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authorDexuan Cui <decui@microsoft.com>2014-10-29 13:53:37 +0300
committerThomas Gleixner <tglx@linutronix.de>2014-10-29 12:57:21 +0300
commitd1cd1210834649ce1ca6bafe5ac25d2f40331343 (patch)
tree65b33c4cd4408e03045e6111dd17a94b3ed49f38 /arch
parentb77e8f435337baa1cd15852fb9db3f6d26cd8eb7 (diff)
downloadlinux-d1cd1210834649ce1ca6bafe5ac25d2f40331343.tar.xz
x86, pageattr: Prevent overflow in slow_virt_to_phys() for X86_PAE
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/mm/pageattr.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index ae242a7c11c7..36de293caf25 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -409,7 +409,7 @@ phys_addr_t slow_virt_to_phys(void *__virt_addr)
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);