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 --- drivers/rtc/rtc-generic.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 drivers/rtc/rtc-generic.c (limited to 'drivers/rtc/rtc-generic.c') diff --git a/drivers/rtc/rtc-generic.c b/drivers/rtc/rtc-generic.c new file mode 100644 index 000000000..89ae78e93 --- /dev/null +++ b/drivers/rtc/rtc-generic.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* rtc-generic: RTC driver using the generic RTC abstraction + * + * Copyright (C) 2008 Kyle McMartin + */ + +#include +#include +#include +#include +#include + +static int __init generic_rtc_probe(struct platform_device *dev) +{ + struct rtc_device *rtc; + const struct rtc_class_ops *ops = dev_get_platdata(&dev->dev); + + rtc = devm_rtc_device_register(&dev->dev, "rtc-generic", + ops, THIS_MODULE); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + platform_set_drvdata(dev, rtc); + + return 0; +} + +static struct platform_driver generic_rtc_driver = { + .driver = { + .name = "rtc-generic", + }, +}; + +module_platform_driver_probe(generic_rtc_driver, generic_rtc_probe); + +MODULE_AUTHOR("Kyle McMartin "); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Generic RTC driver"); +MODULE_ALIAS("platform:rtc-generic"); -- cgit v1.3.1