Messages in this thread Patch in this message | | | From | Nikita Zhandarovich <> | Subject | [PATCH] drm/i915/gt: Prevent possible NULL dereference in __caps_show() | Date | Tue, 6 Feb 2024 08:45:43 -0800 |
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After falling through the switch statement to default case 'repr' is initialized with NULL, which will lead to incorrect dereference of '!repr[n]' in the following loop.
Fix it with the help of an additional check for NULL.
Found by Linux Verification Center (linuxtesting.org) with static analysis tool SVACE.
Fixes: 4ec76dbeb62b ("drm/i915/gt: Expose engine properties via sysfs") Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru> --- P.S. The NULL-deref problem might be dealt with this way but I am not certain that the rest of the __caps_show() behaviour remains correct if we end up in default case. For instance, as far as I can tell, buf might turn out to be w/o '\0'. I could use some direction if this has to be addressed as well.
drivers/gpu/drm/i915/gt/sysfs_engines.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/sysfs_engines.c b/drivers/gpu/drm/i915/gt/sysfs_engines.c index 021f51d9b456..6b130b732867 100644 --- a/drivers/gpu/drm/i915/gt/sysfs_engines.c +++ b/drivers/gpu/drm/i915/gt/sysfs_engines.c @@ -105,7 +105,7 @@ __caps_show(struct intel_engine_cs *engine, len = 0; for_each_set_bit(n, &caps, show_unknown ? BITS_PER_LONG : count) { - if (n >= count || !repr[n]) { + if (n >= count || !repr || !repr[n]) { if (GEM_WARN_ON(show_unknown)) len += sysfs_emit_at(buf, len, "[%x] ", n); } else { -- 2.25.1
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