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 --- include/sound/seq_device.h | 86 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 86 insertions(+) create mode 100644 include/sound/seq_device.h (limited to 'include/sound/seq_device.h') diff --git a/include/sound/seq_device.h b/include/sound/seq_device.h new file mode 100644 index 000000000..3137d4c5f --- /dev/null +++ b/include/sound/seq_device.h @@ -0,0 +1,86 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef __SOUND_SEQ_DEVICE_H +#define __SOUND_SEQ_DEVICE_H + +/* + * ALSA sequencer device management + * Copyright (c) 1999 by Takashi Iwai + */ + +/* + * registered device information + */ + +struct snd_seq_device { + /* device info */ + struct snd_card *card; /* sound card */ + int device; /* device number */ + const char *id; /* driver id */ + char name[80]; /* device name */ + int argsize; /* size of the argument */ + void *driver_data; /* private data for driver */ + void *private_data; /* private data for the caller */ + void (*private_free)(struct snd_seq_device *device); + struct device dev; + unsigned char args[]; /* driver-specific argument */ +}; + +#define to_seq_dev(_dev) \ + container_of(_dev, struct snd_seq_device, dev) + +/* sequencer driver */ + +/* driver operators + * probe: + * Initialize the device with given parameters. + * Typically, + * 1. call snd_hwdep_new + * 2. allocate private data and initialize it + * 3. call snd_hwdep_register + * 4. store the instance to dev->driver_data pointer. + * + * remove: + * Release the private data. + * Typically, call snd_device_free(dev->card, dev->driver_data) + */ +struct snd_seq_driver { + int (*probe)(struct snd_seq_device *dev); + void (*remove)(struct snd_seq_device *dev); + struct device_driver driver; + char *id; + int argsize; +}; + +#define to_seq_drv(_drv) \ + container_of(_drv, struct snd_seq_driver, driver) + +/* + * prototypes + */ +#ifdef CONFIG_MODULES +void snd_seq_device_load_drivers(void); +#else +#define snd_seq_device_load_drivers() +#endif +int snd_seq_device_new(struct snd_card *card, int device, const char *id, + int argsize, struct snd_seq_device **result); + +#define SNDRV_SEQ_DEVICE_ARGPTR(dev) ((void *)(dev)->args) + +int __must_check __snd_seq_driver_register(struct snd_seq_driver *drv, + struct module *mod); +#define snd_seq_driver_register(drv) \ + __snd_seq_driver_register(drv, THIS_MODULE) +void snd_seq_driver_unregister(struct snd_seq_driver *drv); + +#define module_snd_seq_driver(drv) \ + module_driver(drv, snd_seq_driver_register, snd_seq_driver_unregister) + +/* + * id strings for generic devices + */ +#define SNDRV_SEQ_DEV_ID_MIDISYNTH "seq-midi" +#define SNDRV_SEQ_DEV_ID_OPL3 "opl3-synth" +#define SNDRV_SEQ_DEV_ID_UMP "seq-ump-client" + +#endif /* __SOUND_SEQ_DEVICE_H */ -- cgit v1.3.1