The rawmidi read and write functions manage runtime stream status
such as runtime->appl_ptr and runtime->avail.  These point where to
copy the new data and how many bytes have been copied (or to be
read).  The problem is that rawmidi read/write call copy_from_user()
or copy_to_user(), and the runtime spinlock is temporarily unlocked
and relocked while copying user-space.  Since the current code
advances and updates the runtime status after the spin unlock/relock,
the copy and the update may be asynchronous, and eventually
runtime->avail might go to a negative value when many concurrent
accesses are done.  This may lead to memory corruption in the end.

For fixing this race, in this patch, the status update code is
performed in the same lock before the temporary unlock.  Also, the
spinlock is now taken more widely in snd_rawmidi_kernel_read1() for
protecting more properly during the whole operation.

BugLink: http://lkml.kernel.org/r/CACT4Y+b-dCmNf1GpgPKfDO0ih+uZCL2JV4__j-r1kdhPLSgQCQ@mail.gmail.comReported-by: NDmitry Vyukov <dvyukov@google.com>
Tested-by: NDmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

A kernel WARNING in snd_rawmidi_transmit_ack() is triggered by
syzkaller fuzzer:
  WARNING: CPU: 1 PID: 20739 at sound/core/rawmidi.c:1136
Call Trace:
 [<     inline     >] __dump_stack lib/dump_stack.c:15
 [<ffffffff82999e2d>] dump_stack+0x6f/0xa2 lib/dump_stack.c:50
 [<ffffffff81352089>] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482
 [<ffffffff813522b9>] warn_slowpath_null+0x29/0x30 kernel/panic.c:515
 [<ffffffff84f80bd5>] snd_rawmidi_transmit_ack+0x275/0x400 sound/core/rawmidi.c:1136
 [<ffffffff84fdb3c1>] snd_virmidi_output_trigger+0x4b1/0x5a0 sound/core/seq/seq_virmidi.c:163
 [<     inline     >] snd_rawmidi_output_trigger sound/core/rawmidi.c:150
 [<ffffffff84f87ed9>] snd_rawmidi_kernel_write1+0x549/0x780 sound/core/rawmidi.c:1223
 [<ffffffff84f89fd3>] snd_rawmidi_write+0x543/0xb30 sound/core/rawmidi.c:1273
 [<ffffffff817b0323>] __vfs_write+0x113/0x480 fs/read_write.c:528
 [<ffffffff817b1db7>] vfs_write+0x167/0x4a0 fs/read_write.c:577
 [<     inline     >] SYSC_write fs/read_write.c:624
 [<ffffffff817b50a1>] SyS_write+0x111/0x220 fs/read_write.c:616
 [<ffffffff86336c36>] entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185

Also a similar warning is found but in another path:
Call Trace:
 [<     inline     >] __dump_stack lib/dump_stack.c:15
 [<ffffffff82be2c0d>] dump_stack+0x6f/0xa2 lib/dump_stack.c:50
 [<ffffffff81355139>] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482
 [<ffffffff81355369>] warn_slowpath_null+0x29/0x30 kernel/panic.c:515
 [<ffffffff8527e69a>] rawmidi_transmit_ack+0x24a/0x3b0 sound/core/rawmidi.c:1133
 [<ffffffff8527e851>] snd_rawmidi_transmit_ack+0x51/0x80 sound/core/rawmidi.c:1163
 [<ffffffff852d9046>] snd_virmidi_output_trigger+0x2b6/0x570 sound/core/seq/seq_virmidi.c:185
 [<     inline     >] snd_rawmidi_output_trigger sound/core/rawmidi.c:150
 [<ffffffff85285a0b>] snd_rawmidi_kernel_write1+0x4bb/0x760 sound/core/rawmidi.c:1252
 [<ffffffff85287b73>] snd_rawmidi_write+0x543/0xb30 sound/core/rawmidi.c:1302
 [<ffffffff817ba5f3>] __vfs_write+0x113/0x480 fs/read_write.c:528
 [<ffffffff817bc087>] vfs_write+0x167/0x4a0 fs/read_write.c:577
 [<     inline     >] SYSC_write fs/read_write.c:624
 [<ffffffff817bf371>] SyS_write+0x111/0x220 fs/read_write.c:616
 [<ffffffff86660276>] entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185

In the former case, the reason is that virmidi has an open code
calling snd_rawmidi_transmit_ack() with the value calculated outside
the spinlock.   We may use snd_rawmidi_transmit() in a loop just for
consuming the input data, but even there, there is a race between
snd_rawmidi_transmit_peek() and snd_rawmidi_tranmit_ack().

Similarly in the latter case, it calls snd_rawmidi_transmit_peek() and
snd_rawmidi_tranmit_ack() separately without protection, so they are
racy as well.

The patch tries to address these issues by the following ways:
- Introduce the unlocked versions of snd_rawmidi_transmit_peek() and
  snd_rawmidi_transmit_ack() to be called inside the explicit lock.
- Rewrite snd_rawmidi_transmit() to be race-free (the former case).
- Make the split calls (the latter case) protected in the rawmidi spin
  lock.

