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/debugfs-moxtet | 35 ++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 Documentation/ABI/testing/debugfs-moxtet (limited to 'Documentation/ABI/testing/debugfs-moxtet') diff --git a/Documentation/ABI/testing/debugfs-moxtet b/Documentation/ABI/testing/debugfs-moxtet new file mode 100644 index 000000000..637d8587d --- /dev/null +++ b/Documentation/ABI/testing/debugfs-moxtet @@ -0,0 +1,35 @@ +What: /sys/kernel/debug/moxtet/input +Date: March 2019 +KernelVersion: 5.3 +Contact: Marek Behún +Description: (Read) Read input from the shift registers, in hexadecimal. + Returns N+1 bytes, where N is the number of Moxtet connected + modules. The first byte is from the CPU board itself. + + Example:: + + 101214 + + == ======================================= + 10 CPU board with SD card + 12 2 = PCIe module, 1 = IRQ not active + 14 4 = Peridot module, 1 = IRQ not active + == ======================================= + +What: /sys/kernel/debug/moxtet/output +Date: March 2019 +KernelVersion: 5.3 +Contact: Marek Behún +Description: (RW) Read last written value to the shift registers, in + hexadecimal, or write values to the shift registers, also + in hexadecimal. + + Example:: + + 0102 + + == ================================================ + 01 01 was last written, or is to be written, to the + first module's shift register + 02 the same for second module + == ================================================ -- cgit v1.3.1