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 --- tools/perf/util/evswitch.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 tools/perf/util/evswitch.c (limited to 'tools/perf/util/evswitch.c') diff --git a/tools/perf/util/evswitch.c b/tools/perf/util/evswitch.c new file mode 100644 index 000000000..d4c06a3f8 --- /dev/null +++ b/tools/perf/util/evswitch.c @@ -0,0 +1,62 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (C) 2019, Red Hat Inc, Arnaldo Carvalho de Melo + +#include +#include "evswitch.h" +#include "evlist.h" + +bool evswitch__discard(struct evswitch *evswitch, struct evsel *evsel) +{ + if (evswitch->on && evswitch->discarding) { + if (evswitch->on != evsel) + return true; + + evswitch->discarding = false; + + if (!evswitch->show_on_off_events) + return true; + + return false; + } + + if (evswitch->off && !evswitch->discarding) { + if (evswitch->off != evsel) + return false; + + evswitch->discarding = true; + + if (!evswitch->show_on_off_events) + return true; + } + + return false; +} + +static int evswitch__fprintf_enoent(FILE *fp, const char *evtype, const char *evname) +{ + int printed = fprintf(fp, "ERROR: switch-%s event not found (%s)\n", evtype, evname); + + return printed += fprintf(fp, "HINT: use 'perf evlist' to see the available event names\n"); +} + +int evswitch__init(struct evswitch *evswitch, struct evlist *evlist, FILE *fp) +{ + if (evswitch->on_name) { + evswitch->on = evlist__find_evsel_by_str(evlist, evswitch->on_name); + if (evswitch->on == NULL) { + evswitch__fprintf_enoent(fp, "on", evswitch->on_name); + return -ENOENT; + } + evswitch->discarding = true; + } + + if (evswitch->off_name) { + evswitch->off = evlist__find_evsel_by_str(evlist, evswitch->off_name); + if (evswitch->off == NULL) { + evswitch__fprintf_enoent(fp, "off", evswitch->off_name); + return -ENOENT; + } + } + + return 0; +} -- cgit v1.3.1