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 --- lib/dhry_run.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 lib/dhry_run.c (limited to 'lib/dhry_run.c') diff --git a/lib/dhry_run.c b/lib/dhry_run.c new file mode 100644 index 000000000..4a6d05ce4 --- /dev/null +++ b/lib/dhry_run.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Dhrystone benchmark test module + * + * Copyright (C) 2022 Glider bv + */ + +#include "dhry.h" + +#include +#include +#include +#include + +#define DHRY_VAX 1757 + +static int dhry_run_set(const char *val, const struct kernel_param *kp); +static const struct kernel_param_ops run_ops = { + .flags = KERNEL_PARAM_OPS_FL_NOARG, + .set = dhry_run_set, +}; +static bool dhry_run; +module_param_cb(run, &run_ops, &dhry_run, 0200); +MODULE_PARM_DESC(run, "Run the test (default: false)"); + +static int iterations = -1; +module_param(iterations, int, 0644); +MODULE_PARM_DESC(iterations, + "Number of iterations through the benchmark (default: auto)"); + +static void dhry_benchmark(void) +{ + unsigned int cpu = get_cpu(); + int i, n; + + if (iterations > 0) { + n = dhry(iterations); + goto report; + } + + for (i = DHRY_VAX; i > 0; i <<= 1) { + n = dhry(i); + if (n != -EAGAIN) + break; + } + +report: + put_cpu(); + if (n >= 0) + pr_info("CPU%u: Dhrystones per Second: %d (%d DMIPS)\n", cpu, + n, n / DHRY_VAX); + else if (n == -EAGAIN) + pr_err("Please increase the number of iterations\n"); + else + pr_err("Dhrystone benchmark failed error %pe\n", ERR_PTR(n)); +} + +static int dhry_run_set(const char *val, const struct kernel_param *kp) +{ + int ret; + + if (val) { + ret = param_set_bool(val, kp); + if (ret) + return ret; + } else { + dhry_run = true; + } + + if (dhry_run && system_state == SYSTEM_RUNNING) + dhry_benchmark(); + + return 0; +} + +static int __init dhry_init(void) +{ + if (dhry_run) + dhry_benchmark(); + + return 0; +} +module_init(dhry_init); + +MODULE_AUTHOR("Geert Uytterhoeven "); +MODULE_DESCRIPTION("Dhrystone benchmark test module"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1