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, 43 insertions, 0 deletions

diff --git a/drivers/block/Makefile b/drivers/block/Makefile
new file mode 100644
index 000000000..2d8096eb8
--- /dev/null
+++ b/drivers/block/Makefile
@@ -0,0 +1,43 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the kernel block device drivers.
+#
+# 12 June 2000, Christoph Hellwig <hch@infradead.org>
+# Rewritten to use lists instead of if-statements.
+# 
+
+# needed for trace events
+ccflags-y				+= -I$(src)
+
+obj-$(CONFIG_MAC_FLOPPY)	+= swim3.o
+obj-$(CONFIG_BLK_DEV_SWIM)	+= swim_mod.o
+obj-$(CONFIG_BLK_DEV_FD)	+= floppy.o
+obj-$(CONFIG_AMIGA_FLOPPY)	+= amiflop.o
+obj-$(CONFIG_PS3_DISK)		+= ps3disk.o
+obj-$(CONFIG_PS3_VRAM)		+= ps3vram.o
+obj-$(CONFIG_ATARI_FLOPPY)	+= ataflop.o
+obj-$(CONFIG_AMIGA_Z2RAM)	+= z2ram.o
+obj-$(CONFIG_N64CART)		+= n64cart.o
+obj-$(CONFIG_BLK_DEV_RAM)	+= brd.o
+obj-$(CONFIG_BLK_DEV_LOOP)	+= loop.o
+obj-$(CONFIG_SUNVDC)		+= sunvdc.o
+
+obj-$(CONFIG_BLK_DEV_NBD)	+= nbd.o
+obj-$(CONFIG_VIRTIO_BLK)	+= virtio_blk.o
+
+obj-$(CONFIG_XEN_BLKDEV_FRONTEND)	+= xen-blkfront.o
+obj-$(CONFIG_XEN_BLKDEV_BACKEND)	+= xen-blkback/
+obj-$(CONFIG_BLK_DEV_DRBD)     += drbd/
+obj-$(CONFIG_BLK_DEV_RBD)     += rbd.o
+obj-$(CONFIG_BLK_DEV_PCIESSD_MTIP32XX)	+= mtip32xx/
+
+obj-$(CONFIG_ZRAM) += zram/
+obj-$(CONFIG_BLK_DEV_RNBD)	+= rnbd/
+
+obj-$(CONFIG_BLK_DEV_NULL_BLK)	+= null_blk/
+obj-$(CONFIG_BLK_DEV_RUST_NULL) += rnull/
+
+obj-$(CONFIG_BLK_DEV_UBLK)			+= ublk_drv.o
+obj-$(CONFIG_BLK_DEV_ZONED_LOOP) += zloop.o
+
+swim_mod-y	:= swim.o swim_asm.o