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, 50 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
new file mode 100644
index 000000000..0834a9a12
--- /dev/null
+++ b/arch/powerpc/sysdev/Makefile
@@ -0,0 +1,50 @@
+# SPDX-License-Identifier: GPL-2.0
+
+mpic-msi-obj-$(CONFIG_PCI_MSI)	+= mpic_msi.o mpic_u3msi.o
+obj-$(CONFIG_MPIC)		+= mpic.o $(mpic-msi-obj-y)
+obj-$(CONFIG_MPIC_TIMER)        += mpic_timer.o
+obj-$(CONFIG_FSL_MPIC_TIMER_WAKEUP)	+= fsl_mpic_timer_wakeup.o
+mpic-msgr-obj-$(CONFIG_MPIC_MSGR)	+= mpic_msgr.o
+obj-$(CONFIG_MPIC)		+= mpic.o $(mpic-msi-obj-y) $(mpic-msgr-obj-y)
+obj-$(CONFIG_PPC_EPAPR_HV_PIC)	+= ehv_pic.o
+fsl-msi-obj-$(CONFIG_PCI_MSI)	+= fsl_msi.o
+obj-$(CONFIG_PPC_MSI_BITMAP)	+= msi_bitmap.o
+
+obj-$(CONFIG_PPC_MPC106)	+= grackle.o
+obj-$(CONFIG_PPC_DCR_NATIVE)	+= dcr-low.o
+obj-$(CONFIG_U3_DART)		+= dart_iommu.o
+obj-$(CONFIG_MMIO_NVRAM)	+= mmio_nvram.o
+obj-$(CONFIG_FSL_SOC)		+= fsl_soc.o fsl_mpic_err.o
+obj-$(CONFIG_FSL_PCI)		+= fsl_pci.o $(fsl-msi-obj-y)
+obj-$(CONFIG_FSL_PMC)		+= fsl_pmc.o
+obj-$(CONFIG_FSL_CORENET_RCPM)	+= fsl_rcpm.o
+obj-$(CONFIG_FSL_LBC)		+= fsl_lbc.o
+obj-$(CONFIG_FSL_GTM)		+= fsl_gtm.o
+obj-$(CONFIG_FSL_RIO)		+= fsl_rio.o fsl_rmu.o
+obj-$(CONFIG_TSI108_BRIDGE)	+= tsi108_pci.o tsi108_dev.o
+obj-$(CONFIG_RTC_DRV_CMOS)	+= rtc_cmos_setup.o
+
+obj-$(CONFIG_PPC_INDIRECT_PCI)	+= indirect_pci.o
+obj-$(CONFIG_PPC_I8259)		+= i8259.o
+obj-$(CONFIG_IPIC)		+= ipic.o
+obj-$(CONFIG_OF_RTC)		+= of_rtc.o
+
+obj-$(CONFIG_CPM)		+= cpm_common.o
+obj-$(CONFIG_CPM2)		+= cpm2.o cpm2_pic.o cpm_gpio.o
+obj-$(CONFIG_8xx_GPIO)		+= cpm_gpio.o
+obj-$(CONFIG_QUICC_ENGINE)	+= cpm_common.o
+obj-$(CONFIG_PPC_DCR)		+= dcr.o
+
+obj-$(CONFIG_PPC_MPC512x)	+= mpc5xxx_clocks.o
+obj-$(CONFIG_PPC_MPC52xx)	+= mpc5xxx_clocks.o
+
+ifdef CONFIG_SUSPEND
+obj-$(CONFIG_PPC_BOOK3S_32)	+= 6xx-suspend.o
+endif
+
+obj-$(CONFIG_PPC_EARLY_DEBUG_MEMCONS)	+= udbg_memcons.o
+
+obj-$(CONFIG_PPC_XICS)		+= xics/
+obj-$(CONFIG_PPC_XIVE)		+= xive/
+
+obj-$(CONFIG_GE_FPGA)		+= ge/