From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754122AbcARDhm (ORCPT ); Sun, 17 Jan 2016 22:37:42 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:59266 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752596AbcARDWD (ORCPT ); Sun, 17 Jan 2016 22:22:03 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Martin Schwidefsky" , "Michael Holzheu" Date: Mon, 18 Jan 2016 03:18:35 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 19/70] s390/dis: Fix handling of format specifiers In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.247 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.76-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Michael Holzheu commit 272fa59ccb4fc802af28b1d699c2463db6a71bf7 upstream. The print_insn() function returns strings like "lghi %r1,0". To escape the '%' character in sprintf() a second '%' is used. For example "lghi %%r1,0" is converted into "lghi %r1,0". After print_insn() the output string is passed to printk(). Because format specifiers like "%r" or "%f" are ignored by printk() this works by chance most of the time. But for instructions with control registers like "lctl %c6,%c6,780" this fails because printk() interprets "%c" as character format specifier. Fix this problem and escape the '%' characters twice. For example "lctl %%%%c6,%%%%c6,780" is then converted by sprintf() into "lctl %%c6,%%c6,780" and by printk() into "lctl %c6,%c6,780". Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky [bwh: Backported to 3.2: drop the OPERAND_VR case] Signed-off-by: Ben Hutchings --- arch/s390/kernel/dis.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) --- a/arch/s390/kernel/dis.c +++ b/arch/s390/kernel/dis.c @@ -1503,14 +1503,21 @@ static int print_insn(char *buffer, unsi } if (separator) ptr += sprintf(ptr, "%c", separator); + /* + * Use four '%' characters below because of the + * following two conversions: + * + * 1) sprintf: %%%%r -> %%r + * 2) printk : %%r -> %r + */ if (operand->flags & OPERAND_GPR) - ptr += sprintf(ptr, "%%r%i", value); + ptr += sprintf(ptr, "%%%%r%i", value); else if (operand->flags & OPERAND_FPR) - ptr += sprintf(ptr, "%%f%i", value); + ptr += sprintf(ptr, "%%%%f%i", value); else if (operand->flags & OPERAND_AR) - ptr += sprintf(ptr, "%%a%i", value); + ptr += sprintf(ptr, "%%%%a%i", value); else if (operand->flags & OPERAND_CR) - ptr += sprintf(ptr, "%%c%i", value); + ptr += sprintf(ptr, "%%%%c%i", value); else if (operand->flags & OPERAND_PCREL) ptr += sprintf(ptr, "%lx", (signed int) value + addr);