Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753408AbdFGXeT (ORCPT ); Wed, 7 Jun 2017 19:34:19 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:50704 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753245AbdFGXFN (ORCPT ); Wed, 7 Jun 2017 19:05:13 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Paul Burton , Leonid Yegoshin , linux-mips@linux-mips.org, Ralf Baechle , Willy Tarreau Subject: [PATCH 3.10 144/250] MIPS: Fix get_frame_info() handling of microMIPS function size Date: Thu, 8 Jun 2017 00:58:50 +0200 Message-Id: <1496876436-32402-145-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1496876436-32402-1-git-send-email-w@1wt.eu> References: <1496876436-32402-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2294 Lines: 59 From: Paul Burton commit b6c7a324df37bf05ef7a2c1580683cf10d082d97 upstream. get_frame_info() is meant to iterate over up to the first 128 instructions within a function, but for microMIPS kernels it will not reach that many instructions unless the function is 512 bytes long since we calculate the maximum number of instructions to check by dividing the function length by the 4 byte size of a union mips_instruction. In microMIPS kernels this won't do since instructions are variable length. Fix this by instead checking whether the pointer to the current instruction has reached the end of the function, and use max_insns as a simple constant to check the number of iterations against. Signed-off-by: Paul Burton Fixes: 34c2f668d0f6 ("MIPS: microMIPS: Add unaligned access support.") Cc: Leonid Yegoshin Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14530/ Signed-off-by: Ralf Baechle Signed-off-by: Willy Tarreau --- arch/mips/kernel/process.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c index 71110b9..e67e17a 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -312,9 +312,9 @@ static inline int is_sp_move_ins(union mips_instruction *ip) static int get_frame_info(struct mips_frame_info *info) { bool is_mmips = IS_ENABLED(CONFIG_CPU_MICROMIPS); - union mips_instruction insn, *ip; - unsigned max_insns = info->func_size / sizeof(union mips_instruction); - unsigned i; + union mips_instruction insn, *ip, *ip_end; + const unsigned int max_insns = 128; + unsigned int i; info->pc_offset = -1; info->frame_size = 0; @@ -323,11 +323,9 @@ static int get_frame_info(struct mips_frame_info *info) if (!ip) goto err; - if (max_insns == 0) - max_insns = 128U; /* unknown function size */ - max_insns = min(128U, max_insns); + ip_end = (void *)ip + info->func_size; - for (i = 0; i < max_insns; i++, ip++) { + for (i = 0; i < max_insns && ip < ip_end; i++, ip++) { if (is_mmips && mm_insn_16bit(ip->halfword[0])) { insn.halfword[0] = 0; insn.halfword[1] = ip->halfword[0]; -- 2.8.0.rc2.1.gbe9624a