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, 32 insertions, 0 deletions

diff --git a/drivers/firmware/broadcom/Kconfig b/drivers/firmware/broadcom/Kconfig
new file mode 100644
index 000000000..8e3d355a6
--- /dev/null
+++ b/drivers/firmware/broadcom/Kconfig
@@ -0,0 +1,32 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config BCM47XX_NVRAM
+	bool "Broadcom NVRAM driver"
+	depends on BCM47XX || ARCH_BCM_5301X || COMPILE_TEST
+	help
+	  Broadcom home routers contain flash partition called "nvram" with all
+	  important hardware configuration as well as some minor user setup.
+	  NVRAM partition contains a text-like data representing name=value
+	  pairs.
+	  This driver provides an easy way to get value of requested parameter.
+	  It simply reads content of NVRAM and parses it. It doesn't control any
+	  hardware part itself.
+
+config BCM47XX_SPROM
+	bool "Broadcom SPROM driver"
+	depends on BCM47XX_NVRAM
+	select GENERIC_NET_UTILS
+	help
+	  Broadcom devices store configuration data in SPROM. Accessing it is
+	  specific to the bus host type, e.g. PCI(e) devices have it mapped in
+	  a PCI BAR.
+	  In case of SoC devices SPROM content is stored on a flash used by
+	  bootloader firmware CFE. This driver provides method to ssb and bcma
+	  drivers to read SPROM on SoC.
+
+config TEE_BNXT_FW
+	tristate "Broadcom BNXT firmware manager"
+	depends on (ARCH_BCM_IPROC && OPTEE) || (COMPILE_TEST && TEE)
+	default ARCH_BCM_IPROC
+	help
+	  This module help to manage firmware on Broadcom BNXT device. The module
+	  registers on tee bus and invoke calls to manage firmware on BNXT device.