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From:   coverity-bot <keescook@chromium.org>
Date:   Fri, 4 Nov 2022 12:41:01 -0700
To:     Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Cc:     Alex Deucher <alexander.deucher@amd.com>,
        Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>,
        David Airlie <airlied@gmail.com>,
        amd-gfx@lists.freedesktop.org, Oded Gabbay <oded.gabbay@gmail.com>,
        Jay Cornwall <Jay.Cornwall@amd.com>, Ben Goz <ben.goz@amd.com>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        Kent Russell <kent.russell@amd.com>,
        Felix Kuehling <Felix.Kuehling@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>,
        Daniel Vetter <daniel@ffwll.ch>, Amber Lin <Amber.Lin@amd.com>,
        "Gustavo A. R. Silva" <gustavo@embeddedor.com>,
        linux-next@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Coverity: kfd_parse_subtype_cache(): Memory - corruptions
Message-ID: <202211041239.2B98F280@keescook>
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Hello!

This is an experimental semi-automated report about issues detected by
Coverity from a scan of next-20221104 as part of the linux-next scan project:
https://scan.coverity.com/projects/linux-next-weekly-scan

You're getting this email because you were associated with the identified
lines of code (noted below) that were touched by commits:

  Fri Dec 8 23:08:59 2017 -0500
    3a87177eb141 ("drm/amdkfd: Add topology support for dGPUs")

Coverity reported the following:

*** CID 1527133:  Memory - corruptions  (OVERRUN)
drivers/gpu/drm/amd/amdkfd/kfd_crat.c:1113 in kfd_parse_subtype_cache()
1107     			props->cache_size = cache->cache_size;
1108     			props->cacheline_size = cache->cache_line_size;
1109     			props->cachelines_per_tag = cache->lines_per_tag;
1110     			props->cache_assoc = cache->associativity;
1111     			props->cache_latency = cache->cache_latency;
1112
vvv     CID 1527133:  Memory - corruptions  (OVERRUN)
vvv     Overrunning array "cache->sibling_map" of 32 bytes by passing it to a function which accesses it at byte offset 63 using argument "64UL". [Note: The source code implementation of the function has been overridden by a builtin model.]
1113     			memcpy(props->sibling_map, cache->sibling_map,
1114     					sizeof(props->sibling_map));
1115
1116     			/* set the sibling_map_size as 32 for CRAT from ACPI */
1117     			props->sibling_map_size = CRAT_SIBLINGMAP_SIZE;
1118

If this is a false positive, please let us know so we can mark it as
such, or teach the Coverity rules to be smarter. If not, please make
sure fixes get into linux-next. :) For patches fixing this, please
include these lines (but double-check the "Fixes" first):

Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1527133 ("Memory - corruptions")
Fixes: 3a87177eb141 ("drm/amdkfd: Add topology support for dGPUs")

I'm not sure why this suddenly appeared after 5 years, but the read
over-run looks legit:

struct crat_subtype_cache {
        ...
        uint8_t         sibling_map[CRAT_SIBLINGMAP_SIZE];

#define CRAT_SIBLINGMAP_SIZE    32


struct kfd_cache_properties {
        ...
        uint8_t                 sibling_map[CACHE_SIBLINGMAP_SIZE];

#define CACHE_SIBLINGMAP_SIZE 64

Thanks for your attention!

-- 
Coverity-bot