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...