[CRIU] [PATCH 1/4] pie/x86_64: syscall clobbers rcx and r11

Tycho Andersen tycho.andersen at canonical.com
Tue Jun 16 06:34:55 PDT 2015


On Tue, Jun 16, 2015 at 04:31:50PM +0300, Cyrill Gorcunov wrote:
> On Tue, Jun 16, 2015 at 07:20:56AM -0600, Tycho Andersen wrote:
> > 
> > Ok, I just added rcx because the above link said it could be clobbered
> > too, but I can send a patch to remove it if you want.
> 
> no need to, i'm fine with as is.

Ok. I think the reason we've never seen a seg fault here is that the
code path hasn't changed in a while (and neither has gcc's register
allocator apparently, yay reaload.c). When I changed it for this
patchset, gcc decided to use r11 for something (viz. the dissasembly
in the commit message), which is what caused the fault.

Tycho


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