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, 140 insertions, 0 deletions

diff --git a/scripts/gcc-plugins/gcc-generate-simple_ipa-pass.h b/scripts/gcc-plugins/gcc-generate-simple_ipa-pass.h
new file mode 100644
index 000000000..33093ccc9
--- /dev/null
+++ b/scripts/gcc-plugins/gcc-generate-simple_ipa-pass.h
@@ -0,0 +1,140 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Generator for SIMPLE_IPA pass related boilerplate code/data
+ *
+ * Supports gcc 4.5-6
+ *
+ * Usage:
+ *
+ * 1. before inclusion define PASS_NAME
+ * 2. before inclusion define NO_* for unimplemented callbacks
+ *    NO_GATE
+ *    NO_EXECUTE
+ * 3. before inclusion define PROPERTIES_* and TODO_FLAGS_* to override
+ *    the default 0 values
+ * 4. for convenience, all the above will be undefined after inclusion!
+ * 5. the only exported name is make_PASS_NAME_pass() to register with gcc
+ */
+
+#ifndef PASS_NAME
+#error at least PASS_NAME must be defined
+#else
+#define __GCC_PLUGIN_STRINGIFY(n)	#n
+#define _GCC_PLUGIN_STRINGIFY(n)	__GCC_PLUGIN_STRINGIFY(n)
+#define _GCC_PLUGIN_CONCAT2(x, y)	x ## y
+#define _GCC_PLUGIN_CONCAT3(x, y, z)	x ## y ## z
+
+#define __PASS_NAME_PASS_DATA(n)	_GCC_PLUGIN_CONCAT2(n, _pass_data)
+#define _PASS_NAME_PASS_DATA		__PASS_NAME_PASS_DATA(PASS_NAME)
+
+#define __PASS_NAME_PASS(n)		_GCC_PLUGIN_CONCAT2(n, _pass)
+#define _PASS_NAME_PASS			__PASS_NAME_PASS(PASS_NAME)
+
+#define _PASS_NAME_NAME			_GCC_PLUGIN_STRINGIFY(PASS_NAME)
+
+#define __MAKE_PASS_NAME_PASS(n)	_GCC_PLUGIN_CONCAT3(make_, n, _pass)
+#define _MAKE_PASS_NAME_PASS		__MAKE_PASS_NAME_PASS(PASS_NAME)
+
+#ifdef NO_GATE
+#define _GATE NULL
+#define _HAS_GATE false
+#else
+#define __GATE(n)			_GCC_PLUGIN_CONCAT2(n, _gate)
+#define _GATE				__GATE(PASS_NAME)
+#define _HAS_GATE true
+#endif
+
+#ifdef NO_EXECUTE
+#define _EXECUTE NULL
+#define _HAS_EXECUTE false
+#else
+#define __EXECUTE(n)			_GCC_PLUGIN_CONCAT2(n, _execute)
+#define _EXECUTE			__EXECUTE(PASS_NAME)
+#define _HAS_EXECUTE true
+#endif
+
+#ifndef PROPERTIES_REQUIRED
+#define PROPERTIES_REQUIRED 0
+#endif
+
+#ifndef PROPERTIES_PROVIDED
+#define PROPERTIES_PROVIDED 0
+#endif
+
+#ifndef PROPERTIES_DESTROYED
+#define PROPERTIES_DESTROYED 0
+#endif
+
+#ifndef TODO_FLAGS_START
+#define TODO_FLAGS_START 0
+#endif
+
+#ifndef TODO_FLAGS_FINISH
+#define TODO_FLAGS_FINISH 0
+#endif
+
+namespace {
+static const pass_data _PASS_NAME_PASS_DATA = {
+		.type			= SIMPLE_IPA_PASS,
+		.name			= _PASS_NAME_NAME,
+		.optinfo_flags		= OPTGROUP_NONE,
+		.tv_id			= TV_NONE,
+		.properties_required	= PROPERTIES_REQUIRED,
+		.properties_provided	= PROPERTIES_PROVIDED,
+		.properties_destroyed	= PROPERTIES_DESTROYED,
+		.todo_flags_start	= TODO_FLAGS_START,
+		.todo_flags_finish	= TODO_FLAGS_FINISH,
+};
+
+class _PASS_NAME_PASS : public simple_ipa_opt_pass {
+public:
+	_PASS_NAME_PASS() : simple_ipa_opt_pass(_PASS_NAME_PASS_DATA, g) {}
+
+#ifndef NO_GATE
+	virtual bool gate(function *) { return _GATE(); }
+#endif
+
+	virtual opt_pass *clone() { return new _PASS_NAME_PASS(); }
+
+#ifndef NO_EXECUTE
+	virtual unsigned int execute(function *) { return _EXECUTE(); }
+#endif
+};
+}
+
+opt_pass *_MAKE_PASS_NAME_PASS(void)
+{
+	return new _PASS_NAME_PASS();
+}
+
+/* clean up user provided defines */
+#undef PASS_NAME
+#undef NO_GATE
+#undef NO_EXECUTE
+
+#undef PROPERTIES_DESTROYED
+#undef PROPERTIES_PROVIDED
+#undef PROPERTIES_REQUIRED
+#undef TODO_FLAGS_FINISH
+#undef TODO_FLAGS_START
+
+/* clean up generated defines */
+#undef _EXECUTE
+#undef __EXECUTE
+#undef _GATE
+#undef __GATE
+#undef _GCC_PLUGIN_CONCAT2
+#undef _GCC_PLUGIN_CONCAT3
+#undef _GCC_PLUGIN_STRINGIFY
+#undef __GCC_PLUGIN_STRINGIFY
+#undef _HAS_EXECUTE
+#undef _HAS_GATE
+#undef _MAKE_PASS_NAME_PASS
+#undef __MAKE_PASS_NAME_PASS
+#undef _PASS_NAME_NAME
+#undef _PASS_NAME_PASS
+#undef __PASS_NAME_PASS
+#undef _PASS_NAME_PASS_DATA
+#undef __PASS_NAME_PASS_DATA
+
+#endif /* PASS_NAME */