From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() 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 Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- Documentation/ABI/testing/sysfs-driver-xdata | 49 ++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-driver-xdata (limited to 'Documentation/ABI/testing/sysfs-driver-xdata') diff --git a/Documentation/ABI/testing/sysfs-driver-xdata b/Documentation/ABI/testing/sysfs-driver-xdata new file mode 100644 index 000000000..f574e8e6d --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-xdata @@ -0,0 +1,49 @@ +What: /sys/class/misc/drivers/dw-xdata-pcie./write +Date: April 2021 +KernelVersion: 5.13 +Contact: Gustavo Pimentel +Description: Allows the user to enable the PCIe traffic generator which + will create write TLPs frames - from the Root Complex to the + Endpoint direction or to disable the PCIe traffic generator + in all directions. + + Write y/1/on to enable, n/0/off to disable + + Usage e.g. + echo 1 > /sys/class/misc/dw-xdata-pcie./write + or + echo 0 > /sys/class/misc/dw-xdata-pcie./write + + The user can read the current PCIe link throughput generated + through this generator in MB/s. + + Usage e.g. + cat /sys/class/misc/dw-xdata-pcie./write + 204 + + The file is read and write. + +What: /sys/class/misc/dw-xdata-pcie./read +Date: April 2021 +KernelVersion: 5.13 +Contact: Gustavo Pimentel +Description: Allows the user to enable the PCIe traffic generator which + will create read TLPs frames - from the Endpoint to the Root + Complex direction or to disable the PCIe traffic generator + in all directions. + + Write y/1/on to enable, n/0/off to disable + + Usage e.g. + echo 1 > /sys/class/misc/dw-xdata-pcie./read + or + echo 0 > /sys/class/misc/dw-xdata-pcie./read + + The user can read the current PCIe link throughput generated + through this generator in MB/s. + + Usage e.g. + cat /sys/class/misc/dw-xdata-pcie./read + 199 + + The file is read and write. -- cgit v1.3.1