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, 65 insertions, 0 deletions

diff --git a/drivers/tty/vt/Makefile b/drivers/tty/vt/Makefile
new file mode 100644
index 000000000..ae746dcde
--- /dev/null
+++ b/drivers/tty/vt/Makefile
@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# This file contains the font map for the default (hardware) font
+#
+FONTMAPFILE = cp437.uni
+
+obj-$(CONFIG_VT)			+= vt_ioctl.o vc_screen.o \
+					   selection.o keyboard.o \
+					   vt.o defkeymap.o
+obj-$(CONFIG_CONSOLE_TRANSLATIONS)	+= consolemap.o consolemap_deftbl.o \
+					   ucs.o
+
+# Files generated that shall be removed upon make clean
+clean-files :=	consolemap_deftbl.c defkeymap.c \
+		ucs_width_table.h ucs_recompose_table.h ucs_fallback_table.h
+
+hostprogs += conmakehash
+
+quiet_cmd_conmk = CONMK   $@
+      cmd_conmk = $(obj)/conmakehash $< > $@
+
+$(obj)/consolemap_deftbl.c: $(src)/$(FONTMAPFILE) $(obj)/conmakehash
+	$(call cmd,conmk)
+
+$(obj)/defkeymap.o:  $(obj)/defkeymap.c
+
+# Uncomment if you're changing the keymap and have an appropriate
+# loadkeys version for the map. By default, we'll use the shipped
+# versions.
+# GENERATE_KEYMAP := 1
+
+ifdef GENERATE_KEYMAP
+
+$(obj)/defkeymap.c: $(obj)/%.c: $(src)/%.map
+	loadkeys --mktable --unicode $< > $@
+
+endif
+
+$(obj)/ucs.o:	$(src)/ucs.c $(obj)/ucs_width_table.h \
+		$(obj)/ucs_recompose_table.h $(obj)/ucs_fallback_table.h
+
+# You may uncomment one of those to have the UCS tables be regenerated
+# during the build process. By default the _shipped versions are used.
+#
+#GENERATE_UCS_TABLES := 1
+#GENERATE_UCS_TABLES := 2  # invokes gen_ucs_recompose_table.py with --full
+
+ifdef GENERATE_UCS_TABLES
+
+$(obj)/ucs_width_table.h: $(src)/gen_ucs_width_table.py
+	$(PYTHON3) $< -o $@
+
+ifeq ($(GENERATE_UCS_TABLES),2)
+gen_recomp_arg := --full
+else
+gen_recomp_arg :=
+endif
+
+$(obj)/ucs_recompose_table.h: $(src)/gen_ucs_recompose_table.py
+	$(PYTHON3) $< -o $@ $(gen_recomp_arg)
+
+$(obj)/ucs_fallback_table.h: $(src)/gen_ucs_fallback_table.py
+	$(PYTHON3) $< -o $@
+
+endif