Currently the ALSA proc handler allows read or write even if the proc
file were write-only or read-only.  It's mostly harmless, does thing
but allocating memory and ignores the input/output.  But it doesn't
tell user about the invalid use, and it's confusing and inconsistent
in comparison with other proc files.

This patch adds some sanity checks and let the proc handler returning
an -EIO error when the invalid read/write is performed.

Cc: <stable@vger.kernel.org> # v4.2+
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The ALSA proc handler allows currently the write in the unlimited size
until kmalloc() fails.  But basically the write is supposed to be only
for small inputs, mostly for one line inputs, and we don't have to
handle too large sizes at all.  Since the kmalloc error results in the
kernel warning, it's better to limit the size beforehand.

This patch adds the limit of 16kB, which must be large enough for the
currently existing code.

Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The recent rewrite of the sequencer time accounting using timespec64
in the commit [3915bf29: ALSA: seq_timer: use monotonic times
internally] introduced a bad regression.  Namely, the time reported
back doesn't increase but goes back and forth.

The culprit was obvious: the delta is stored to the result (cur_time =
delta), instead of adding the delta (cur_time += delta)!

Let's fix it.

Fixes: 3915bf29 ('ALSA: seq_timer: use monotonic times internally')
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=177571Reported-by: NYves Guillemot <yc.guillemot@wanadoo.fr>
Cc: <stable@vger.kernel.org> # v4.8+
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

This commit is a fix for Linux 4.9-rc1.

In former commit, a function call of compatibility layer for ALSA sequencer
core was obsoleted by an alternative. Although, the alternative gets a
pointer to kernel stack due to mis-programming. As a result, ALSA sequencer
core unexpectedly refers over kernel stack.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Fixes: 8ce8eb60 ("ALSA: seq: add an alternative way to handle ioctl requests")
Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Fix a missing \n in a pr_debug message and move the \n to the end
of a pr_err message.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

When checking value of request for copy operation, current implementation
compares shifted value to macros, while these macros are already shifted.
As a result, it never performs to copy from/to user space.

This commit fixes the bug.

Fixes: 8ce8eb60('ALSA: seq: add an alternative way to handle ioctl requests'
Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

When a seq-virmidi driver is initialized, it registers a rawmidi
instance with its callback to create an associated seq kernel client.
Currently it's done throughly in rawmidi's register_mutex context.
Recently it was found that this may lead to a deadlock another rawmidi
device that is being attached with the sequencer is accessed, as both
open with the same register_mutex.  This was actually triggered by
syzkaller, as Dmitry Vyukov reported:

======================================================
 [ INFO: possible circular locking dependency detected ]
 4.8.0-rc1+ #11 Not tainted
 -------------------------------------------------------
 syz-executor/7154 is trying to acquire lock:
  (register_mutex#5){+.+.+.}, at: [<ffffffff84fd6d4b>] snd_rawmidi_kernel_open+0x4b/0x260 sound/core/rawmidi.c:341

 but task is already holding lock:
  (&grp->list_mutex){++++.+}, at: [<ffffffff850138bb>] check_and_subscribe_port+0x5b/0x5c0 sound/core/seq/seq_ports.c:495

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #1 (&grp->list_mutex){++++.+}:
    [<ffffffff8147a3a8>] lock_acquire+0x208/0x430 kernel/locking/lockdep.c:3746
    [<ffffffff863f6199>] down_read+0x49/0xc0 kernel/locking/rwsem.c:22
    [<     inline     >] deliver_to_subscribers sound/core/seq/seq_clientmgr.c:681
    [<ffffffff85005c5e>] snd_seq_deliver_event+0x35e/0x890 sound/core/seq/seq_clientmgr.c:822
    [<ffffffff85006e96>] > snd_seq_kernel_client_dispatch+0x126/0x170 sound/core/seq/seq_clientmgr.c:2418
    [<ffffffff85012c52>] snd_seq_system_broadcast+0xb2/0xf0 sound/core/seq/seq_system.c:101
    [<ffffffff84fff70a>] snd_seq_create_kernel_client+0x24a/0x330 sound/core/seq/seq_clientmgr.c:2297
    [<     inline     >] snd_virmidi_dev_attach_seq sound/core/seq/seq_virmidi.c:383
    [<ffffffff8502d29f>] snd_virmidi_dev_register+0x29f/0x750 sound/core/seq/seq_virmidi.c:450
    [<ffffffff84fd208c>] snd_rawmidi_dev_register+0x30c/0xd40 sound/core/rawmidi.c:1645
    [<ffffffff84f816d3>] __snd_device_register.part.0+0x63/0xc0 sound/core/device.c:164
    [<     inline     >] __snd_device_register sound/core/device.c:162
    [<ffffffff84f8235d>] snd_device_register_all+0xad/0x110 sound/core/device.c:212
    [<ffffffff84f7546f>] snd_card_register+0xef/0x6c0 sound/core/init.c:749
    [<ffffffff85040b7f>] snd_virmidi_probe+0x3ef/0x590 sound/drivers/virmidi.c:123
    [<ffffffff833ebf7b>] platform_drv_probe+0x8b/0x170 drivers/base/platform.c:564
    ......

