lkml.org 
[lkml]   [2019]   [May]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Oops caused by race between livepatch and ftrace
On Tue, 21 May 2019 09:16:29 -0500
Josh Poimboeuf <jpoimboe@redhat.com> wrote:

> > Hmm, this may blow up with lockdep, as I believe we already have a
> > locking dependency of:
> >
> > text_mutex -> ftrace_lock
> >
> > And this will reverses it. (kprobes appears to take the locks in this
> > order).
> >
> > Perhaps have live kernel patching grab ftrace_lock?
>
> Where does kprobes call into ftrace with the text_mutex? I couldn't
> find it.

Hmm, maybe it doesn't. I was looking at the arm_kprobe_ftrace() but
it doesn't call it with text_mutex().

Maybe it is fine, but we had better perform a lot of testing with
lockdep on to make sure.

-- Steve

\
 
 \ /
  Last update: 2019-05-21 16:43    [W:0.117 / U:2.748 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site