From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752652AbdCNNeC (ORCPT ); Tue, 14 Mar 2017 09:34:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:40199 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751563AbdCNNP7 (ORCPT ); Tue, 14 Mar 2017 09:15:59 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Paul Burton , Leonid Yegoshin , linux-mips@linux-mips.org, Ralf Baechle , Jiri Slaby Subject: [PATCH 3.12 09/60] MIPS: Fix get_frame_info() handling of microMIPS function size Date: Tue, 14 Mar 2017 14:15:00 +0100 Message-Id: X-Mailer: git-send-email 2.12.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Paul Burton 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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: Jiri Slaby --- 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 5b91c4d88f46..664e61ef690b 100644 --- a/arch/mips/kernel/process.c +++ b/arch/mips/kernel/process.c @@ -315,9 +315,9 @@ 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; @@ -326,11 +326,9 @@ 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]; -- 2.12.0