Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933445AbbFEOrX (ORCPT ); Fri, 5 Jun 2015 10:47:23 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:59455 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754528AbbFEN6q (ORCPT ); Fri, 5 Jun 2015 09:58:46 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Eugene Shatokhin , Masami Hiramatsu , Ingo Molnar , Luis Henriques Subject: [PATCH 3.16.y-ckt 001/110] kprobes/x86: Return correct length in __copy_instruction() Date: Fri, 5 Jun 2015 14:56:44 +0100 Message-Id: <1433512713-22984-2-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1433512713-22984-1-git-send-email-luis.henriques@canonical.com> References: <1433512713-22984-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2268 Lines: 64 3.16.7-ckt13 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Eugene Shatokhin commit c80e5c0c23ce2282476fdc64c4b5e3d3a40723fd upstream. On x86-64, __copy_instruction() always returns 0 (error) if the instruction uses %rip-relative addressing. This is because kernel_insn_init() is called the second time for 'insn' instance in such cases and sets all its fields to 0. Because of this, trying to place a kprobe on such instruction will fail, register_kprobe() will return -EINVAL. This patch fixes the problem. Signed-off-by: Eugene Shatokhin Signed-off-by: Masami Hiramatsu Link: http://lkml.kernel.org/r/20150317100918.28349.94654.stgit@localhost.localdomain Signed-off-by: Ingo Molnar [ luis: backported to 3.16: used Eugene's backport for 3.16.y-3.18.y ] Signed-off-by: Luis Henriques --- arch/x86/kernel/kprobes/core.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 93d2c04c6f8f..f2e281cf8c19 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -330,13 +330,16 @@ int __copy_instruction(u8 *dest, u8 *src) { struct insn insn; kprobe_opcode_t buf[MAX_INSN_SIZE]; + int length; kernel_insn_init(&insn, (void *)recover_probed_instruction(buf, (unsigned long)src)); insn_get_length(&insn); + length = insn.length; + /* Another subsystem puts a breakpoint, failed to recover */ if (insn.opcode.bytes[0] == BREAKPOINT_INSTRUCTION) return 0; - memcpy(dest, insn.kaddr, insn.length); + memcpy(dest, insn.kaddr, length); #ifdef CONFIG_X86_64 if (insn_rip_relative(&insn)) { @@ -366,7 +369,7 @@ int __copy_instruction(u8 *dest, u8 *src) *(s32 *) disp = (s32) newdisp; } #endif - return insn.length; + return length; } static int arch_copy_kprobe(struct kprobe *p) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/