![Takashi Iwai](/assets/img/avatar_default.png)
The OSS sequencer client tries to drain the pending events at releasing. Unfortunately, as spotted by syzkaller fuzzer, this may lead to an unkillable process state when the event has been queued at the far future. Since the process being released can't be signaled any longer, it remains and waits for the echo-back event in that far future. Back to history, the draining feature was implemented at the time we misinterpreted POSIX definition for blocking file operation. Actually, such a behavior is superfluous at release, and we should just release the device as is instead of keeping it up forever. This patch just removes the draining call that may block the release for too long time unexpectedly. BugLink: http://lkml.kernel.org/r/CACT4Y+Y4kD-aBGj37rf-xBw9bH3GMU6P+MYg4W1e-s-paVD2pg@mail.gmail.com Reported-by: Dmitry Vyukov <dvyukov@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
176 lines
4.5 KiB
C
176 lines
4.5 KiB
C
/*
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* OSS compatible sequencer driver
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*
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* Copyright (C) 1998,99 Takashi Iwai <tiwai@suse.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef __SEQ_OSS_DEVICE_H
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#define __SEQ_OSS_DEVICE_H
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#include <linux/time.h>
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#include <linux/wait.h>
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <sound/core.h>
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#include <sound/seq_oss.h>
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#include <sound/rawmidi.h>
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#include <sound/seq_kernel.h>
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#include <sound/info.h>
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/* max. applications */
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#define SNDRV_SEQ_OSS_MAX_CLIENTS 16
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#define SNDRV_SEQ_OSS_MAX_SYNTH_DEVS 16
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#define SNDRV_SEQ_OSS_MAX_MIDI_DEVS 32
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/* version */
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#define SNDRV_SEQ_OSS_MAJOR_VERSION 0
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#define SNDRV_SEQ_OSS_MINOR_VERSION 1
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#define SNDRV_SEQ_OSS_TINY_VERSION 8
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#define SNDRV_SEQ_OSS_VERSION_STR "0.1.8"
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/* device and proc interface name */
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#define SNDRV_SEQ_OSS_PROCNAME "oss"
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/*
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* type definitions
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*/
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typedef unsigned int reltime_t;
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typedef unsigned int abstime_t;
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/*
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* synthesizer channel information
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*/
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struct seq_oss_chinfo {
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int note, vel;
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};
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/*
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* synthesizer information
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*/
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struct seq_oss_synthinfo {
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struct snd_seq_oss_arg arg;
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struct seq_oss_chinfo *ch;
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struct seq_oss_synth_sysex *sysex;
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int nr_voices;
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int opened;
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int is_midi;
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int midi_mapped;
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};
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/*
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* sequencer client information
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*/
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struct seq_oss_devinfo {
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int index; /* application index */
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int cseq; /* sequencer client number */
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int port; /* sequencer port number */
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int queue; /* sequencer queue number */
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struct snd_seq_addr addr; /* address of this device */
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int seq_mode; /* sequencer mode */
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int file_mode; /* file access */
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/* midi device table */
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int max_mididev;
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/* synth device table */
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int max_synthdev;
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struct seq_oss_synthinfo synths[SNDRV_SEQ_OSS_MAX_SYNTH_DEVS];
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int synth_opened;
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/* output queue */
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struct seq_oss_writeq *writeq;
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/* midi input queue */
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struct seq_oss_readq *readq;
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/* timer */
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struct seq_oss_timer *timer;
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};
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/*
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* function prototypes
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*/
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/* create/delete OSS sequencer client */
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int snd_seq_oss_create_client(void);
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int snd_seq_oss_delete_client(void);
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/* device file interface */
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int snd_seq_oss_open(struct file *file, int level);
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void snd_seq_oss_release(struct seq_oss_devinfo *dp);
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int snd_seq_oss_ioctl(struct seq_oss_devinfo *dp, unsigned int cmd, unsigned long arg);
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int snd_seq_oss_read(struct seq_oss_devinfo *dev, char __user *buf, int count);
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int snd_seq_oss_write(struct seq_oss_devinfo *dp, const char __user *buf, int count, struct file *opt);
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unsigned int snd_seq_oss_poll(struct seq_oss_devinfo *dp, struct file *file, poll_table * wait);
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void snd_seq_oss_reset(struct seq_oss_devinfo *dp);
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/* */
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void snd_seq_oss_process_queue(struct seq_oss_devinfo *dp, abstime_t time);
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/* proc interface */
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void snd_seq_oss_system_info_read(struct snd_info_buffer *buf);
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void snd_seq_oss_midi_info_read(struct snd_info_buffer *buf);
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void snd_seq_oss_synth_info_read(struct snd_info_buffer *buf);
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void snd_seq_oss_readq_info_read(struct seq_oss_readq *q, struct snd_info_buffer *buf);
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/* file mode macros */
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#define is_read_mode(mode) ((mode) & SNDRV_SEQ_OSS_FILE_READ)
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#define is_write_mode(mode) ((mode) & SNDRV_SEQ_OSS_FILE_WRITE)
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#define is_nonblock_mode(mode) ((mode) & SNDRV_SEQ_OSS_FILE_NONBLOCK)
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/* dispatch event */
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static inline int
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snd_seq_oss_dispatch(struct seq_oss_devinfo *dp, struct snd_seq_event *ev, int atomic, int hop)
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{
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return snd_seq_kernel_client_dispatch(dp->cseq, ev, atomic, hop);
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}
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/* ioctl */
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static inline int
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snd_seq_oss_control(struct seq_oss_devinfo *dp, unsigned int type, void *arg)
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{
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return snd_seq_kernel_client_ctl(dp->cseq, type, arg);
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}
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/* fill the addresses in header */
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static inline void
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snd_seq_oss_fill_addr(struct seq_oss_devinfo *dp, struct snd_seq_event *ev,
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int dest_client, int dest_port)
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{
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ev->queue = dp->queue;
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ev->source = dp->addr;
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ev->dest.client = dest_client;
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ev->dest.port = dest_port;
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}
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/* misc. functions for proc interface */
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char *enabled_str(int bool);
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#endif /* __SEQ_OSS_DEVICE_H */
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