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, 120 insertions, 0 deletions

diff --git a/arch/alpha/boot/Makefile b/arch/alpha/boot/Makefile
new file mode 100644
index 000000000..d8dba85e6
--- /dev/null
+++ b/arch/alpha/boot/Makefile
@@ -0,0 +1,120 @@
+#
+# arch/alpha/boot/Makefile
+#
+# 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) 1994 by Linus Torvalds
+#
+
+hostprogs	:= tools/mkbb tools/objstrip
+targets		:= vmlinux.gz vmlinux \
+		   vmlinux.nh tools/lxboot tools/bootlx tools/bootph \
+		   tools/bootpzh bootloader bootpheader bootpzheader 
+OBJSTRIP	:= $(obj)/tools/objstrip
+
+KBUILD_HOSTCFLAGS := -Wall -I$(objtree)/usr/include
+BOOTCFLAGS	+= -I$(objtree)/$(obj) -I$(srctree)/$(obj)
+
+# SRM bootable image.  Copy to offset 512 of a partition.
+$(obj)/bootimage: $(addprefix $(obj)/tools/,mkbb lxboot bootlx) $(obj)/vmlinux.nh
+	( cat $(obj)/tools/lxboot $(obj)/tools/bootlx $(obj)/vmlinux.nh ) > $@ 
+	$(obj)/tools/mkbb $@ $(obj)/tools/lxboot
+	@echo '  Bootimage $@ is ready'
+
+# BOOTP bootable image.  Define INITRD during make to append initrd image.
+$(obj)/bootpfile: $(obj)/tools/bootph $(obj)/vmlinux.nh
+	cat $(obj)/tools/bootph $(obj)/vmlinux.nh > $@
+ifdef INITRD
+	cat $(INITRD) >> $@
+endif
+
+# Compressed kernel BOOTP bootable image.
+# Define INITRD during make to append initrd image.
+$(obj)/bootpzfile: $(obj)/tools/bootpzh $(obj)/vmlinux.nh.gz
+	cat $(obj)/tools/bootpzh $(obj)/vmlinux.nh.gz > $@
+ifdef INITRD
+	cat $(INITRD) >> $@
+endif
+
+# Compressed kernel image
+$(obj)/vmlinux.gz: $(obj)/vmlinux FORCE
+	$(call if_changed,gzip)
+	@echo '  Kernel $@ is ready'
+
+$(obj)/main.o: $(obj)/ksize.h
+$(obj)/bootp.o: $(obj)/ksize.h
+$(obj)/bootpz.o: $(obj)/kzsize.h
+
+$(obj)/ksize.h: $(obj)/vmlinux.nh FORCE
+	echo "#define KERNEL_SIZE `ls -l $(obj)/vmlinux.nh | awk '{print $$5}'`" > $@T
+ifdef INITRD
+	[ -f $(INITRD) ] || exit 1
+	echo "#define INITRD_IMAGE_SIZE `ls -l $(INITRD) | awk '{print $$5}'`" >> $@T
+endif
+	cmp -s $@T $@ || mv -f $@T $@
+	rm -f $@T
+
+$(obj)/kzsize.h: $(obj)/vmlinux.nh.gz FORCE
+	echo "#define KERNEL_SIZE `ls -l $(obj)/vmlinux.nh | awk '{print $$5}'`" > $@T
+	echo "#define KERNEL_Z_SIZE `ls -l $(obj)/vmlinux.nh.gz | awk '{print $$5}'`" >> $@T
+ifdef INITRD
+	[ -f $(INITRD) ] || exit 1
+	echo "#define INITRD_IMAGE_SIZE `ls -l $(INITRD) | awk '{print $$5}'`" >> $@T
+endif
+	cmp -s $@T $@ || mv -f $@T $@
+	rm -f $@T
+
+quiet_cmd_strip = STRIP  $@
+      cmd_strip = $(STRIP) -o $@ $<
+
+$(obj)/vmlinux: vmlinux FORCE
+	$(call if_changed,strip)
+
+quiet_cmd_objstrip = OBJSTRIP $@
+      cmd_objstrip = $(OBJSTRIP) $(OSFLAGS_$(@F)) $< $@
+
+OSFLAGS_vmlinux.nh	:= -v
+OSFLAGS_lxboot		:= -p
+OSFLAGS_bootlx		:= -vb
+OSFLAGS_bootph		:= -vb
+OSFLAGS_bootpzh		:= -vb
+
+$(obj)/vmlinux.nh: vmlinux $(OBJSTRIP) FORCE
+	$(call if_changed,objstrip)
+
+$(obj)/vmlinux.nh.gz: $(obj)/vmlinux.nh FORCE
+	$(call if_changed,gzip)
+
+$(obj)/tools/lxboot: $(obj)/bootloader $(OBJSTRIP) FORCE
+	$(call if_changed,objstrip)
+
+$(obj)/tools/bootlx: $(obj)/bootloader $(OBJSTRIP) FORCE
+	$(call if_changed,objstrip)
+
+$(obj)/tools/bootph: $(obj)/bootpheader $(OBJSTRIP) FORCE
+	$(call if_changed,objstrip)
+
+$(obj)/tools/bootpzh: $(obj)/bootpzheader $(OBJSTRIP) FORCE
+	$(call if_changed,objstrip)
+
+LDFLAGS_bootloader   := -static -T # -N -relax
+LDFLAGS_bootloader   := -static -T # -N -relax
+LDFLAGS_bootpheader  := -static -T # -N -relax
+LDFLAGS_bootpzheader := -static -T # -N -relax
+
+OBJ_bootlx   := $(obj)/head.o $(obj)/stdio.o $(obj)/main.o
+OBJ_bootph   := $(obj)/head.o $(obj)/stdio.o $(obj)/bootp.o
+OBJ_bootpzh  := $(obj)/head.o $(obj)/stdio.o $(obj)/bootpz.o $(obj)/misc.o
+
+$(obj)/bootloader: $(obj)/bootloader.lds $(OBJ_bootlx) $(LIBS_Y) FORCE
+	$(call if_changed,ld)
+
+$(obj)/bootpheader: $(obj)/bootloader.lds $(OBJ_bootph) $(LIBS_Y) FORCE
+	$(call if_changed,ld)
+
+$(obj)/bootpzheader: $(obj)/bootloader.lds $(OBJ_bootpzh) $(LIBS_Y) FORCE
+	$(call if_changed,ld)
+
+$(obj)/misc.o: lib/inflate.c