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, 56 insertions, 0 deletions

diff --git a/drivers/cache/Kconfig b/drivers/cache/Kconfig
new file mode 100644
index 000000000..1518449d4
--- /dev/null
+++ b/drivers/cache/Kconfig
@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: GPL-2.0
+
+menuconfig CACHEMAINT_FOR_DMA
+	bool "Cache management for noncoherent DMA"
+	depends on RISCV
+	default y
+	help
+	  These drivers implement support for noncoherent DMA master devices
+	  on platforms that lack the standard CPU interfaces for this.
+
+if CACHEMAINT_FOR_DMA
+
+config AX45MP_L2_CACHE
+	bool "Andes Technology AX45MP L2 Cache controller"
+	select RISCV_NONSTANDARD_CACHE_OPS
+	help
+	  Support for the L2 cache controller on Andes Technology AX45MP platforms.
+
+config SIFIVE_CCACHE
+	bool "Sifive Composable Cache controller"
+	depends on ARCH_SIFIVE || ARCH_STARFIVE
+	help
+	  Support for the composable cache controller on SiFive platforms.
+
+config STARFIVE_STARLINK_CACHE
+	bool "StarFive StarLink Cache controller"
+	depends on ARCH_STARFIVE
+	depends on 64BIT
+	select RISCV_DMA_NONCOHERENT
+	select RISCV_NONSTANDARD_CACHE_OPS
+	help
+	  Support for the StarLink cache controller IP from StarFive.
+
+endif #CACHEMAINT_FOR_DMA
+
+menuconfig CACHEMAINT_FOR_HOTPLUG
+	bool "Cache management for memory hot plug like operations"
+	depends on GENERIC_CPU_CACHE_MAINTENANCE
+	help
+	  These drivers implement cache management for flows where it is necessary
+	  to flush data from all host caches.
+
+if CACHEMAINT_FOR_HOTPLUG
+
+config HISI_SOC_HHA
+	tristate "HiSilicon Hydra Home Agent (HHA) device driver"
+	depends on (ARM64 && ACPI) || COMPILE_TEST
+	help
+	  The Hydra Home Agent (HHA) is responsible for cache coherency
+	  on the SoC. This drivers enables the cache maintenance functions of
+	  the HHA.
+
+	  This driver can be built as a module. If so, the module will be
+	  called hisi_soc_hha.
+
+endif #CACHEMAINT_FOR_HOTPLUG