 -> #0 (register_mutex#5){+.+.+.}:
    [<     inline     >] check_prev_add kernel/locking/lockdep.c:1829
    [<     inline     >] check_prevs_add kernel/locking/lockdep.c:1939
    [<     inline     >] validate_chain kernel/locking/lockdep.c:2266
    [<ffffffff814791f4>] __lock_acquire+0x4d44/0x4d80 kernel/locking/lockdep.c:3335
    [<ffffffff8147a3a8>] lock_acquire+0x208/0x430 kernel/locking/lockdep.c:3746
    [<     inline     >] __mutex_lock_common kernel/locking/mutex.c:521
    [<ffffffff863f0ef1>] mutex_lock_nested+0xb1/0xa20 kernel/locking/mutex.c:621
    [<ffffffff84fd6d4b>] snd_rawmidi_kernel_open+0x4b/0x260 sound/core/rawmidi.c:341
    [<ffffffff8502e7c7>] midisynth_subscribe+0xf7/0x350 sound/core/seq/seq_midi.c:188
    [<     inline     >] subscribe_port sound/core/seq/seq_ports.c:427
    [<ffffffff85013cc7>] check_and_subscribe_port+0x467/0x5c0 sound/core/seq/seq_ports.c:510
    [<ffffffff85015da9>] snd_seq_port_connect+0x2c9/0x500 sound/core/seq/seq_ports.c:579
    [<ffffffff850079b8>] snd_seq_ioctl_subscribe_port+0x1d8/0x2b0 sound/core/seq/seq_clientmgr.c:1480
    [<ffffffff84ffe9e4>] snd_seq_do_ioctl+0x184/0x1e0 sound/core/seq/seq_clientmgr.c:2225
    [<ffffffff84ffeae8>] snd_seq_kernel_client_ctl+0xa8/0x110 sound/core/seq/seq_clientmgr.c:2440
    [<ffffffff85027664>] snd_seq_oss_midi_open+0x3b4/0x610 sound/core/seq/oss/seq_oss_midi.c:375
    [<ffffffff85023d67>] snd_seq_oss_synth_setup_midi+0x107/0x4c0 sound/core/seq/oss/seq_oss_synth.c:281
    [<ffffffff8501b0a8>] snd_seq_oss_open+0x748/0x8d0 sound/core/seq/oss/seq_oss_init.c:274
    [<ffffffff85019d8a>] odev_open+0x6a/0x90 sound/core/seq/oss/seq_oss.c:138
    [<ffffffff84f7040f>] soundcore_open+0x30f/0x640 sound/sound_core.c:639
    ......

 other info that might help us debug this:

 Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&grp->list_mutex);
                                lock(register_mutex#5);
                                lock(&grp->list_mutex);
   lock(register_mutex#5);

 *** DEADLOCK ***
======================================================

The fix is to simply move the registration parts in
snd_rawmidi_dev_register() to the outside of the register_mutex lock.
The lock is needed only to manage the linked list, and it's not
necessarily to cover the whole initialization process.
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

