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, 44 insertions, 0 deletions

diff --git a/fs/overlayfs/params.h b/fs/overlayfs/params.h
new file mode 100644
index 000000000..ffd53cdd8
--- /dev/null
+++ b/fs/overlayfs/params.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+
+struct ovl_fs;
+struct ovl_config;
+
+extern const struct fs_parameter_spec ovl_parameter_spec[];
+extern const struct constant_table ovl_parameter_redirect_dir[];
+
+/* The set of options that user requested explicitly via mount options */
+struct ovl_opt_set {
+	bool metacopy;
+	bool redirect;
+	bool nfs_export;
+	bool index;
+};
+
+#define OVL_MAX_STACK 500
+
+struct ovl_fs_context_layer {
+	char *name;
+	struct path path;
+};
+
+struct ovl_fs_context {
+	struct path upper;
+	struct path work;
+	size_t capacity;
+	size_t nr; /* includes nr_data */
+	size_t nr_data;
+	struct ovl_opt_set set;
+	struct ovl_fs_context_layer *lower;
+	char *lowerdir_all; /* user provided lowerdir string */
+	bool casefold_set;
+};
+
+int ovl_init_fs_context(struct fs_context *fc);
+void ovl_free_fs(struct ovl_fs *ofs);
+int ovl_fs_params_verify(const struct ovl_fs_context *ctx,
+			 struct ovl_config *config);
+int ovl_show_options(struct seq_file *m, struct dentry *dentry);
+const char *ovl_xino_mode(struct ovl_config *config);