From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from wa-out-1112.google.com (wa-out-1112.google.com [209.85.146.178]) by ozlabs.org (Postfix) with ESMTP id E05A3DDDF5 for ; Tue, 26 Jun 2007 16:19:34 +1000 (EST) Received: by wa-out-1112.google.com with SMTP id m28so2237151wag for ; Mon, 25 Jun 2007 23:19:33 -0700 (PDT) Message-ID: <863e9df20706252319j239eaf44wee7a46ad742c9585@mail.gmail.com> Date: Tue, 26 Jun 2007 11:49:33 +0530 From: "Abhishek Sagar" To: "Michael Ellerman" Subject: Re: [PATCH 3/3] Make jprobes a little safer for users In-Reply-To: <7a070581b2fe53ea65216e86c86abc4f40464341.1182822366.git.michael@ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed References: <78935473b1f70c863ab0be7d6cf4bcb04922b20b.1182822366.git.michael@ellerman.id.au> <7a070581b2fe53ea65216e86c86abc4f40464341.1182822366.git.michael@ellerman.id.au> Cc: linux-arch@vger.kernel.org, Andrew Morton , linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, anil.s.keshavamurthy@intel.com, linuxppc-dev@ozlabs.org, Christoph Hellwig List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 6/26/07, Michael Ellerman wrote: > We can then use that in register_jprobe() to check that the entry point > we're passed is actually in the kernel text, rather than just some random > value. A similar cleanup is possible even for return probes then. I wonder if there are any kprobe related scenarios where the executable code may be located outside the core kernel text region (e.g, ITCM?). In that case would it also be wrong to assume that the jprobe handler may be situated outside the kernel core text / module region? Would it then make sense to move this check from register_jprobe() to the arch dependent code? > int __kprobes register_jprobe(struct jprobe *jp) > { > + unsigned long addr = arch_deref_entry_point(jp->entry); > + > + if (!kernel_text_address(addr)) > + return -EINVAL; Seems like you're checking for the jprobe handler to be within kernel/module range. Why not narrow this down to just module range (!module_text_address(addr), say)? Core kernel functions would not be ending with a 'jprobe_return()' anyway. -- Abhishek Sagar - > 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/