Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1344410

Re: linux-next: build failure after merge of the akpm-current tree

Show all headers | View raw

On 02/25/2016 09:44 PM, Stephen Rothwell wrote:
> The addition of the "u64 _pkey" has presumably changed the alignment of
> the enclosing union on (some) 32 bit platforms and so added padding
> after the si_code field.  This is a user API issue. :-(
> 
> [As an aside, I am pretty sure that we should not be using "u64" in a
> uapi header in any case.]

Ahh, so if _addr_bnd wasn't 64-bit-aligned, the compiler is free to
align it and enlarge the structure.  But, this only applied to
architectures where _addr_bnd wasn't 64-bit-aligned:

Would anybody object to _pkey being an 'unsigned long'?  It would at
least keep existing 64-bit userspace (mostly my tests) from having to
change.

Here's the snippet of the struct in question:

>                         union {
>                                 /* used when si_code=SEGV_BNDERR */
>                                 struct {
>                                         void __user *_lower;
>                                         void __user *_upper;
>                                 } _addr_bnd;
>                                 /* used when si_code=SEGV_PKUERR */
>                                 u64 _pkey;
>                         };

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

linux-next: build failure after merge of the akpm-current tree Stephen Rothwell <sfr@canb.auug.org.au> - 2016-02-26 06:50 +0100
  Re: linux-next: build failure after merge of the akpm-current tree Dave Hansen <dave.hansen@linux.intel.com> - 2016-02-26 17:20 +0100
  Re: linux-next: build failure after merge of the akpm-current tree Dave Hansen <dave.hansen@linux.intel.com> - 2016-02-26 21:20 +0100
    Re: linux-next: build failure after merge of the akpm-current tree Andrew Morton <akpm@linux-foundation.org> - 2016-02-26 22:40 +0100
      Re: linux-next: build failure after merge of the akpm-current tree Stephen Rothwell <sfr@canb.auug.org.au> - 2016-02-26 23:50 +0100

csiph-web