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/input/misc/pcspkr.c | 134 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 134 insertions(+) create mode 100644 drivers/input/misc/pcspkr.c (limited to 'drivers/input/misc/pcspkr.c') diff --git a/drivers/input/misc/pcspkr.c b/drivers/input/misc/pcspkr.c new file mode 100644 index 000000000..046780840 --- /dev/null +++ b/drivers/input/misc/pcspkr.c @@ -0,0 +1,134 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * PC Speaker beeper driver for Linux + * + * Copyright (c) 2002 Vojtech Pavlik + * Copyright (c) 1992 Orest Zborowski + */ + + +#include +#include +#include +#include +#include +#include +#include + +MODULE_AUTHOR("Vojtech Pavlik "); +MODULE_DESCRIPTION("PC Speaker beeper driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:pcspkr"); + +static int pcspkr_event(struct input_dev *dev, unsigned int type, + unsigned int code, int value) +{ + unsigned int count = 0; + unsigned long flags; + + if (type != EV_SND) + return -EINVAL; + + switch (code) { + case SND_BELL: + if (value) + value = 1000; + break; + case SND_TONE: + break; + default: + return -EINVAL; + } + + if (value > 20 && value < 32767) + count = PIT_TICK_RATE / value; + + raw_spin_lock_irqsave(&i8253_lock, flags); + + if (count) { + /* set command for counter 2, 2 byte write */ + outb_p(0xB6, 0x43); + /* select desired HZ */ + outb_p(count & 0xff, 0x42); + outb((count >> 8) & 0xff, 0x42); + /* enable counter 2 */ + outb_p(inb_p(0x61) | 3, 0x61); + } else { + /* disable counter 2 */ + outb(inb_p(0x61) & 0xFC, 0x61); + } + + raw_spin_unlock_irqrestore(&i8253_lock, flags); + + return 0; +} + +static int pcspkr_probe(struct platform_device *dev) +{ + struct input_dev *pcspkr_dev; + int err; + + pcspkr_dev = input_allocate_device(); + if (!pcspkr_dev) + return -ENOMEM; + + pcspkr_dev->name = "PC Speaker"; + pcspkr_dev->phys = "isa0061/input0"; + pcspkr_dev->id.bustype = BUS_ISA; + pcspkr_dev->id.vendor = 0x001f; + pcspkr_dev->id.product = 0x0001; + pcspkr_dev->id.version = 0x0100; + pcspkr_dev->dev.parent = &dev->dev; + + pcspkr_dev->evbit[0] = BIT_MASK(EV_SND); + pcspkr_dev->sndbit[0] = BIT_MASK(SND_BELL) | BIT_MASK(SND_TONE); + pcspkr_dev->event = pcspkr_event; + + err = input_register_device(pcspkr_dev); + if (err) { + input_free_device(pcspkr_dev); + return err; + } + + platform_set_drvdata(dev, pcspkr_dev); + + return 0; +} + +static void pcspkr_remove(struct platform_device *dev) +{ + struct input_dev *pcspkr_dev = platform_get_drvdata(dev); + + input_unregister_device(pcspkr_dev); + /* turn off the speaker */ + pcspkr_event(NULL, EV_SND, SND_BELL, 0); +} + +static int pcspkr_suspend(struct device *dev) +{ + pcspkr_event(NULL, EV_SND, SND_BELL, 0); + + return 0; +} + +static void pcspkr_shutdown(struct platform_device *dev) +{ + /* turn off the speaker */ + pcspkr_event(NULL, EV_SND, SND_BELL, 0); +} + +static const struct dev_pm_ops pcspkr_pm_ops = { + .suspend = pcspkr_suspend, +}; + +static struct platform_driver pcspkr_platform_driver = { + .driver = { + .name = "pcspkr", + .pm = &pcspkr_pm_ops, + }, + .probe = pcspkr_probe, + .remove = pcspkr_remove, + .shutdown = pcspkr_shutdown, +}; +module_platform_driver(pcspkr_platform_driver); + -- cgit v1.3.1