When a user timer instance is continued without the explicit start
beforehand, the system gets eventually zero-division error like:

  divide error: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN
  CPU: 1 PID: 27320 Comm: syz-executor Not tainted 4.8.0-rc3-next-20160825+ #8
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
   task: ffff88003c9b2280 task.stack: ffff880027280000
   RIP: 0010:[<ffffffff858e1a6c>]  [<     inline     >] ktime_divns include/linux/ktime.h:195
   RIP: 0010:[<ffffffff858e1a6c>]  [<ffffffff858e1a6c>] snd_hrtimer_callback+0x1bc/0x3c0 sound/core/hrtimer.c:62
  Call Trace:
   <IRQ>
   [<     inline     >] __run_hrtimer kernel/time/hrtimer.c:1238
   [<ffffffff81504335>] __hrtimer_run_queues+0x325/0xe70 kernel/time/hrtimer.c:1302
   [<ffffffff81506ceb>] hrtimer_interrupt+0x18b/0x420 kernel/time/hrtimer.c:1336
   [<ffffffff8126d8df>] local_apic_timer_interrupt+0x6f/0xe0 arch/x86/kernel/apic/apic.c:933
   [<ffffffff86e13056>] smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:957
   [<ffffffff86e1210c>] apic_timer_interrupt+0x8c/0xa0 arch/x86/entry/entry_64.S:487
   <EOI>
   .....

Although a similar issue was spotted and a fix patch was merged in
commit [6b760bb2: ALSA: timer: fix division by zero after
SNDRV_TIMER_IOCTL_CONTINUE], it seems covering only a part of
iceberg.

In this patch, we fix the issue a bit more drastically.  Basically the
continue of an uninitialized timer is supposed to be a fresh start, so
we do it for user timers.  For the direct snd_timer_continue() call,
there is no way to pass the initial tick value, so we kick out for the
uninitialized case.
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

When the stream is in suspended state some applications wait
on "Stream Pipe Error" in response to snd_pcm_avail call to
resume the stream.

In the current implementation snd_pcm_avail() returns zero
when the stream is in suspended state. This causes application
to enter in infinite loop for frames to be available.

"Stream pipe Error" code is getting returned for read/write
call when the stream is in suspended state. Similarly update
snd_pcm_avail to return -ESTRPIPE.
Signed-off-by: NJeeja KP <jeeja.kp@intel.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

I got this with syzkaller:

    ==================================================================
    BUG: KASAN: null-ptr-deref on address 0000000000000020
    Read of size 32 by task syz-executor/22519
    CPU: 1 PID: 22519 Comm: syz-executor Not tainted 4.8.0-rc2+ #169
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2
    014
     0000000000000001 ffff880111a17a00 ffffffff81f9f141 ffff880111a17a90
     ffff880111a17c50 ffff880114584a58 ffff880114584a10 ffff880111a17a80
     ffffffff8161fe3f ffff880100000000 ffff880118d74a48 ffff880118d74a68
    Call Trace:
     [<ffffffff81f9f141>] dump_stack+0x83/0xb2
     [<ffffffff8161fe3f>] kasan_report_error+0x41f/0x4c0
     [<ffffffff8161ff74>] kasan_report+0x34/0x40
     [<ffffffff82c84b54>] ? snd_timer_user_read+0x554/0x790
     [<ffffffff8161e79e>] check_memory_region+0x13e/0x1a0
     [<ffffffff8161e9c1>] kasan_check_read+0x11/0x20
     [<ffffffff82c84b54>] snd_timer_user_read+0x554/0x790
     [<ffffffff82c84600>] ? snd_timer_user_info_compat.isra.5+0x2b0/0x2b0
     [<ffffffff817d0831>] ? proc_fault_inject_write+0x1c1/0x250
     [<ffffffff817d0670>] ? next_tgid+0x2a0/0x2a0
     [<ffffffff8127c278>] ? do_group_exit+0x108/0x330
     [<ffffffff8174653a>] ? fsnotify+0x72a/0xca0
     [<ffffffff81674dfe>] __vfs_read+0x10e/0x550
     [<ffffffff82c84600>] ? snd_timer_user_info_compat.isra.5+0x2b0/0x2b0
     [<ffffffff81674cf0>] ? do_sendfile+0xc50/0xc50
     [<ffffffff81745e10>] ? __fsnotify_update_child_dentry_flags+0x60/0x60
     [<ffffffff8143fec6>] ? kcov_ioctl+0x56/0x190
     [<ffffffff81e5ada2>] ? common_file_perm+0x2e2/0x380
     [<ffffffff81746b0e>] ? __fsnotify_parent+0x5e/0x2b0
     [<ffffffff81d93536>] ? security_file_permission+0x86/0x1e0
     [<ffffffff816728f5>] ? rw_verify_area+0xe5/0x2b0
     [<ffffffff81675355>] vfs_read+0x115/0x330
     [<ffffffff81676371>] SyS_read+0xd1/0x1a0
     [<ffffffff816762a0>] ? vfs_write+0x4b0/0x4b0
     [<ffffffff82001c2c>] ? __this_cpu_preempt_check+0x1c/0x20
     [<ffffffff8150455a>] ? __context_tracking_exit.part.4+0x3a/0x1e0
     [<ffffffff816762a0>] ? vfs_write+0x4b0/0x4b0
     [<ffffffff81005524>] do_syscall_64+0x1c4/0x4e0
     [<ffffffff810052fc>] ? syscall_return_slowpath+0x16c/0x1d0
     [<ffffffff83c3276a>] entry_SYSCALL64_slow_path+0x25/0x25
    ==================================================================

