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/pps/sysfs.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) create mode 100644 drivers/pps/sysfs.c (limited to 'drivers/pps/sysfs.c') diff --git a/drivers/pps/sysfs.c b/drivers/pps/sysfs.c new file mode 100644 index 000000000..134bc33f6 --- /dev/null +++ b/drivers/pps/sysfs.c @@ -0,0 +1,99 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * PPS sysfs support + * + * Copyright (C) 2007-2009 Rodolfo Giometti + */ + + +#include +#include +#include +#include + +/* + * Attribute functions + */ + +static ssize_t assert_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_device *pps = dev_get_drvdata(dev); + + if (!(pps->info.mode & PPS_CAPTUREASSERT)) + return 0; + + return sprintf(buf, "%lld.%09d#%d\n", + (long long) pps->assert_tu.sec, pps->assert_tu.nsec, + pps->assert_sequence); +} +static DEVICE_ATTR_RO(assert); + +static ssize_t clear_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_device *pps = dev_get_drvdata(dev); + + if (!(pps->info.mode & PPS_CAPTURECLEAR)) + return 0; + + return sprintf(buf, "%lld.%09d#%d\n", + (long long) pps->clear_tu.sec, pps->clear_tu.nsec, + pps->clear_sequence); +} +static DEVICE_ATTR_RO(clear); + +static ssize_t mode_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_device *pps = dev_get_drvdata(dev); + + return sprintf(buf, "%4x\n", pps->info.mode); +} +static DEVICE_ATTR_RO(mode); + +static ssize_t echo_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_device *pps = dev_get_drvdata(dev); + + return sprintf(buf, "%d\n", !!pps->info.echo); +} +static DEVICE_ATTR_RO(echo); + +static ssize_t name_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_device *pps = dev_get_drvdata(dev); + + return sprintf(buf, "%s\n", pps->info.name); +} +static DEVICE_ATTR_RO(name); + +static ssize_t path_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_device *pps = dev_get_drvdata(dev); + + return sprintf(buf, "%s\n", pps->info.path); +} +static DEVICE_ATTR_RO(path); + +static struct attribute *pps_attrs[] = { + &dev_attr_assert.attr, + &dev_attr_clear.attr, + &dev_attr_mode.attr, + &dev_attr_echo.attr, + &dev_attr_name.attr, + &dev_attr_path.attr, + NULL, +}; + +static const struct attribute_group pps_group = { + .attrs = pps_attrs, +}; + +const struct attribute_group *pps_groups[] = { + &pps_group, + NULL, +}; -- cgit v1.3.1