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 --- lib/bust_spinlocks.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 lib/bust_spinlocks.c (limited to 'lib/bust_spinlocks.c') diff --git a/lib/bust_spinlocks.c b/lib/bust_spinlocks.c new file mode 100644 index 000000000..bfd53972a --- /dev/null +++ b/lib/bust_spinlocks.c @@ -0,0 +1,29 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * lib/bust_spinlocks.c + * + * Provides a minimal bust_spinlocks for architectures which don't + * have one of their own. + * + * bust_spinlocks() clears any spinlocks which would prevent oops, die(), BUG() + * and panic() information from reaching the user. + */ + +#include +#include +#include +#include +#include +#include +#include + +void bust_spinlocks(int yes) +{ + if (yes) { + ++oops_in_progress; + } else { + console_unblank(); + if (--oops_in_progress == 0) + wake_up_klogd(); + } +} -- cgit v1.3.1