BugLink: http://lkml.kernel.org/r/CACT4Y+YPq1+cYLkadwjWa5XjzF1_Vki1eHnVn-Lm0hzhSpu5PA@mail.gmail.com
BugLink: http://lkml.kernel.org/r/CACT4Y+acG4iyphdOZx47Nyq_VHGbpJQK-6xNpiqUjaZYqsXOGw@mail.gmail.comReported-by: NDmitry Vyukov <dvyukov@google.com>
Tested-by: NDmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

NULL user-space buffer can be passed even in a normal path, thus it's
not good to spew a kernel warning with stack trace at each time.
Just drop snd_BUG_ON() macro usage there.

BugLink: http://lkml.kernel.org/r/CACT4Y+YfVJ3L+q0i-4vyQVyyPD7V=OMX0PWPi29x9Bo3QaBLdw@mail.gmail.comReported-by: NDmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The kernel memory allocators already report the errors when the
requested allocation fails, thus we don't need to warn it again in
each caller side.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Now that all callers have been replaced with
snd_device_register_for_dev(), let's drop the obsolete device
registration code and concentrate only on the code handling struct
device directly.  That said,

- remove the old snd_device_register(),
- rename snd_device_register_for_dev() with snd_device_register(),
- drop superfluous arguments from snd_device_register(),
- change snd_unregister_device() to pass the device pointer directly
Reviewed-by: NJaroslav Kysela <perex@perex.cz>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

... instead of card's device.  This will be helpful to distinguish
errors from multiple rawmidi devices on a single card.
Reviewed-by: NJaroslav Kysela <perex@perex.cz>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Like previous patches, this changes the device management for rawmidi,
embedding the struct device into struct snd_rawmidi.  The required
change is more or less same as hwdep device.

The currently unused dev field is reused as the new embedded struct
field now.
Reviewed-by: NJaroslav Kysela <perex@perex.cz>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Instead of open-coding the search over the control file loop, provide
a helper function for the preferred subdevice assigned to the current
process.
Reviewed-by: NJaroslav Kysela <perex@perex.cz>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Just a cleanup to follow the standard coding style.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Use dev_err() & co as much as possible.  If not available (no device
assigned at the calling point), use pr_xxx() helpers instead.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The last argument, name, of snd_oss_register_device() is nowhere
referred in the function in the current code.  Let's drop it.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

This patch fixed 2 typos in DocBook/alsa-driver-api.xml.
It is because this file is generated by make xmldocs,
I have to fix typos within source files.
Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

script/kernel-doc reports the following type of warnings (when run in verbose
mode):

Warning(sound/core/init.c:152): No description found for return value of
'snd_card_create'

To fix that:
- add missing descriptions of function return values
- use "Return:" sections to describe those return values

Along the way:
- complete some descriptions
- fix some typos
Signed-off-by: NYacine Belkadi <yacine.belkadi.1@gmail.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

When disconnect callback is called, each component should wake up
sleepers and check card->shutdown flag for avoiding the endless sleep
blocking the proper resource release.

Cc: <stable@vger.kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

For more strict protection for wild disconnections, a refcount is
introduced to the card instance, and let it up/down when an object is
referred via snd_lookup_*() in the open ops.

The free-after-last-close check is also changed to check this refcount
instead of the empty list, too.
Reported-by: NMatthieu CASTET <matthieu.castet@parrot.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The implicit presence of module.h lured several users into
incorrectly thinking that they only needed/used modparam.h
but once we clean up the module.h presence, these will show
up as build failures, so fix 'em now.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Kill tasklet usage in rawmidi core code.  Use workq for the event callback
instead of tasklet (which is used only in core/seq/seq_midi.c).
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

When a driver module is unloaded and the last still open file is a raw
MIDI device, the card and its devices will be actually freed in the
snd_card_file_remove() call when that file is closed.  Afterwards, rmidi
and rmidi->card point into freed memory, so the module pointer is likely
to be garbage.
(This was introduced by commit 9a1b64ca.)
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Reported-by: NKrzysztof Foltman <wdev@foltman.com>
Cc: 2.6.30-2.6.35 <stable@kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

If we pass in a device which is higher than SNDRV_RAWMIDI_DEVICES then
the "next device" should be -1.  This function just returns device + 1.

But the main thing is that "device + 1" can lead to a (harmless) integer
overflow and that annoys static analysis tools.

[fix the case for device == SNDRV_RAWMIDI_DEVICE by tiwai]
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Set no_llseek to llseek file ops of each sound component (but for hwdep).
This avoids the implicit BKL invocation via generic_file_llseek() used
as default when fops.llseek is NULL.

Also call nonseekable_open() at each open ops to ensure the file flags
have no seek bit.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

While Linux provided an O_SYNC flag basically since day 1, it took until
Linux 2.4.0-test12pre2 to actually get it implemented for filesystems,
since that day we had generic_osync_around with only minor changes and the
great "For now, when the user asks for O_SYNC, we'll actually give
O_DSYNC" comment.  This patch intends to actually give us real O_SYNC
semantics in addition to the O_DSYNC semantics.  After Jan's O_SYNC
patches which are required before this patch it's actually surprisingly
simple, we just need to figure out when to set the datasync flag to
vfs_fsync_range and when not.

