On Mon, 18 Feb 2019 13:26:31 +0100 Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > On Wed, Feb 06, 2019 at 01:41:15PM +0900, Masami Hiramatsu wrote: > > On Tue, 5 Feb 2019 15:06:10 +0000 > > Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > > > > 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. :( > > > > Ah, I thought it had been fixed as same as x86. > > On x86, all optprobe_template_* are defined as kprobe_opcode_t [], > > but on arm, it still be kprobe_opcode_t. > > > > Hmm, but I think we should use kprobe_opcode_t [] or char[] as asm/sections.h does. > > OK, I'll prepare for the change. > > Did this ever get fixed in Linus's tree? If so, what is the git commit > id, I can't seem to find anything... I would like to wait for picking up Mathieu's patch which I acked, since it is simpler and minimum fix. https://patchwork.kernel.org/patch/10797511/ After this, I will send my update to change the optprobe_template_* definitions which will involves wider code, and need to be tested. Thank you, -- Masami Hiramatsu <mhiramat@xxxxxxxxxx>
