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, 52 insertions, 0 deletions

diff --git a/tools/scripts/Makefile.arch b/tools/scripts/Makefile.arch
new file mode 100644
index 000000000..ed5f008d4
--- /dev/null
+++ b/tools/scripts/Makefile.arch
@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: GPL-2.0
+HOSTARCH := $(shell uname -m | sed -e s/i.86/x86/ -e s/x86_64/x86/ \
+                                  -e s/sun4u/sparc/ -e s/sparc64/sparc/ \
+                                  -e /arm64/!s/arm.*/arm/ -e s/sa110/arm/ \
+                                  -e s/s390x/s390/ -e s/parisc64/parisc/ \
+                                  -e s/ppc.*/powerpc/ -e s/mips.*/mips/ \
+                                  -e s/sh[234].*/sh/ -e s/aarch64.*/arm64/ \
+                                  -e s/riscv.*/riscv/ -e s/loongarch.*/loongarch/)
+
+ifeq ($(strip $(ARCH)),)
+override ARCH := $(HOSTARCH)
+endif
+
+SRCARCH := $(ARCH)
+
+# Additional ARCH settings for x86
+ifeq ($(ARCH),i386)
+        SRCARCH := x86
+endif
+ifeq ($(ARCH),x86_64)
+        SRCARCH := x86
+endif
+
+# Additional ARCH settings for sparc
+ifeq ($(ARCH),sparc32)
+       SRCARCH := sparc
+endif
+ifeq ($(ARCH),sparc64)
+       SRCARCH := sparc
+endif
+
+# Additional ARCH settings for loongarch
+ifeq ($(ARCH),loongarch32)
+       SRCARCH := loongarch
+endif
+
+ifeq ($(ARCH),loongarch64)
+       SRCARCH := loongarch
+endif
+
+# Probe for __LP64__ only when the compiler is installed: this runs at
+# parse time for every target, including ones that never compile, e.g.
+# install-build-deps, and would otherwise spew "gcc: not found" when the
+# compiler is not yet installed. Only the first word of CC is consulted,
+# as CC may carry arguments, e.g. 'ccache gcc'. When the guard fails it
+# prints nothing, leaving LP64 unset, as if the probe had failed.
+LP64 := $(shell if command -v $(firstword ${CC}) >/dev/null 2>&1; then echo __LP64__ | ${CC} ${CFLAGS} -E -x c -; fi | tail -n 1)
+ifeq ($(LP64), 1)
+  IS_64_BIT := 1
+else
+  IS_64_BIT := 0
+endif