linux_dsm_epyc7002/sound/hda/hdac_bus.c
Takashi Iwai eb8d0eaaf8 ALSA: hda: Fix potential race at unregistration and unsol events
When the codec device is unregistered / freed, it may release the
resource while being used in an unsolicited event like the jack
detection work.  This leads to use-after-free.

The fix here is to unregister the device at first, i.e. removing the
codec from the list, then flushing the pending works to assure that
all unsol events are gone.  After this point, we're free from
accessing the codec via unsol events, thus can release the resources
gracefully.

The issue was spotted originally by Intel CI, but it couldn't be
reproduced reliably by its nature.  So let's hope this fix really
addresses the whole issues.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=196045
Reported-by: Martin Peres <martin.peres@free.fr>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2017-06-20 07:53:57 +02:00

218 lines
5.5 KiB
C

/*
* HD-audio core bus driver
*/
#include <linux/init.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/export.h>
#include <sound/hdaudio.h>
#include "trace.h"
static void process_unsol_events(struct work_struct *work);
static const struct hdac_bus_ops default_ops = {
.command = snd_hdac_bus_send_cmd,
.get_response = snd_hdac_bus_get_response,
};
/**
* snd_hdac_bus_init - initialize a HD-audio bas bus
* @bus: the pointer to bus object
* @ops: bus verb operators
* @io_ops: lowlevel I/O operators
*
* Returns 0 if successful, or a negative error code.
*/
int snd_hdac_bus_init(struct hdac_bus *bus, struct device *dev,
const struct hdac_bus_ops *ops,
const struct hdac_io_ops *io_ops)
{
memset(bus, 0, sizeof(*bus));
bus->dev = dev;
if (ops)
bus->ops = ops;
else
bus->ops = &default_ops;
bus->io_ops = io_ops;
INIT_LIST_HEAD(&bus->stream_list);
INIT_LIST_HEAD(&bus->codec_list);
INIT_WORK(&bus->unsol_work, process_unsol_events);
spin_lock_init(&bus->reg_lock);
mutex_init(&bus->cmd_mutex);
bus->irq = -1;
return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_init);
/**
* snd_hdac_bus_exit - clean up a HD-audio bas bus
* @bus: the pointer to bus object
*/
void snd_hdac_bus_exit(struct hdac_bus *bus)
{
WARN_ON(!list_empty(&bus->stream_list));
WARN_ON(!list_empty(&bus->codec_list));
cancel_work_sync(&bus->unsol_work);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_exit);
/**
* snd_hdac_bus_exec_verb - execute a HD-audio verb on the given bus
* @bus: bus object
* @cmd: HD-audio encoded verb
* @res: pointer to store the response, NULL if performing asynchronously
*
* Returns 0 if successful, or a negative error code.
*/
int snd_hdac_bus_exec_verb(struct hdac_bus *bus, unsigned int addr,
unsigned int cmd, unsigned int *res)
{
int err;
mutex_lock(&bus->cmd_mutex);
err = snd_hdac_bus_exec_verb_unlocked(bus, addr, cmd, res);
mutex_unlock(&bus->cmd_mutex);
return err;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_exec_verb);
/**
* snd_hdac_bus_exec_verb_unlocked - unlocked version
* @bus: bus object
* @cmd: HD-audio encoded verb
* @res: pointer to store the response, NULL if performing asynchronously
*
* Returns 0 if successful, or a negative error code.
*/
int snd_hdac_bus_exec_verb_unlocked(struct hdac_bus *bus, unsigned int addr,
unsigned int cmd, unsigned int *res)
{
unsigned int tmp;
int err;
if (cmd == ~0)
return -EINVAL;
if (res)
*res = -1;
else if (bus->sync_write)
res = &tmp;
for (;;) {
trace_hda_send_cmd(bus, cmd);
err = bus->ops->command(bus, cmd);
if (err != -EAGAIN)
break;
/* process pending verbs */
err = bus->ops->get_response(bus, addr, &tmp);
if (err)
break;
}
if (!err && res) {
err = bus->ops->get_response(bus, addr, res);
trace_hda_get_response(bus, addr, *res);
}
return err;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_exec_verb_unlocked);
/**
* snd_hdac_bus_queue_event - add an unsolicited event to queue
* @bus: the BUS
* @res: unsolicited event (lower 32bit of RIRB entry)
* @res_ex: codec addr and flags (upper 32bit or RIRB entry)
*
* Adds the given event to the queue. The events are processed in
* the workqueue asynchronously. Call this function in the interrupt
* hanlder when RIRB receives an unsolicited event.
*/
void snd_hdac_bus_queue_event(struct hdac_bus *bus, u32 res, u32 res_ex)
{
unsigned int wp;
if (!bus)
return;
trace_hda_unsol_event(bus, res, res_ex);
wp = (bus->unsol_wp + 1) % HDA_UNSOL_QUEUE_SIZE;
bus->unsol_wp = wp;
wp <<= 1;
bus->unsol_queue[wp] = res;
bus->unsol_queue[wp + 1] = res_ex;
schedule_work(&bus->unsol_work);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_queue_event);
/*
* process queued unsolicited events
*/
static void process_unsol_events(struct work_struct *work)
{
struct hdac_bus *bus = container_of(work, struct hdac_bus, unsol_work);
struct hdac_device *codec;
struct hdac_driver *drv;
unsigned int rp, caddr, res;
while (bus->unsol_rp != bus->unsol_wp) {
rp = (bus->unsol_rp + 1) % HDA_UNSOL_QUEUE_SIZE;
bus->unsol_rp = rp;
rp <<= 1;
res = bus->unsol_queue[rp];
caddr = bus->unsol_queue[rp + 1];
if (!(caddr & (1 << 4))) /* no unsolicited event? */
continue;
codec = bus->caddr_tbl[caddr & 0x0f];
if (!codec || !codec->dev.driver)
continue;
drv = drv_to_hdac_driver(codec->dev.driver);
if (drv->unsol_event)
drv->unsol_event(codec, res);
}
}
/**
* snd_hdac_bus_add_device - Add a codec to bus
* @bus: HDA core bus
* @codec: HDA core device to add
*
* Adds the given codec to the list in the bus. The caddr_tbl array
* and codec_powered bits are updated, as well.
* Returns zero if success, or a negative error code.
*/
int snd_hdac_bus_add_device(struct hdac_bus *bus, struct hdac_device *codec)
{
if (bus->caddr_tbl[codec->addr]) {
dev_err(bus->dev, "address 0x%x is already occupied\n",
codec->addr);
return -EBUSY;
}
list_add_tail(&codec->list, &bus->codec_list);
bus->caddr_tbl[codec->addr] = codec;
set_bit(codec->addr, &bus->codec_powered);
bus->num_codecs++;
return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_add_device);
/**
* snd_hdac_bus_remove_device - Remove a codec from bus
* @bus: HDA core bus
* @codec: HDA core device to remove
*/
void snd_hdac_bus_remove_device(struct hdac_bus *bus,
struct hdac_device *codec)
{
WARN_ON(bus != codec->bus);
if (list_empty(&codec->list))
return;
list_del_init(&codec->list);
bus->caddr_tbl[codec->addr] = NULL;
clear_bit(codec->addr, &bus->codec_powered);
bus->num_codecs--;
flush_work(&bus->unsol_work);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_remove_device);