From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Dexuan Cui <decui@microsoft.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
linux-mm@kvack.org, olaf@aepfle.de, apw@canonical.com,
jasowang@redhat.com, dave.hansen@intel.com, riel@redhat.com,
Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH 3.14 035/203] x86, pageattr: Prevent overflow in slow_virt_to_phys() for X86_PAE
Date: Wed, 12 Nov 2014 10:15:05 +0900 [thread overview]
Message-ID: <20141112011544.326707411@linuxfoundation.org> (raw)
In-Reply-To: <20141112011542.686743533@linuxfoundation.org>
3.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dexuan Cui <decui@microsoft.com>
commit d1cd1210834649ce1ca6bafe5ac25d2f40331343 upstream.
pte_pfn() returns a PFN of long (32 bits in 32-PAE), so "long <<
PAGE_SHIFT" will overflow for PFNs above 4GB.
Due to this issue, some Linux 32-PAE distros, running as guests on Hyper-V,
with 5GB memory assigned, can't load the netvsc driver successfully and
hence the synthetic network device can't work (we can use the kernel parameter
mem=3000M to work around the issue).
Cast pte_pfn() to phys_addr_t before shifting.
Fixes: "commit d76565344512: x86, mm: Create slow_virt_to_phys()"
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: gregkh@linuxfoundation.org
Cc: linux-mm@kvack.org
Cc: olaf@aepfle.de
Cc: apw@canonical.com
Cc: jasowang@redhat.com
Cc: dave.hansen@intel.com
Cc: riel@redhat.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1414580017-27444-1-git-send-email-decui@microsoft.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/mm/pageattr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -405,7 +405,7 @@ phys_addr_t slow_virt_to_phys(void *__vi
psize = page_level_size(level);
pmask = page_level_mask(level);
offset = virt_addr & ~pmask;
- phys_addr = pte_pfn(*pte) << PAGE_SHIFT;
+ phys_addr = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT;
return (phys_addr | offset);
}
EXPORT_SYMBOL_GPL(slow_virt_to_phys);
--
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parent reply other threads:[~2014-11-12 1:38 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <20141112011542.686743533@linuxfoundation.org>]
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