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, 92 insertions, 0 deletions

diff --git a/arch/arm/boot/Makefile b/arch/arm/boot/Makefile
new file mode 100644
index 000000000..ba9b9a802
--- /dev/null
+++ b/arch/arm/boot/Makefile
@@ -0,0 +1,92 @@
+#
+# arch/arm/boot/Makefile
+#
+# This file is included by the global makefile so that you can add your own
+# architecture-specific flags and dependencies.
+#
+# This file is subject to the terms and conditions of the GNU General Public
+# License.  See the file "COPYING" in the main directory of this archive
+# for more details.
+#
+# Copyright (C) 1995-2002 Russell King
+#
+OBJCOPYFLAGS	:=-O binary -R .comment -S
+
+#   ZRELADDR == virt_to_phys(PAGE_OFFSET + TEXT_OFFSET)
+ifdef CONFIG_PHYS_OFFSET
+add_hex = $(shell printf 0x%x $$(( $(1) + $(2) )) )
+ZRELADDR    := $(call add_hex, $(CONFIG_PHYS_OFFSET), $(TEXT_OFFSET))
+endif
+
+PHYS_OFFSET := $(CONFIG_PHYS_OFFSET)
+export ZRELADDR PARAMS_PHYS PHYS_OFFSET
+
+targets := Image zImage xipImage bootpImage uImage
+
+ifeq ($(CONFIG_XIP_KERNEL),y)
+
+cmd_deflate_xip_data = $(CONFIG_SHELL) -c '$(src)/deflate_xip_data.sh $< $@'
+
+ifeq ($(CONFIG_XIP_DEFLATED_DATA),y)
+quiet_cmd_mkxip = XIPZ    $@
+cmd_mkxip = $(cmd_objcopy) && $(cmd_deflate_xip_data)
+else
+quiet_cmd_mkxip = $(quiet_cmd_objcopy)
+cmd_mkxip = $(cmd_objcopy)
+endif
+
+$(obj)/xipImage: vmlinux FORCE
+	$(call if_changed,mkxip)
+	@$(kecho) '  Physical Address of xipImage: $(CONFIG_XIP_PHYS_ADDR)'
+
+$(obj)/Image $(obj)/zImage: FORCE
+	@echo 'Kernel configured for XIP (CONFIG_XIP_KERNEL=y)'
+	@echo 'Only the xipImage target is available in this case'
+	@false
+
+else
+
+$(obj)/xipImage: FORCE
+	@echo 'Kernel not configured for XIP (CONFIG_XIP_KERNEL!=y)'
+	@false
+
+$(obj)/Image: vmlinux FORCE
+	$(call if_changed,objcopy)
+
+$(obj)/compressed/vmlinux: $(obj)/Image FORCE
+	$(Q)$(MAKE) $(build)=$(obj)/compressed $@
+
+$(obj)/zImage:	$(obj)/compressed/vmlinux FORCE
+	$(call if_changed,objcopy)
+
+endif
+
+ifneq ($(LOADADDR),)
+  UIMAGE_LOADADDR=$(LOADADDR)
+else
+  ifeq ($(CONFIG_ZBOOT_ROM),y)
+    UIMAGE_LOADADDR=$(CONFIG_ZBOOT_ROM_TEXT)
+  else
+    UIMAGE_LOADADDR=$(ZRELADDR)
+  endif
+endif
+
+check_for_multiple_loadaddr = \
+if [ $(words $(UIMAGE_LOADADDR)) -ne 1 ]; then \
+	echo 'multiple (or no) load addresses: $(UIMAGE_LOADADDR)'; \
+	echo 'This is incompatible with uImages'; \
+	echo 'Specify LOADADDR on the commandline to build an uImage'; \
+	false; \
+fi
+
+$(obj)/uImage:	$(obj)/zImage FORCE
+	@$(check_for_multiple_loadaddr)
+	$(call if_changed,uimage)
+
+$(obj)/bootp/bootp: $(obj)/zImage FORCE
+	$(Q)$(MAKE) $(build)=$(obj)/bootp $@
+
+$(obj)/bootpImage: $(obj)/bootp/bootp FORCE
+	$(call if_changed,objcopy)
+
+subdir-	    := bootp compressed dts