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, 30 insertions, 0 deletions

diff --git a/drivers/net/dsa/Makefile b/drivers/net/dsa/Makefile
new file mode 100644
index 000000000..6ceb78a75
--- /dev/null
+++ b/drivers/net/dsa/Makefile
@@ -0,0 +1,30 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_NET_DSA_BCM_SF2)	+= bcm-sf2.o
+bcm-sf2-objs			:= bcm_sf2.o bcm_sf2_cfp.o
+obj-$(CONFIG_NET_DSA_LOOP)	+= dsa_loop.o
+obj-$(CONFIG_NET_DSA_KS8995) 	+= ks8995.o
+obj-$(CONFIG_NET_DSA_MT7530)	+= mt7530.o
+obj-$(CONFIG_NET_DSA_MT7530_MDIO) += mt7530-mdio.o
+obj-$(CONFIG_NET_DSA_MT7530_MMIO) += mt7530-mmio.o
+obj-$(CONFIG_NET_DSA_MT7628) += mt7628.o
+obj-$(CONFIG_NET_DSA_MV88E6060) += mv88e6060.o
+obj-$(CONFIG_NET_DSA_RZN1_A5PSW) += rzn1_a5psw.o
+obj-$(CONFIG_NET_DSA_SMSC_LAN9303) += lan9303-core.o
+obj-$(CONFIG_NET_DSA_SMSC_LAN9303_I2C) += lan9303_i2c.o
+obj-$(CONFIG_NET_DSA_SMSC_LAN9303_MDIO) += lan9303_mdio.o
+obj-$(CONFIG_NET_DSA_VITESSE_VSC73XX) += vitesse-vsc73xx-core.o
+obj-$(CONFIG_NET_DSA_VITESSE_VSC73XX_PLATFORM) += vitesse-vsc73xx-platform.o
+obj-$(CONFIG_NET_DSA_VITESSE_VSC73XX_SPI) += vitesse-vsc73xx-spi.o
+obj-$(CONFIG_NET_DSA_YT921X) += yt921x.o
+obj-y				+= b53/
+obj-y				+= hirschmann/
+obj-y				+= lantiq/
+obj-y				+= microchip/
+obj-y				+= mv88e6xxx/
+obj-y				+= mxl862xx/
+obj-y				+= netc/
+obj-y				+= ocelot/
+obj-y				+= qca/
+obj-y				+= realtek/
+obj-y				+= sja1105/
+obj-y				+= xrs700x/