Re: [PATCH] livepatch: use FTRACE_OPS_FL_IPMODIFY

From: Petr Mladek
Date: Mon Dec 22 2014 - 12:34:23 EST


On Fri 2014-12-19 10:43:35, Petr Mladek wrote:
> On Thu 2014-12-18 09:49:35, Josh Poimboeuf wrote:
> > On Thu, Dec 18, 2014 at 08:55:21PM +0900, Masami Hiramatsu wrote:
> > > (2014/12/17 2:58), Seth Jennings wrote:
> > > > changes in v7:
> > > > - TODO: set IPMODIFY (not a blocker to moving forward)
> > >
> > > Why don't you set this?
> > > IPMODIFY series are not completely applied yet, but you can already
> > > use the flag. All you need is just set it :)
> >
> > Yeah, I don't see any reason why we can't start using this flag now.
> > How about we add this patch to the queue?
> >
> > -->8--
> >
> > Subject: livepatch: use FTRACE_OPS_FL_IPMODIFY
> >
> > Use the FTRACE_OPS_FL_IPMODIFY flag to prevent conflicts with other
> > ftrace users who also modify regs->ip.
> >
> > Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
>
> It makes sense. The flag is available even in 3.19.
>
> Reviewed-by: Petr Mladek <pmladek@xxxxxxx>

Feel free to keep the Reviewed-by if you fix the typo, see below.

> > ---
> > kernel/livepatch/core.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> > index 0004a71..bdd99975 100644
> > --- a/kernel/livepatch/core.c
> > +++ b/kernel/livepatch/core.c
> > @@ -640,7 +640,8 @@ static int klp_init_func(struct klp_object *obj, struct klp_func *func)
> >
> > ops->private = func;
> > ops->func = klp_ftrace_handler;
> > - ops->flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_DYNAMIC;
> > + ops->flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_DYNAMIC |
> > + FTRACE_FL_IPMODIFY;

Heh, there is a typo. Please replace FTRACE_FL_IPMODIFY
with FTRACE_OPS_FL_IPMODIFY ;-)

Best Regards,
Petr

> > func->fops = ops;
> > func->state = KLP_DISABLED;
> >
> > --
> > 2.1.0
> >
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