----- On Feb 18, 2019, at 7:26 AM, Greg Kroah-Hartman 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... It seems to still be in the arm patch tracking system: https://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=8834/1 If I understand its status correctly, it is applied to the arm tree, but perhaps it has not been pulled by Linus yet ? The code is still broken in Linus' master. It would be important to get this arm kprobes fix upstream before 5.0 final. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
