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/dio/dio-sysfs.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) create mode 100644 drivers/dio/dio-sysfs.c (limited to 'drivers/dio/dio-sysfs.c') diff --git a/drivers/dio/dio-sysfs.c b/drivers/dio/dio-sysfs.c new file mode 100644 index 000000000..ee1a3b59b --- /dev/null +++ b/drivers/dio/dio-sysfs.c @@ -0,0 +1,82 @@ +/* + * File Attributes for DIO Devices + * + * Copyright (C) 2004 Jochen Friedrich + * + * Loosely based on drivers/pci/pci-sysfs.c and drivers/zorro/zorro-sysfs.c + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of this archive + * for more details. + */ + + +#include +#include +#include + +/* show configuration fields */ + +static ssize_t dio_show_id(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct dio_dev *d; + + d = to_dio_dev(dev); + return sprintf(buf, "0x%02x\n", (d->id & 0xff)); +} +static DEVICE_ATTR(id, S_IRUGO, dio_show_id, NULL); + +static ssize_t dio_show_ipl(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct dio_dev *d; + + d = to_dio_dev(dev); + return sprintf(buf, "0x%02x\n", d->ipl); +} +static DEVICE_ATTR(ipl, S_IRUGO, dio_show_ipl, NULL); + +static ssize_t dio_show_secid(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct dio_dev *d; + + d = to_dio_dev(dev); + return sprintf(buf, "0x%02x\n", ((d->id >> 8)& 0xff)); +} +static DEVICE_ATTR(secid, S_IRUGO, dio_show_secid, NULL); + +static ssize_t dio_show_name(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct dio_dev *d; + + d = to_dio_dev(dev); + return sprintf(buf, "%s\n", d->name); +} +static DEVICE_ATTR(name, S_IRUGO, dio_show_name, NULL); + +static ssize_t dio_show_resource(struct device *dev, struct device_attribute *attr, char *buf) +{ + struct dio_dev *d = to_dio_dev(dev); + + return sprintf(buf, "0x%08lx 0x%08lx 0x%08lx\n", + (unsigned long)dio_resource_start(d), + (unsigned long)dio_resource_end(d), + dio_resource_flags(d)); +} +static DEVICE_ATTR(resource, S_IRUGO, dio_show_resource, NULL); + +int dio_create_sysfs_dev_files(struct dio_dev *d) +{ + struct device *dev = &d->dev; + int error; + + /* current configuration's attributes */ + if ((error = device_create_file(dev, &dev_attr_id)) || + (error = device_create_file(dev, &dev_attr_ipl)) || + (error = device_create_file(dev, &dev_attr_secid)) || + (error = device_create_file(dev, &dev_attr_name)) || + (error = device_create_file(dev, &dev_attr_resource))) + return error; + + return 0; +} + -- cgit v1.3.1