Re: [PATCH] livepatch: use FTRACE_OPS_FL_IPMODIFY

From: Josh Poimboeuf
Date: Mon Dec 22 2014 - 12:41:59 EST


On Mon, Dec 22, 2014 at 06:34:09PM +0100, Petr Mladek wrote:
> 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 ;-)

Argh! At least the commit message is correct ;-)

I'll send out a v2.

> Best Regards,
> Petr
>
> > > func->fops = ops;
> > > func->state = KLP_DISABLED;
> > >
> > > --
> > > 2.1.0
> > >
> > --
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--
Josh
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