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, 37 insertions, 0 deletions

diff --git a/drivers/mtd/maps/Makefile b/drivers/mtd/maps/Makefile
new file mode 100644
index 000000000..01745eca1
--- /dev/null
+++ b/drivers/mtd/maps/Makefile
@@ -0,0 +1,37 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# linux/drivers/maps/Makefile
+#
+
+ifeq ($(CONFIG_MTD_COMPLEX_MAPPINGS),y)
+obj-$(CONFIG_MTD)		+= map_funcs.o
+endif
+
+# Chip mappings
+obj-$(CONFIG_MTD_CFI_FLAGADM)	+= cfi_flagadm.o
+obj-$(CONFIG_MTD_DC21285)	+= dc21285.o
+obj-$(CONFIG_MTD_L440GX)	+= l440gx.o
+obj-$(CONFIG_MTD_AMD76XROM)	+= amd76xrom.o
+obj-$(CONFIG_MTD_ESB2ROM)	+= esb2rom.o
+obj-$(CONFIG_MTD_ICHXROM)	+= ichxrom.o
+obj-$(CONFIG_MTD_CK804XROM)	+= ck804xrom.o
+obj-$(CONFIG_MTD_TSUNAMI)	+= tsunami_flash.o
+obj-$(CONFIG_MTD_PXA2XX)	+= pxa2xx-flash.o
+obj-$(CONFIG_MTD_PHYSMAP)	+= physmap.o
+physmap-y			:= physmap-core.o
+physmap-$(CONFIG_MTD_PHYSMAP_VERSATILE) += physmap-versatile.o
+physmap-$(CONFIG_MTD_PHYSMAP_GEMINI) += physmap-gemini.o
+physmap-$(CONFIG_MTD_PHYSMAP_IXP4XX) += physmap-ixp4xx.o
+obj-$(CONFIG_MTD_PISMO)		+= pismo.o
+obj-$(CONFIG_MTD_PCMCIA)	+= pcmciamtd.o
+obj-$(CONFIG_MTD_SA1100)	+= sa1100-flash.o
+obj-$(CONFIG_MTD_SBC_GXX)	+= sbc_gxx.o
+obj-$(CONFIG_MTD_SUN_UFLASH)	+= sun_uflash.o
+obj-$(CONFIG_MTD_SCx200_DOCFLASH)+= scx200_docflash.o
+obj-$(CONFIG_MTD_SOLUTIONENGINE)+= solutionengine.o
+obj-$(CONFIG_MTD_PCI)		+= pci.o
+obj-$(CONFIG_MTD_UCLINUX)	+= uclinux.o
+obj-$(CONFIG_MTD_SCB2_FLASH)	+= scb2_flash.o
+obj-$(CONFIG_MTD_PLATRAM)	+= plat-ram.o
+obj-$(CONFIG_MTD_VMU)		+= vmu-flash.o
+obj-$(CONFIG_MTD_LANTIQ)	+= lantiq-flash.o