Revision 047fe6e6db9161e69271f56daaafdaf2add023b1 authored by David Weinehall on 04 August 2015, 13:55:52 UTC, committed by Daniel Vetter on 06 August 2015, 15:28:26 UTC
VBT version 196 increased the size of common_child_dev_config. The parser
code assumed that the size of this structure would not change.

The modified code now copies the amount needed based on the VBT version,
and emits a debug message if the VBT version is unknown (too new);
since the struct config block won't shrink in newer versions it should
be harmless to copy the maximum known size in such cases, so that's
what we do, but emitting the warning is probably sensible anyway.

In the longer run it might make sense to modify the parser code to
use a version/feature mapping, rather than hardcoding things like this,
but for now the variants are fairly managable.

This fixes a regression introduced in

commit 90e4f1592bb6e82f6690f0e05a8aadcf04d7bce7
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Wed Mar 25 18:45:58 2015 +0200

    drm/i915: Fix the VBT child device parsing for BSW

since we're hitting a DRM_ERROR on older platforms with this.

v2: Stricter size checks

Signed-off-by: David Weinehall <david.weinehall@linux.intel.com>
[danvet: Fixup format string.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
1 parent 5eb3e5a
Raw File
Kconfig.kasan
config HAVE_ARCH_KASAN
	bool

if HAVE_ARCH_KASAN

config KASAN
	bool "KASan: runtime memory debugger"
	depends on SLUB_DEBUG
	select CONSTRUCTORS
	help
	  Enables kernel address sanitizer - runtime memory debugger,
	  designed to find out-of-bounds accesses and use-after-free bugs.
	  This is strictly a debugging feature and it requires a gcc version
	  of 4.9.2 or later. Detection of out of bounds accesses to stack or
	  global variables requires gcc 5.0 or later.
	  This feature consumes about 1/8 of available memory and brings about
	  ~x3 performance slowdown.
	  For better error detection enable CONFIG_STACKTRACE,
	  and add slub_debug=U to boot cmdline.

choice
	prompt "Instrumentation type"
	depends on KASAN
	default KASAN_OUTLINE

config KASAN_OUTLINE
	bool "Outline instrumentation"
	help
	  Before every memory access compiler insert function call
	  __asan_load*/__asan_store*. These functions performs check
	  of shadow memory. This is slower than inline instrumentation,
	  however it doesn't bloat size of kernel's .text section so
	  much as inline does.

config KASAN_INLINE
	bool "Inline instrumentation"
	help
	  Compiler directly inserts code checking shadow memory before
	  memory accesses. This is faster than outline (in some workloads
	  it gives about x2 boost over outline instrumentation), but
	  make kernel's .text size much bigger.
	  This requires a gcc version of 5.0 or later.

endchoice

config TEST_KASAN
	tristate "Module for testing kasan for bug detection"
	depends on m && KASAN
	help
	  This is a test module doing various nasty things like
	  out of bounds accesses, use after free. It is useful for testing
	  kernel debugging features like kernel address sanitizer.

endif
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