Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

From: Al Viro
Date: Fri May 29 2020 - 16:09:38 EST

On Fri, May 29, 2020 at 12:31:04PM -0700, Linus Torvalds wrote:
> On Fri, May 29, 2020 at 9:50 AM Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
> >
> > From staring at the asm I think the generated code is correct, it's just
> > that the nested likelys with ftrace profiling cause GCC to converge the
> > error/success paths. But objtool doesn't do register value tracking so
> > it's not smart enough to know that it's safe.
> I'm surprised that gcc doesn't end up doing the obvious CSE and then
> branch following and folding it all away in the end, but your patch is
> obviously the right thing to do regardless, so ack on that.
> Al - I think this had best go into your uaccess cleanup branch with
> that csum-wrapper update, to avoid any unnecessary conflicts or
> dependencies.

Sure, just let me verify that other branches don't introduce anything
of that sort...