Re: [PATCH 0/3] [GIT PULL][v2.6.38] tracing: fix unaligned event arrays

[Ingo Molnar <mingo@elte.hu>]

* Steven Rostedt <rostedt@goodmis.org> wrote:

> Ingo,
> 
> It was discovered that the alignment of the trace event sections
> break sparc64. The trace events are created by linker magic, so
> gcc does not realize that the structures being allocated will end
> up in an array. Without adding any alignment, x86_64 would create
> the trace event arrays with holes that would break reading the
> events in serial. The fix for that was to force a align(4) to
> keep gcc and the linker from spacing the event structures at various
> alignments. But recent changes have caused this change to break
> sparc due to bad alignment in the structures, caused by the 4 byte
> alignment.
> 
> After some discussions, Mathieu came up with the following patch set
> to correctly fix the alignment issues with the trace event structures.
> 
> Please pull the latest tip/perf/urgent tree, which can be found at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
> tip/perf/urgent
> 
> 
> Mathieu Desnoyers (3):
>       Introduce __u64_aligned and U64_ALIGN() for structure alignment in custom sections
>       tracing: Fix sparc64 alignment crash with __u64_aligned/U64_ALIGN()
>       tracepoints: Use __u64_aligned/U64_ALIGN()
> 
> ----
>  include/asm-generic/vmlinux.lds.h |   27 +++++++++++-------
>  include/linux/align-section.h     |   54 +++++++++++++++++++++++++++++++++++++
>  include/linux/compiler.h          |    8 +++--
>  include/linux/ftrace_event.h      |    2 +-
>  include/linux/syscalls.h          |   12 ++++----
>  include/linux/tracepoint.h        |   12 +++-----
>  include/trace/ftrace.h            |    8 +++---
>  include/trace/syscall.h           |    2 +-
>  kernel/trace/trace.h              |    2 +-
>  kernel/trace/trace_export.c       |    2 +-
>  10 files changed, 94 insertions(+), 35 deletions(-)

Pulled, thanks a lot Steve!

	Ingo