From mboxrd@z Thu Jan 1 00:00:00 1970 From: lauraa@codeaurora.org (Laura Abbott) Date: Tue, 01 Apr 2014 15:54:42 -0700 Subject: [PATCH 2/2] ARM: mm: keep rodata non-executable In-Reply-To: References: <1392339850-18686-1-git-send-email-keescook@chromium.org> <1392339850-18686-3-git-send-email-keescook@chromium.org> <20140214162257.GB2331@e103592.cambridge.arm.com> <20140217123415.GA2182@e103592.cambridge.arm.com> <532F2C48.6050509@codeaurora.org> <1395658064.3465.7.camel@linaro1.home> Message-ID: <533B43B2.1020805@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 4/1/2014 3:34 PM, Kees Cook wrote: > On Mon, Mar 24, 2014 at 3:47 AM, Jon Medhurst (Tixy) wrote: >> On Sun, 2014-03-23 at 16:21 -0600, Kees Cook wrote: >>> For this stage, how about I make this "depends on KEXEC=n && >>> KPROBES=n"? >> >> There's also ftrace (CONFIG_DYNAMIC_FTRACE I believe) which modifies >> kernel code with a call to probe_kernel_write(), which GDB uses as well. >> >> And grepping for the patch_text() function also shows >> __arch_jump_label_transform() modifies kernel code. Not sure how and >> when that gets used. > > Right, so, I'm trying to fix ftrace now, and I've hit a wall. It is as > if changes to the kernel text PMD aren't being noticed after the > kernel is running. Does anyone know why this might be happening? > > Code and details here: > https://lkml.org/lkml/2014/4/1/674 > > -Kees > We had a flush_tlb_kernel_page after the pmd_flush in our out of tree code which makes the text writeable in __patch_text. Laura -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation