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Date: Tue,  7 Jan 2020 13:25:53 -0600
From: Tianlin Li <tli@...italocean.com>
To: kernel-hardening@...ts.openwall.com,
	keescook@...omium.org
Cc: Alex Deucher <alexander.deucher@....com>,
	christian.koenig@....com,
	David1.Zhou@....com,
	David Airlie <airlied@...ux.ie>,
	Daniel Vetter <daniel@...ll.ch>,
	amd-gfx@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org,
	Tianlin Li <tli@...italocean.com>
Subject: [PATCH 0/2] drm/radeon: have the callers of set_memory_*() check the return value

Right now several architectures allow their set_memory_*() family of  
functions to fail, but callers may not be checking the return values.
If set_memory_*() returns with an error, call-site assumptions may be
infact wrong to assume that it would either succeed or not succeed at  
all. Ideally, the failure of set_memory_*() should be passed up the 
call stack, and callers should examine the failure and deal with it. 

Need to fix the callers and add the __must_check attribute. They also 
may not provide any level of atomicity, in the sense that the memory 
protections may be left incomplete on failure. This issue likely has a 
few steps on effects architectures:
1)Have all callers of set_memory_*() helpers check the return value.
2)Add __must_check to all set_memory_*() helpers so that new uses do  
not ignore the return value.
3)Add atomicity to the calls so that the memory protections aren't left 
in a partial state.

This series is part of step 1. Make drm/radeon check the return value of  
set_memory_*().

Tianlin Li (2):
  drm/radeon: have the callers of set_memory_*() check the return value
  drm/radeon: change call sites to handle return value properly.

 drivers/gpu/drm/radeon/r100.c        |  3 ++-
 drivers/gpu/drm/radeon/radeon.h      |  2 +-
 drivers/gpu/drm/radeon/radeon_gart.c | 22 ++++++++++++++++++----
 drivers/gpu/drm/radeon/rs400.c       |  3 ++-
 4 files changed, 23 insertions(+), 7 deletions(-)

-- 
2.17.1

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