FAILED: patch "[PATCH] drm/amdgpu: reject CS chunks too large for kvmalloc()" failed to apply to 6.6-stable tree

[Sasha Levin <sashal@kernel.org>]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x ba4c3c202919405f461a393e823e4b72c8518494
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107054012-failed-6.6-ba4c3c202919@kernel.org' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Thanks,
Sasha

------------------ original commit in Linus's tree ------------------

From ba4c3c202919405f461a393e823e4b72c8518494 Mon Sep 17 00:00:00 2001
From: Jesse Zhang <Jesse.Zhang@amd.com>
Date: Sun, 18 Oct 2026 19:17:57 +0800
Subject: [PATCH] drm/amdgpu: reject CS chunks too large for kvmalloc()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The CS ioctl copies every chunk with vmemdup_array_user() before it
looks at it, for whatever length_dw userspace gives. kvmalloc() warns
about allocations above INT_MAX when called without __GFP_NOWARN, so any
process with the render node can trigger a warning. On navi31, a CS with
a chunk of length_dw 0x20000000 returns -ENOMEM after:

  WARNING: mm/slub.c:6841 at __kvmalloc_node_noprof+0x5a5/0x7d0

Reject such chunks with -EINVAL before trying to copy them.

Fixes: 2098105ec65c ("drm: drop drm_[cm]alloc* helpers")
Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit dab5f5280406088591645f499f048dcfefab8d7d)
Cc: stable@vger.kernel.org
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 65e13ad445bbb..70bc53923d119 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -218,6 +218,12 @@ static int amdgpu_cs_pass1(struct amdgpu_cs_parser *p,
 
 		size = p->chunks[i].length_dw;
 
+		if (size > INT_MAX / sizeof(uint32_t)) {
+			ret = -EINVAL;
+			i--;
+			goto free_partial_kdata;
+		}
+
 		p->chunks[i].kdata = vmemdup_array_user(u64_to_user_ptr(user_chunk.chunk_data),
 							size,
 							sizeof(uint32_t));
-- 
2.53.0