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, 72 insertions, 0 deletions

diff --git a/drivers/hid/hid-cherry.c b/drivers/hid/hid-cherry.c
new file mode 100644
index 000000000..a504632fe
--- /dev/null
+++ b/drivers/hid/hid-cherry.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for some cherry "special" devices
+ *
+ *  Copyright (c) 1999 Andreas Gal
+ *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
+ *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
+ *  Copyright (c) 2006-2007 Jiri Kosina
+ *  Copyright (c) 2008 Jiri Slaby
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+/*
+ * Cherry Cymotion keyboard have an invalid HID report descriptor,
+ * that needs fixing before we can parse it.
+ */
+static const __u8 *ch_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	if (*rsize >= 18 && rdesc[11] == 0x3c && rdesc[12] == 0x02) {
+		hid_info(hdev, "fixing up Cherry Cymotion report descriptor\n");
+		rdesc[11] = rdesc[16] = 0xff;
+		rdesc[12] = rdesc[17] = 0x03;
+	}
+	return rdesc;
+}
+
+#define ch_map_key_clear(c)	hid_map_usage_clear(hi, usage, bit, max, \
+					EV_KEY, (c))
+static int ch_input_mapping(struct hid_device *hdev, struct hid_input *hi,
+		struct hid_field *field, struct hid_usage *usage,
+		unsigned long **bit, int *max)
+{
+	if ((usage->hid & HID_USAGE_PAGE) != HID_UP_CONSUMER)
+		return 0;
+
+	switch (usage->hid & HID_USAGE) {
+	case 0x301: ch_map_key_clear(KEY_PROG1);	break;
+	case 0x302: ch_map_key_clear(KEY_PROG2);	break;
+	case 0x303: ch_map_key_clear(KEY_PROG3);	break;
+	default:
+		return 0;
+	}
+
+	return 1;
+}
+
+static const struct hid_device_id ch_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CHERRY, USB_DEVICE_ID_CHERRY_CYMOTION) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CHERRY, USB_DEVICE_ID_CHERRY_CYMOTION_SOLAR) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, ch_devices);
+
+static struct hid_driver ch_driver = {
+	.name = "cherry",
+	.id_table = ch_devices,
+	.report_fixup = ch_report_fixup,
+	.input_mapping = ch_input_mapping,
+};
+module_hid_driver(ch_driver);
+
+MODULE_DESCRIPTION("HID driver for some cherry \"special\" devices");
+MODULE_LICENSE("GPL");