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, 46 insertions, 0 deletions

diff --git a/tools/perf/builtin-version.c b/tools/perf/builtin-version.c
new file mode 100644
index 000000000..10f25c670
--- /dev/null
+++ b/tools/perf/builtin-version.c
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "builtin.h"
+#include "color.h"
+#include "util/debug.h"
+#include "util/header.h"
+#include <tools/config.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <subcmd/parse-options.h>
+
+struct version {
+	bool	build_options;
+};
+
+static struct version version;
+
+static struct option version_options[] = {
+	OPT_BOOLEAN(0, "build-options", &version.build_options,
+		    "display the build options"),
+	OPT_END(),
+};
+
+static const char * const version_usage[] = {
+	"perf version [<options>]",
+	NULL
+};
+
+static void library_status(void)
+{
+	for (int i = 0; supported_features[i].name; ++i)
+		feature_status__printf(&supported_features[i]);
+}
+
+int cmd_version(int argc, const char **argv)
+{
+	argc = parse_options(argc, argv, version_options, version_usage,
+			     PARSE_OPT_STOP_AT_NON_OPTION);
+
+	printf("perf version %s\n", perf_version_string);
+
+	if (version.build_options || verbose > 0)
+		library_status();
+
+	return 0;
+}