From: "Christian König" <christian.koenig@amd.com>
To: Tianlin Li <tli@digitalocean.com>,
kernel-hardening@lists.openwall.com, keescook@chromium.org
Cc: Alex Deucher <alexander.deucher@amd.com>,
David1.Zhou@amd.com, David Airlie <airlied@linux.ie>,
Daniel Vetter <daniel@ffwll.ch>,
amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] drm/radeon: have the callers of set_memory_*() check the return value
Date: Wed, 8 Jan 2020 13:56:47 +0100 [thread overview]
Message-ID: <b5984995-7276-97d3-a604-ddacfb89bd89@amd.com> (raw)
In-Reply-To: <20200107192555.20606-1-tli@digitalocean.com>
Am 07.01.20 um 20:25 schrieb 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_*().
I'm a little hesitate merge that. This hardware is >15 years old and
nobody of the developers have any system left to test this change on.
Would it be to much of a problem to just add something like: r =
set_memory_*(); (void)r; /* Intentionally ignored */.
Apart from that certainly a good idea to add __must_check to the functions.
Regards,
Christian.
>
> 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(-)
>
next prev parent reply other threads:[~2020-01-08 12:57 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
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 ` Christian König [this message]
2020-01-08 16:04 ` [PATCH 0/2] drm/radeon: have the callers of set_memory_*() check the return value 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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=b5984995-7276-97d3-a604-ddacfb89bd89@amd.com \
--to=christian.koenig@amd.com \
--cc=David1.Zhou@amd.com \
--cc=airlied@linux.ie \
--cc=alexander.deucher@amd.com \
--cc=amd-gfx@lists.freedesktop.org \
--cc=daniel@ffwll.ch \
--cc=dri-devel@lists.freedesktop.org \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=linux-kernel@vger.kernel.org \
--cc=tli@digitalocean.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).