From 237fe68a9a82bfbe5584d6cae1a5bcc7142fc046 Mon Sep 17 00:00:00 2001
From: Jason Ekstrand <jason@jlekstrand.net>
Date: Thu, 8 Jul 2021 10:48:17 -0500
Subject: drm/i915/gem: Disallow creating contexts with too many engines
Git-commit: ebb1ca741bee54e833ecabbd95090c92210c65d2
Patch-mainline: v5.15-rc1
References: jsc#SLE-22601
There's no sense in allowing userspace to create more engines than it
can possibly access via execbuf.
Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-13-jason@jlekstrand.net
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/gem/i915_gem_context.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 5eca91ded342..0ba8506fb966 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -1639,11 +1639,11 @@ set_engines(struct i915_gem_context *ctx,
return -EINVAL;
}
- /*
- * Note that I915_EXEC_RING_MASK limits execbuf to only using the
- * first 64 engines defined here.
- */
num_engines = (args->size - sizeof(*user)) / sizeof(*user->engines);
+ /* RING_MASK has no shift so we can use it directly here */
+ if (num_engines > I915_EXEC_RING_MASK + 1)
+ return -EINVAL;
+
set.engines = alloc_engines(num_engines);
if (!set.engines)
return -ENOMEM;
--
2.33.1