Re: [PATCH 0/7] libsanitizer: merge from trunk

[Jakub Jelinek <jakub@redhat.com>]

On Fri, Oct 26, 2018 at 09:48:54AM -0500, Bill Seurer wrote:
> On 10/26/18 03:57, Jakub Jelinek wrote:
> > On Thu, Oct 25, 2018 at 12:49:42PM +0200, Jakub Jelinek wrote:
> > > On Thu, Oct 25, 2018 at 12:15:46PM +0200, marxin wrote:
> > > > I've just finished my first merge from libsanitizer mainline. Overall it
> > > > looks fine, apparently ABI hasn't changed and so that SONAME bump is not
> > > > needed.
> > > 
> > > Given the 6/7 patch, I think you need to bump libasan soname (it would be
> > > weird to bump it on powerpc64* only).
> > 
> > BTW, how can shadow offset be 1UL<<44 on powerpc64?  That seems like they
> > don't want to support anything but very recent kernels.
> > E.g. looking at Linux 3.4 arch/powerpc/include/asm/processor.h
> > I see
> > /* 64-bit user address space is 44-bits (16TB user VM) */
> > #define TASK_SIZE_USER64 (0x0000100000000000UL)
> > so, the new choice must be incompatible with lots of kernels out there.
> > Move recent kernels have:
> > #define TASK_SIZE_64TB  (0x0000400000000000UL)
> > #define TASK_SIZE_128TB (0x0000800000000000UL)
> > #define TASK_SIZE_512TB (0x0002000000000000UL)
> > #define TASK_SIZE_1PB   (0x0004000000000000UL)
> > #define TASK_SIZE_2PB   (0x0008000000000000UL)
> > #define TASK_SIZE_4PB   (0x0010000000000000UL)
> > but 4.15 still tops at 512TB, 4.10 has just 64TB as the only choice, 3.8 as
> > well.
> > 
> > CCing Bill as he made this change.
> > 
> > 	Jakub
> > 
> 
> At the time for llvm the concern was to get it to work on newer kernels and
> not worry (much) about the older ones.  I did spend some time trying to get
> it to work for both.

Which exact task size doesn't work if shadow offset is 2TB and why?

	Jakub