Messages in this thread | | | Date | Tue, 01 Apr 2014 15:54:42 -0700 | From | Laura Abbott <> | Subject | Re: [PATCH 2/2] ARM: mm: keep rodata non-executable |
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On 4/1/2014 3:34 PM, Kees Cook wrote: > On Mon, Mar 24, 2014 at 3:47 AM, Jon Medhurst (Tixy) <tixy@linaro.org> 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
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