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/bcd.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) create mode 100644 lib/bcd.c (limited to 'lib/bcd.c') diff --git a/lib/bcd.c b/lib/bcd.c new file mode 100644 index 000000000..c5e79ba9c --- /dev/null +++ b/lib/bcd.c @@ -0,0 +1,17 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include + +unsigned _bcd2bin(unsigned char val) +{ + return (val & 0x0f) + (val >> 4) * 10; +} +EXPORT_SYMBOL(_bcd2bin); + +unsigned char _bin2bcd(unsigned val) +{ + const unsigned int t = (val * 103) >> 10; + + return (t << 4) | (val - t * 10); +} +EXPORT_SYMBOL(_bin2bcd); -- cgit v1.3.1