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 --- samples/rpmsg/Makefile | 2 + samples/rpmsg/rpmsg_client_sample.c | 96 +++++++++++++++++++++++++++++++++++++ 2 files changed, 98 insertions(+) create mode 100644 samples/rpmsg/Makefile create mode 100644 samples/rpmsg/rpmsg_client_sample.c (limited to 'samples/rpmsg') diff --git a/samples/rpmsg/Makefile b/samples/rpmsg/Makefile new file mode 100644 index 000000000..ddf9a5d13 --- /dev/null +++ b/samples/rpmsg/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_SAMPLE_RPMSG_CLIENT) += rpmsg_client_sample.o diff --git a/samples/rpmsg/rpmsg_client_sample.c b/samples/rpmsg/rpmsg_client_sample.c new file mode 100644 index 000000000..ae5081662 --- /dev/null +++ b/samples/rpmsg/rpmsg_client_sample.c @@ -0,0 +1,96 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Remote processor messaging - sample client driver + * + * Copyright (C) 2011 Texas Instruments, Inc. + * Copyright (C) 2011 Google, Inc. + * + * Ohad Ben-Cohen + * Brian Swetland + */ + +#include +#include +#include + +#define MSG "hello world!" + +static int count = 100; +module_param(count, int, 0644); + +struct instance_data { + int rx_count; +}; + +static int rpmsg_sample_cb(struct rpmsg_device *rpdev, void *data, int len, + void *priv, u32 src) +{ + int ret; + struct instance_data *idata = dev_get_drvdata(&rpdev->dev); + + dev_info(&rpdev->dev, "incoming msg %d (src: 0x%x)\n", + ++idata->rx_count, src); + + print_hex_dump_debug(__func__, DUMP_PREFIX_NONE, 16, 1, data, len, + true); + + /* samples should not live forever */ + if (idata->rx_count >= count) { + dev_info(&rpdev->dev, "goodbye!\n"); + return 0; + } + + /* send a new message now */ + ret = rpmsg_send(rpdev->ept, MSG, strlen(MSG)); + if (ret) + dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", ret); + + return 0; +} + +static int rpmsg_sample_probe(struct rpmsg_device *rpdev) +{ + int ret; + struct instance_data *idata; + + dev_info(&rpdev->dev, "new channel: 0x%x -> 0x%x!\n", + rpdev->src, rpdev->dst); + + idata = devm_kzalloc(&rpdev->dev, sizeof(*idata), GFP_KERNEL); + if (!idata) + return -ENOMEM; + + dev_set_drvdata(&rpdev->dev, idata); + + /* send a message to our remote processor */ + ret = rpmsg_send(rpdev->ept, MSG, strlen(MSG)); + if (ret) { + dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", ret); + return ret; + } + + return 0; +} + +static void rpmsg_sample_remove(struct rpmsg_device *rpdev) +{ + dev_info(&rpdev->dev, "rpmsg sample client driver is removed\n"); +} + +static struct rpmsg_device_id rpmsg_driver_sample_id_table[] = { + { .name = "rpmsg-client-sample" }, + { }, +}; +MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_sample_id_table); + +static struct rpmsg_driver rpmsg_sample_client = { + .drv.name = KBUILD_MODNAME, + .id_table = rpmsg_driver_sample_id_table, + .probe = rpmsg_sample_probe, + .callback = rpmsg_sample_cb, + .remove = rpmsg_sample_remove, +}; +module_rpmsg_driver(rpmsg_sample_client); + +MODULE_DESCRIPTION("Remote processor messaging sample client driver"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1