FAILED: patch "[PATCH] crypto: acomp - Fix CFI failure due to type punning" failed to apply to 6.16-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.16-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-6.16.y
git checkout FETCH_HEAD
git cherry-pick -x 962ddc5a7a4b04c007bba0f3e7298cda13c62efd
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025082113-buddhism-try-6476@gregkh' --subject-prefix 'PATCH 6.16.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From 962ddc5a7a4b04c007bba0f3e7298cda13c62efd Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@kernel.org>
Date: Tue, 8 Jul 2025 17:59:54 -0700
Subject: [PATCH] crypto: acomp - Fix CFI failure due to type punning

To avoid a crash when control flow integrity is enabled, make the
workspace ("stream") free function use a consistent type, and call it
through a function pointer that has that same type.

Fixes: 42d9f6c77479 ("crypto: acomp - Move scomp stream allocation code into acomp")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/deflate.c b/crypto/deflate.c
index fe8e4ad0fee1..21404515dc77 100644
--- a/crypto/deflate.c
+++ b/crypto/deflate.c
@@ -48,9 +48,14 @@ static void *deflate_alloc_stream(void)
 	return ctx;
 }
 
+static void deflate_free_stream(void *ctx)
+{
+	kvfree(ctx);
+}
+
 static struct crypto_acomp_streams deflate_streams = {
 	.alloc_ctx = deflate_alloc_stream,
-	.cfree_ctx = kvfree,
+	.free_ctx = deflate_free_stream,
 };
 
 static int deflate_compress_one(struct acomp_req *req,
diff --git a/crypto/zstd.c b/crypto/zstd.c
index ebeadc1f3b5f..c2a19cb0879d 100644
--- a/crypto/zstd.c
+++ b/crypto/zstd.c
@@ -54,9 +54,14 @@ static void *zstd_alloc_stream(void)
 	return ctx;
 }
 
+static void zstd_free_stream(void *ctx)
+{
+	kvfree(ctx);
+}
+
 static struct crypto_acomp_streams zstd_streams = {
 	.alloc_ctx = zstd_alloc_stream,
-	.cfree_ctx = kvfree,
+	.free_ctx = zstd_free_stream,
 };
 
 static int zstd_init(struct crypto_acomp *acomp_tfm)
diff --git a/include/crypto/internal/acompress.h b/include/crypto/internal/acompress.h
index ffffd88bbbad..2d97440028ff 100644
--- a/include/crypto/internal/acompress.h
+++ b/include/crypto/internal/acompress.h
@@ -63,10 +63,7 @@ struct crypto_acomp_stream {
 struct crypto_acomp_streams {
 	/* These must come first because of struct scomp_alg. */
 	void *(*alloc_ctx)(void);
-	union {
-		void (*free_ctx)(void *);
-		void (*cfree_ctx)(const void *);
-	};
+	void (*free_ctx)(void *);
 
 	struct crypto_acomp_stream __percpu *streams;
 	struct work_struct stream_work;