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-class-switchtec | 96 +++++++++++++++++++++++++ 1 file changed, 96 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-switchtec (limited to 'Documentation/ABI/testing/sysfs-class-switchtec') diff --git a/Documentation/ABI/testing/sysfs-class-switchtec b/Documentation/ABI/testing/sysfs-class-switchtec new file mode 100644 index 000000000..76c7a661a --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-switchtec @@ -0,0 +1,96 @@ +switchtec - Microsemi Switchtec PCI Switch Management Endpoint + +For details on this subsystem look at Documentation/driver-api/switchtec.rst. + +What: /sys/class/switchtec +Date: 05-Jan-2017 +KernelVersion: v4.11 +Contact: Logan Gunthorpe +Description: The switchtec class subsystem folder. + Each registered switchtec driver is represented by a switchtecX + subfolder (X being an integer >= 0). + + +What: /sys/class/switchtec/switchtec[0-9]+/component_id +Date: 05-Jan-2017 +KernelVersion: v4.11 +Contact: Logan Gunthorpe +Description: Component identifier as stored in the hardware (eg. PM8543) + (read only) +Values: arbitrary string. + + +What: /sys/class/switchtec/switchtec[0-9]+/component_revision +Date: 05-Jan-2017 +KernelVersion: v4.11 +Contact: Logan Gunthorpe +Description: Component revision stored in the hardware (read only) +Values: integer. + + +What: /sys/class/switchtec/switchtec[0-9]+/component_vendor +Date: 05-Jan-2017 +KernelVersion: v4.11 +Contact: Logan Gunthorpe +Description: Component vendor as stored in the hardware (eg. MICROSEM) + (read only) +Values: arbitrary string. + + +What: /sys/class/switchtec/switchtec[0-9]+/device_version +Date: 05-Jan-2017 +KernelVersion: v4.11 +Contact: Logan Gunthorpe +Description: Device version as stored in the hardware (read only) +Values: integer. + + +What: /sys/class/switchtec/switchtec[0-9]+/fw_version +Date: 05-Jan-2017 +KernelVersion: v4.11 +Contact: Logan Gunthorpe +Description: Currently running firmware version (read only) +Values: integer (in hexadecimal). + + +What: /sys/class/switchtec/switchtec[0-9]+/partition +Date: 05-Jan-2017 +KernelVersion: v4.11 +Contact: Logan Gunthorpe +Description: Partition number for this device in the switch (read only) +Values: integer. + + +What: /sys/class/switchtec/switchtec[0-9]+/partition_count +Date: 05-Jan-2017 +KernelVersion: v4.11 +Contact: Logan Gunthorpe +Description: Total number of partitions in the switch (read only) +Values: integer. + + +What: /sys/class/switchtec/switchtec[0-9]+/product_id +Date: 05-Jan-2017 +KernelVersion: v4.11 +Contact: Logan Gunthorpe +Description: Product identifier as stored in the hardware (eg. PSX 48XG3) + (read only) +Values: arbitrary string. + + +What: /sys/class/switchtec/switchtec[0-9]+/product_revision +Date: 05-Jan-2017 +KernelVersion: v4.11 +Contact: Logan Gunthorpe +Description: Product revision stored in the hardware (eg. RevB) + (read only) +Values: arbitrary string. + + +What: /sys/class/switchtec/switchtec[0-9]+/product_vendor +Date: 05-Jan-2017 +KernelVersion: v4.11 +Contact: Logan Gunthorpe +Description: Product vendor as stored in the hardware (eg. MICROSEM) + (read only) +Values: arbitrary string. -- cgit v1.3.1