Messages in this thread | | | Date | Thu, 27 Jun 2019 20:17:25 -0500 | From | Josh Poimboeuf <> | Subject | Re: [PATCH] ftrace: Remove possible deadlock between register_kprobe() and ftrace_run_update_code() |
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On Thu, Jun 27, 2019 at 09:13:04PM -0400, Steven Rostedt wrote: > On Thu, 27 Jun 2019 18:19:52 -0500 > Josh Poimboeuf <jpoimboe@redhat.com> wrote: > > > > Maybe a comment or two would help though. > > > > I'm adding the following change. Care to add a "reviewed-by" for this > one? > > -- Steve > > diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c > index 33786044d5ac..d7e93b2783fd 100644 > --- a/arch/x86/kernel/ftrace.c > +++ b/arch/x86/kernel/ftrace.c > @@ -36,6 +36,11 @@ > > int ftrace_arch_code_modify_prepare(void) > { > + /* > + * Need to grab text_mutex to prevent a race from module loading > + * and live kernel patching from changing the text permissions while > + * ftrace has it set to "read/write". > + */ > mutex_lock(&text_mutex); > set_kernel_text_rw(); > set_all_modules_text_rw();
For the patch+comment:
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
-- Josh
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