On 01/25/2018, 04:12 PM, Greg Kroah-Hartman wrote:
On Thu, Jan 25, 2018 at 03:47:32PM +0100, Jiri Slaby wrote:
On 01/25/2018, 03:30 PM, Thomas Gleixner wrote:
So what's the problem?
The problem I see is that every stable kernel now requires updated strace with their commit from yesterday to build correctly. In particular, the new stable kernels cause rpm build failures of strace in all our distros (based on those stable kernels). Sure, we can patch strace in every distro every nth kernel update, but it's mere impractical. Kernel should not break userspace, right?
Well, when userspace is doing something stupid... :)
No doubt... But does that mean we no longer maintain the "no userspace breakage even if it is stupid" rule?
BTW why was the patch applied to stable? We actually do pass -fno-strict-overflow.
The same reason it was applied upstream, it fixes a reported issue.
Does that mean that all UBSAN overflow error reports are not valid because of how we build the kernel?
IMO yes, because with the option, signed overflow is not undefined.
In the long term, it would be nice to get rid of *all* signed integer overflows and kill the compiler option from Makefile. Therefore the fixes are indeed very valid in upstream.
thanks,