From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:47259 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751954AbbF0A5B (ORCPT ); Fri, 26 Jun 2015 20:57:01 -0400 Subject: Patch "kprobes/x86: Return correct length in __copy_instruction()" has been added to the 4.0-stable tree To: eugene.shatokhin@rosalab.ru, gregkh@linuxfoundation.org, masami.hiramatsu.pt@hitachi.com, mingo@kernel.org Cc: , From: Date: Fri, 26 Jun 2015 17:57:01 -0700 Message-ID: <143536662158248@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled kprobes/x86: Return correct length in __copy_instruction() to the 4.0-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: kprobes-x86-return-correct-length-in-__copy_instruction.patch and it can be found in the queue-4.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From c80e5c0c23ce2282476fdc64c4b5e3d3a40723fd Mon Sep 17 00:00:00 2001 From: Eugene Shatokhin Date: Tue, 17 Mar 2015 19:09:18 +0900 Subject: kprobes/x86: Return correct length in __copy_instruction() 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 Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/kprobes/core.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -354,6 +354,7 @@ int __copy_instruction(u8 *dest, u8 *src { struct insn insn; kprobe_opcode_t buf[MAX_INSN_SIZE]; + int length; unsigned long recovered_insn = recover_probed_instruction(buf, (unsigned long)src); @@ -361,16 +362,18 @@ int __copy_instruction(u8 *dest, u8 *src return 0; kernel_insn_init(&insn, (void *)recovered_insn, MAX_INSN_SIZE); 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)) { s64 newdisp; u8 *disp; - kernel_insn_init(&insn, dest, insn.length); + kernel_insn_init(&insn, dest, length); insn_get_displacement(&insn); /* * The copied instruction uses the %rip-relative addressing @@ -394,7 +397,7 @@ 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) Patches currently in stable-queue which might be from eugene.shatokhin@rosalab.ru are queue-4.0/kprobes-x86-return-correct-length-in-__copy_instruction.patch