On Mon, Feb 4, 2019 at 7:15 PM Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> wrote: > > Hi, > > I notice this commit as a possible culprit of the illegal instructions my lttng > users are noticing on arm32 when using kprobes on a v4.19.13 Linux kernel > in a Yocto environment [1]. They were able to reproduce the issue with perf > as well. > > commit e46daee53bb50bde38805f1823a182979724c229 > Author: Kees Cook <keescook@xxxxxxxxxxxx> > Date: Tue Oct 30 22:12:56 2018 +0100 > > ARM: 8806/1: kprobes: Fix false positive with FORTIFY_SOURCE > > I *think* the intent there was to do > > - memcpy(code, &optprobe_template_entry, > + memcpy(code, (unsigned long *)&optprobe_template_entry, > > But if you look at the commit, the "&" seems to have been stripped away, > which happens to change the behavior significantly. Yeah, this was a typo on my part. :( > Has this change ever been runtime-tested ? I thought I had, given the details from the original bug report, but clearly it didn't exercise it. Thanks for fixing this! -Kees > > It has been backported to: > - 4.19 stable as commit 3fe0c68aea21 > - 4.14 stable as commit f9e0bc710347 > > Thanks, > > Mathieu > > [1] https://bugs.lttng.org/issues/1174 > > -- > Mathieu Desnoyers > EfficiOS Inc. > http://www.efficios.com -- Kees Cook
