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 --- include/kunit/visibility.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 include/kunit/visibility.h (limited to 'include/kunit/visibility.h') diff --git a/include/kunit/visibility.h b/include/kunit/visibility.h new file mode 100644 index 000000000..7c34c8ffc --- /dev/null +++ b/include/kunit/visibility.h @@ -0,0 +1,33 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * KUnit API to allow symbols to be conditionally visible during KUnit + * testing + * + * Copyright (C) 2022, Google LLC. + * Author: Rae Moar + */ + +#ifndef _KUNIT_VISIBILITY_H +#define _KUNIT_VISIBILITY_H + +#if IS_ENABLED(CONFIG_KUNIT) + /** + * VISIBLE_IF_KUNIT - A macro that sets symbols to be static if + * CONFIG_KUNIT is not enabled. Otherwise if CONFIG_KUNIT is enabled + * there is no change to the symbol definition. + */ + #define VISIBLE_IF_KUNIT + /** + * EXPORT_SYMBOL_IF_KUNIT(symbol) - Exports symbol into + * EXPORTED_FOR_KUNIT_TESTING namespace only if CONFIG_KUNIT is + * enabled. Must use MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING") + * in test file in order to use symbols. + * @symbol: the symbol identifier to export + */ + #define EXPORT_SYMBOL_IF_KUNIT(symbol) EXPORT_SYMBOL_NS(symbol, "EXPORTED_FOR_KUNIT_TESTING") +#else + #define VISIBLE_IF_KUNIT static + #define EXPORT_SYMBOL_IF_KUNIT(symbol) +#endif + +#endif /* _KUNIT_VISIBILITY_H */ -- cgit v1.3.1