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 --- samples/rust/rust_minimal.rs | 56 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 samples/rust/rust_minimal.rs (limited to 'samples/rust/rust_minimal.rs') diff --git a/samples/rust/rust_minimal.rs b/samples/rust/rust_minimal.rs new file mode 100644 index 000000000..8c910d314 --- /dev/null +++ b/samples/rust/rust_minimal.rs @@ -0,0 +1,56 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Rust minimal sample. + +use kernel::prelude::*; + +module! { + type: RustMinimal, + name: "rust_minimal", + authors: ["Rust for Linux Contributors"], + description: "Rust minimal sample", + license: "GPL", + params: { + test_parameter: i64 { + default: 1, + description: "This parameter has a default of 1", + }, + test_bool_parameter: bool { + default: false, + description: "This boolean parameter defaults to false", + }, + }, +} + +struct RustMinimal { + numbers: KVec, +} + +impl kernel::Module for RustMinimal { + fn init(_module: &'static ThisModule) -> Result { + pr_info!("Rust minimal sample (init)\n"); + pr_info!("Am I built-in? {}\n", !cfg!(MODULE)); + pr_info!( + "test_parameter: {}\n", + module_parameters::test_parameter.value() + ); + pr_info!( + "test_bool_parameter: {}\n", + module_parameters::test_bool_parameter.value() + ); + + let mut numbers = KVec::new(); + numbers.push(72, GFP_KERNEL)?; + numbers.push(108, GFP_KERNEL)?; + numbers.push(200, GFP_KERNEL)?; + + Ok(RustMinimal { numbers }) + } +} + +impl Drop for RustMinimal { + fn drop(&mut self) { + pr_info!("My numbers are {:?}\n", self.numbers); + pr_info!("Rust minimal sample (exit)\n"); + } +} -- cgit v1.3.1