[Mesa-dev] [PATCH v2 0/3] GEM BO padding to find OOB buffer writes

[kevin.rogovin at intel.com]

From: Kevin Rogovin <kevin.rogovin at intel.com>

This patch series adds a new debug option to pad each GEM BO
allocated by the brw_bufmgr with pseudo-(weak) random noise values
which are then checked after each batchbuffer dispatch to the kernel.
This can be quite valuable to find diffucult to track down heisenberg
style bugs.

A possible follow-up series would be to write to stderr (or
another logging mechanism) if the OOB write is to a GEM BO that
backs a GL buffer object; that features would be quite useful for
application developers.

(resending because I sent out v2 earlier today without tagging it as v2).

v2:
 Change from using rand() to using internal generating function
 (requested/suggested by Jason Ekstrand)

 Avoid having extra pointers in brw_bo struct via using the internal
 function and allocating buffer for pread at brw_bo_padding_is_good()
 (requested/suggested by Jason Ekstrand)

 Comments indicating that pread ioctl will do the required waiting
 for GPU commands to finish

Kevin Rogovin (3):
  intel/common:add debug flag for adding and checking padding on BO's
  i965: add noise padding to buffer object and function to check if
    noise is correct
  i965: if DEBUG_OUT_OF_BOUND_CHK is up, check that noise padding for
    each bo used in batchbuffer is correct

 src/intel/common/gen_debug.c                  |   1 +
 src/intel/common/gen_debug.h                  |   1 +
 src/mesa/drivers/dri/i965/brw_bufmgr.c        | 107 +++++++++++++++++++++++++-
 src/mesa/drivers/dri/i965/brw_bufmgr.h        |   8 ++
 src/mesa/drivers/dri/i965/intel_batchbuffer.c |  19 +++++
 5 files changed, 135 insertions(+), 1 deletion(-)

-- 
2.15.0