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* [PATCH 0/2] drm/radeon: have the callers of set_memory_*() check the return value
@ 2020-01-07 19:25 Tianlin Li
  2020-01-07 19:25 ` [PATCH 1/2] " Tianlin Li
                   ` (2 more replies)
  0 siblings, 3 replies; 10+ messages in thread
From: Tianlin Li @ 2020-01-07 19:25 UTC (permalink / raw)
  To: kernel-hardening, keescook
  Cc: Alex Deucher, christian.koenig, David1.Zhou, David Airlie,
	Daniel Vetter, amd-gfx, dri-devel, linux-kernel, Tianlin Li

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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Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-01-07 19:25 [PATCH 0/2] drm/radeon: have the callers of set_memory_*() check the return value Tianlin Li
2020-01-07 19:25 ` [PATCH 1/2] " Tianlin Li
2020-01-07 19:25 ` [PATCH 2/2] drm/radeon: change call sites to handle return value properly Tianlin Li
2020-01-08 12:56 ` [PATCH 0/2] drm/radeon: have the callers of set_memory_*() check the return value Christian König
2020-01-08 16:04   ` Tianlin Li
2020-01-08 17:39   ` Kees Cook
2020-01-08 17:51     ` Alex Deucher
2020-01-09 10:15       ` Christian König
2020-01-09 10:49         ` Thomas Zimmermann
2020-01-09 20:16           ` Alex Deucher

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