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 --- rust/macros/export.rs | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 rust/macros/export.rs (limited to 'rust/macros/export.rs') diff --git a/rust/macros/export.rs b/rust/macros/export.rs new file mode 100644 index 000000000..6d53521f6 --- /dev/null +++ b/rust/macros/export.rs @@ -0,0 +1,25 @@ +// SPDX-License-Identifier: GPL-2.0 + +use proc_macro2::TokenStream; +use quote::quote; + +/// Please see [`crate::export`] for documentation. +pub(crate) fn export(f: syn::ItemFn) -> TokenStream { + let name = &f.sig.ident; + + quote! { + // This verifies that the function has the same signature as the declaration generated by + // bindgen. It makes use of the fact that all branches of an if/else must have the same + // type. + const _: () = { + if true { + ::kernel::bindings::#name + } else { + #name + }; + }; + + #[no_mangle] + #f + } +} -- cgit v1.3.1