On Fri, Jul 28, 2017 at 12:04:47PM -0500, Josh Poimboeuf wrote: > On Fri, Jul 28, 2017 at 01:25:27PM +0200, Arnd Bergmann wrote: > > Hi Josh, > > > > I ran into two more warnings with the two patches you sent me in private, > > using gcc-7.1.1: > > > > lib/ubsan.o: warning: objtool: val_to_string.constprop.7()+0x97: leave > > instruction with modified stack frame > > .config: https://pastebin.com/dl/g04Dwdwx > > > > fs/fs_pin.o: warning: objtool: pin_kill()+0x139: stack state mismatch: > > cfa1=7+88 cfa2=7+96 > > .config: https://pastebin.com/dl/6gK6MadB > > > > I assume you are faster at analysing than me, so I have not tried to get > > to the bottom of these at all. Let me know if you need help reproducing > > the warnings. It's also possible that they are fixed by some other patches > > that you already sent but that are not in linux-next yet. > > Thanks. The first one is a relatively easy fix in objtool's drap > register handling. I have a working patch for it. > > The second one is a little trickier. > > Instead of: > > lea 0x8(%rsp), %rsp > > GCC is doing: > > lea 0x8(%rsp), %rcx > mov %rcx, %rsp > > I don't see why GCC would do that. We should probably ask some GCC > folks. Objtool isn't built to track register values, so it may be a > little tricky to deal with that pattern correctly if we can't convince > GCC to fix it. > > Anyway, I'm going to be on vacation next week, but I'll investigate > further when I get back.
I posted a patch for the first issue and I'll open a GCC bug for the second issue. -- Josh
