067 PTE 80000047000ee17b

This is on a Intel machine with 36bit physical address space. The PTE
entry references 47000ee000, which is outside of it.

Add a check for the physical address space and warn/printk about the
stupid caller.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 arch/x86/mm/ioremap.c |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

Index: linux-x86.q/arch/x86/mm/ioremap.c
===================================================================
--- linux-x86.q.orig/arch/x86/mm/ioremap.c
+++ linux-x86.q/arch/x86/mm/ioremap.c
@@ -35,6 +35,18 @@ unsigned long __phys_addr(unsigned long 
 }
 EXPORT_SYMBOL(__phys_addr);
 
+static inline int phys_addr_valid(unsigned long addr)
+{
+	return addr < (1UL << boot_cpu_data.x86_phys_bits);
+}
+
+#else
+
+static inline int phys_addr_valid(unsigned long addr)
+{
+	return 1;
+}
+
 #endif
 
 int page_is_ram(unsigned long pagenr)
@@ -118,6 +130,13 @@ static void __iomem *__ioremap(unsigned 
 	if (!size || last_addr < phys_addr)
 		return NULL;
 
+	if (!phys_addr_valid(phys_addr)) {
+		printk(KERN_WARNING "ioremap: invalid physical address %lx\n",
+		       phys_addr);
+		WARN_ON_ONCE(1);
+		return NULL;
+	}
+
 	/*
 	 * Don't remap the low PCI/ISA area, it's always mapped..
 	 */
--
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