This patch renames the existing O_SYNC flag to O_DSYNC while keeping it's
numerical value to keep binary compatibility, and adds a new real O_SYNC
flag.  To guarantee backwards compatiblity it is defined as expanding to
both the O_DSYNC and the new additional binary flag (__O_SYNC) to make
sure we are backwards-compatible when compiled against the new headers.

This also means that all places that don't care about the differences can
just check O_DSYNC and get the right behaviour for O_SYNC, too - only
places that actuall care need to check __O_SYNC in addition.  Drivers and
network filesystems have been updated in a fail safe way to always do the
full sync magic if O_DSYNC is set.  The few places setting O_SYNC for
lower layers are kept that way for now to stay failsafe.

We enforce that O_DSYNC is set when __O_SYNC is set early in the open path
to make sure we always get these sane options.

Note that parisc really screwed up their headers as they already define a
O_DSYNC that has always been a no-op.  We try to repair it by using it for
the new O_DSYNC and redefinining O_SYNC to send both the traditional
O_SYNC numerical value _and_ the O_DSYNC one.

Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger@sun.com>
Acked-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: NKyle McMartin <kyle@mcmartin.ca>
Acked-by: NUlrich Drepper <drepper@redhat.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJan Kara <jack@suse.cz>

Record the pid of the task that opened a RawMIDI substream.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The substream_opened field is to count the number of opened substreams,
not the number of times that any substreams have been opened.

Furthermore, all substreams being opened does not imply that the next
open would fail, due to the possibility of O_APPEND.  With this wrong
check, opening a substream multiple times would succeed only if the
device had more unopened substreams.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Commit 9a1b64ca in 2.6.30 broke the
error handling code in rawmidi_open_priv().

If only the output substream of a RawMIDI device has been opened and
if this device is then opened with O_RDWR | O_APPEND and if the
initialization of the input substream fails (either because of low
memory or because the device driver's open callback fails), then the
runtime structure of the already open output substream will be freed
and all following writes through the first handle will cause
snd_rawmidi_write() to use the NULL runtime pointer.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Cc: <stable@kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Commit 9a1b64ca in 2.6.30 dropped the
check that a substream must already have been opened with O_APPEND to be
able to open it a second time.

This would make it possible for a substream to be switched to append
mode, which would mean that non-atomic writes would fail unexpectedly.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Cc: <stable@kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Commit 9a1b64ca in 2.6.30 moved the
substream initialization code to where it would be executed every time
the substream is opened.

This had the consequence that any further opening would drop and leak
the data in the existing buffer, and that the device driver's open
callback would be called multiple times, unexpectedly.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Cc: <stable@kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Instead of storing the PID number, take a reference to the task's pid
structure.  This protects against duplicates due to PID overflows, and
using pid_vnr() ensures that the PID returned by snd_ctl_elem_info() is
correct as seen from the current namespace.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Sending an Active Sensing message when closing a port can interfere with
the following data if the port is reopened and a note-on is sent before
the device's timeout has elapsed.  Therefore, it is better to disable
this setting by default.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Refactor rawmidi open/close code messes.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The module refcount should be handled in the register_mutex to avoid
possible races with module unloading.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Replace all tasklet_hi_schedule() callers with the normal
tasklet_schedule().  The former often causes troubles with
RT-kernels, and has actually no merit.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The drivers (e.g. mtpav) may call rawmidi functions in irq handlers
even though the streams are not opened.  This results in Oops or panic.

This patch adds the rawmidi state check before actually operating the
rawmidi buffers.
Tested-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The PCM and rawmidi open callbacks have a lock against card->controls_list
but it takes a wrong one, card->controls_rwsem, instead of a right one
card->ctl_files_rwlock.  This patch fixes them.

This change also fixes automatically the potential deadlocks due to
mm->mmap_sem in munmap and copy_from/to_user, reported by Sitsofe
Wheeler:

  A: snd_ctl_elem_user_tlv(): card->controls_rwsem => mm->mmap_sem
  B: snd_pcm_open(): card->open_mutex => card->controls_rwsem
  C: munmap: mm->mmap_sem => snd_pcm_release(): card->open_mutex

The patch breaks the chain.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Kill snd_assert() in sound/core/*, either removed or replaced with
if () with snd_BUG_ON().
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@perex.cz>

snd_rawmidi_kernel_read1/write1 weren't annotated but used
copy_to_user/copy_from_user when one of parameters (kernel) was equal to 0
remove it and add properly annotated parameter
Signed-off-by: NMarcin Ślusarz <marcin.slusarz@gmail.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@perex.cz>

This header file exists only for some hacks to adapt alsa-driver
tree.  It's useless for building in the kernel.  Let's move a few
lines in it to sound/core.h and remove it.
With this patch, sound/driver.h isn't removed but has just a single
compile warning to include it.  This should be really killed in
future.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@perex.cz>

Signed-off-by: NJaroslav Kysela <perex@perex.cz>

This patch cleans up duplicate includes in
	sound/core/
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NJaroslav Kysela <perex@suse.cz>

Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.

Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>