dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel()grafted

When dma_device_put() drops the last reference on chan->device->ref,
dma_device_release() runs and may free the dma_device along with its
channels.

dma_chan_put() then still reads chan->device->owner via
dma_chan_to_owner() for the trailing module_put(). KASAN catches it:

	slab-use-after-free in dma_chan_put+0x3e6/0x4c0
	Read of size 8 by task insmod/6319
	Freed by task 6319:
	  kfree+0x225/0x470
	  dma_chan_put+0x395/0x4c0
	  dmaengine_put+0xf8/0x160

Cache the module owner in dma_chan_put() before the put so the trailing
module_put() does not need chan->device.

Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct")
Suggested-by: Sashiko <sashiko-bot@kernel.org>
Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Shivank Garg <shivankg@amd.com>
Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 24 insertions, 0 deletions

diff --git a/include/crypto/blowfish.h b/include/crypto/blowfish.h
new file mode 100644
index 000000000..9b384670b
--- /dev/null
+++ b/include/crypto/blowfish.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Common values for blowfish algorithms
+ */
+
+#ifndef _CRYPTO_BLOWFISH_H
+#define _CRYPTO_BLOWFISH_H
+
+#include <linux/types.h>
+#include <linux/crypto.h>
+
+#define BF_BLOCK_SIZE 8
+#define BF_MIN_KEY_SIZE 4
+#define BF_MAX_KEY_SIZE 56
+
+struct bf_ctx {
+	u32 p[18];
+	u32 s[1024];
+};
+
+int blowfish_setkey(struct crypto_tfm *tfm, const u8 *key,
+		    unsigned int key_len);
+
+#endif