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-uacce | 57 ++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-driver-uacce (limited to 'Documentation/ABI/testing/sysfs-driver-uacce') diff --git a/Documentation/ABI/testing/sysfs-driver-uacce b/Documentation/ABI/testing/sysfs-driver-uacce new file mode 100644 index 000000000..d3f0b8f3c --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-uacce @@ -0,0 +1,57 @@ +What: /sys/class/uacce//api +Date: Feb 2020 +KernelVersion: 5.7 +Contact: linux-accelerators@lists.ozlabs.org +Description: Api of the device + Can be any string and up to userspace to parse. + Application use the api to match the correct driver + +What: /sys/class/uacce//flags +Date: Feb 2020 +KernelVersion: 5.7 +Contact: linux-accelerators@lists.ozlabs.org +Description: Attributes of the device, see UACCE_DEV_xxx flag defined in uacce.h + +What: /sys/class/uacce//available_instances +Date: Feb 2020 +KernelVersion: 5.7 +Contact: linux-accelerators@lists.ozlabs.org +Description: Available instances left of the device + Return -ENODEV if uacce_ops get_available_instances is not provided + +What: /sys/class/uacce//isolate_strategy +Date: Nov 2022 +KernelVersion: 6.1 +Contact: linux-accelerators@lists.ozlabs.org +Description: (RW) A sysfs node that configure the error threshold for the hardware + isolation strategy. This size is a configured integer value, which is the + number of threshold for hardware errors occurred in one hour. The default is 0. + 0 means never isolate the device. The maximum value is 65535. You can write + a number of threshold based on your hardware. + +What: /sys/class/uacce//isolate +Date: Nov 2022 +KernelVersion: 6.1 +Contact: linux-accelerators@lists.ozlabs.org +Description: (R) A sysfs node that read the device isolated state. The value 1 + means the device is unavailable. The 0 means the device is + available. + +What: /sys/class/uacce//algorithms +Date: Feb 2020 +KernelVersion: 5.7 +Contact: linux-accelerators@lists.ozlabs.org +Description: Algorithms supported by this accelerator, separated by new line. + Can be any string and up to userspace to parse. + +What: /sys/class/uacce//region_mmio_size +Date: Feb 2020 +KernelVersion: 5.7 +Contact: linux-accelerators@lists.ozlabs.org +Description: Size (bytes) of mmio region queue file + +What: /sys/class/uacce//region_dus_size +Date: Feb 2020 +KernelVersion: 5.7 +Contact: linux-accelerators@lists.ozlabs.org +Description: Size (bytes) of dus region queue file -- cgit v1.3.1