From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Beulich , Andy Lutomirski , Andy Lutomirski , Boris Ostrovsky , Borislav Petkov , Brian Gerst , David Vrabel , Denys Vlasenko , "H. Peter Anvin" , Konrad Rzeszutek Wilk , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Sasha Levin Subject: [PATCH 3.18 115/144] x86/ldt: Fix small LDT allocation for Xen Date: Thu, 8 Nov 2018 13:51:26 -0800 Message-Id: <20181108215106.300920029@linuxfoundation.org> In-Reply-To: <20181108215054.826084593@linuxfoundation.org> References: <20181108215054.826084593@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit f454b478861325f067fd58ba7ee9f1b5c4a9d6a0 ] While the following commit: 37868fe113 ("x86/ldt: Make modify_ldt synchronous") added a nice comment explaining that Xen needs page-aligned whole page chunks for guest descriptor tables, it then nevertheless used kzalloc() on the small size path. As I'm unaware of guarantees for kmalloc(PAGE_SIZE, ) to return page-aligned memory blocks, I believe this needs to be switched back to __get_free_page() (or better get_zeroed_page()). Signed-off-by: Jan Beulich Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: David Vrabel Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Konrad Rzeszutek Wilk Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/55E735D6020000780009F1E6@prv-mh.provo.novell.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin --- arch/x86/kernel/ldt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c index 2bcc0525f1c1..6acc9dd91f36 100644 --- a/arch/x86/kernel/ldt.c +++ b/arch/x86/kernel/ldt.c @@ -58,7 +58,7 @@ static struct ldt_struct *alloc_ldt_struct(int size) if (alloc_size > PAGE_SIZE) new_ldt->entries = vzalloc(alloc_size); else - new_ldt->entries = kzalloc(PAGE_SIZE, GFP_KERNEL); + new_ldt->entries = (void *)get_zeroed_page(GFP_KERNEL); if (!new_ldt->entries) { kfree(new_ldt); @@ -95,7 +95,7 @@ static void free_ldt_struct(struct ldt_struct *ldt) if (ldt->size * LDT_ENTRY_SIZE > PAGE_SIZE) vfree(ldt->entries); else - kfree(ldt->entries); + free_page((unsigned long)ldt->entries); kfree(ldt); } -- 2.17.1