Commit-ID: d1cd1210834649ce1ca6bafe5ac25d2f40331343 Gitweb: http://git.kernel.org/tip/d1cd1210834649ce1ca6bafe5ac25d2f40331343 Author: Dexuan Cui <de...@microsoft.com> AuthorDate: Wed, 29 Oct 2014 03:53:37 -0700 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Wed, 29 Oct 2014 10:57:21 +0100
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 <de...@microsoft.com> Cc: K. Y. Srinivasan <k...@microsoft.com> Cc: Haiyang Zhang <haiya...@microsoft.com> Cc: gre...@linuxfoundation.org Cc: linux...@kvack.org Cc: o...@aepfle.de Cc: a...@canonical.com Cc: jasow...@redhat.com Cc: dave.han...@intel.com Cc: r...@redhat.com Cc: sta...@vger.kernel.org Link: http://lkml.kernel.org/r/1414580017-27444-1-git-send-email-de...@microsoft.com Signed-off-by: Thomas Gleixner <t...@linutronix.de> --- arch/x86/mm/pageattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index ae242a7..36de293 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); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
