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-starfire.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) create mode 100644 drivers/rtc/rtc-starfire.c (limited to 'drivers/rtc/rtc-starfire.c') diff --git a/drivers/rtc/rtc-starfire.c b/drivers/rtc/rtc-starfire.c new file mode 100644 index 000000000..fbd1ed41c --- /dev/null +++ b/drivers/rtc/rtc-starfire.c @@ -0,0 +1,60 @@ +/* rtc-starfire.c: Starfire platform RTC driver. + * + * Author: David S. Miller + * License: GPL + * + * Copyright (C) 2008 David S. Miller + */ + +#include +#include +#include +#include + +#include + +static u32 starfire_get_time(void) +{ + static char obp_gettod[32]; + static u32 unix_tod; + + sprintf(obp_gettod, "h# %08x unix-gettod", + (unsigned int) (long) &unix_tod); + prom_feval(obp_gettod); + + return unix_tod; +} + +static int starfire_read_time(struct device *dev, struct rtc_time *tm) +{ + rtc_time64_to_tm(starfire_get_time(), tm); + return 0; +} + +static const struct rtc_class_ops starfire_rtc_ops = { + .read_time = starfire_read_time, +}; + +static int __init starfire_rtc_probe(struct platform_device *pdev) +{ + struct rtc_device *rtc; + + rtc = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(rtc)) + return PTR_ERR(rtc); + + rtc->ops = &starfire_rtc_ops; + rtc->range_max = U32_MAX; + + platform_set_drvdata(pdev, rtc); + + return devm_rtc_register_device(rtc); +} + +static struct platform_driver starfire_rtc_driver = { + .driver = { + .name = "rtc-starfire", + }, +}; + +builtin_platform_driver_probe(starfire_rtc_driver, starfire_rtc_probe); -- cgit v1.3.1