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Message-Id: <20200107192555.20606-1-tli@digitalocean.com>
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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