There are a couple of problems that I can see:

 - ioctl(SNDRV_TIMER_IOCTL_SELECT), which potentially sets
   tu->queue/tu->tqueue to NULL on memory allocation failure, so read()
   would get a NULL pointer dereference like the above splat

 - the same ioctl() can free tu->queue/to->tqueue which means read()
   could potentially see (and dereference) the freed pointer

We can fix both by taking the ioctl_lock mutex when dereferencing
->queue/->tqueue, since that's always held over all the ioctl() code.

Just looking at the code I find it likely that there are more problems
here such as tu->qhead pointing outside the buffer if the size is
changed concurrently using SNDRV_TIMER_IOCTL_PARAMS.
Signed-off-by: NVegard Nossum <vegard.nossum@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Currently, automatic variable of 'union ioctl_arg' type is initialized
by designated initialization. Although, the actual effect is interpretation
of early element of int type and initialization of 'int pversion'.
Therefore the first field corresponding to int type is initialized to zero.
This is against my expectation to initialize whole fields.

This commit uses memset() to initialize the variable, instead of designated
initialization.

Fixes: 04a56dd8 ('ALSA: seq: change ioctl command operation to get data in kernel space')
Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

I hit this with syzkaller:

    kasan: CONFIG_KASAN_INLINE enabled
    kasan: GPF could be caused by NULL-ptr deref or user memory access
    general protection fault: 0000 [#1] PREEMPT SMP KASAN
    CPU: 0 PID: 1327 Comm: a.out Not tainted 4.8.0-rc2+ #190
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014
    task: ffff88011278d600 task.stack: ffff8801120c0000
    RIP: 0010:[<ffffffff82c8ba07>]  [<ffffffff82c8ba07>] snd_hrtimer_start+0x77/0x100
    RSP: 0018:ffff8801120c7a60  EFLAGS: 00010006
    RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000007
    RDX: 0000000000000009 RSI: 1ffff10023483091 RDI: 0000000000000048
    RBP: ffff8801120c7a78 R08: ffff88011a5cf768 R09: ffff88011a5ba790
    R10: 0000000000000002 R11: ffffed00234b9ef1 R12: ffff880114843980
    R13: ffffffff84213c00 R14: ffff880114843ab0 R15: 0000000000000286
    FS:  00007f72958f3700(0000) GS:ffff88011aa00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 0000000000603001 CR3: 00000001126ab000 CR4: 00000000000006f0
    Stack:
     ffff880114843980 ffff880111eb2dc0 ffff880114843a34 ffff8801120c7ad0
     ffffffff82c81ab1 0000000000000000 ffffffff842138e0 0000000100000000
     ffff880111eb2dd0 ffff880111eb2dc0 0000000000000001 ffff880111eb2dc0
    Call Trace:
     [<ffffffff82c81ab1>] snd_timer_start1+0x331/0x670
     [<ffffffff82c85bfd>] snd_timer_start+0x5d/0xa0
     [<ffffffff82c8795e>] snd_timer_user_ioctl+0x88e/0x2830
     [<ffffffff8159f3a0>] ? __follow_pte.isra.49+0x430/0x430
     [<ffffffff82c870d0>] ? snd_timer_pause+0x80/0x80
     [<ffffffff815a26fa>] ? do_wp_page+0x3aa/0x1c90
     [<ffffffff8132762f>] ? put_prev_entity+0x108f/0x21a0
     [<ffffffff82c870d0>] ? snd_timer_pause+0x80/0x80
     [<ffffffff816b0733>] do_vfs_ioctl+0x193/0x1050
     [<ffffffff813510af>] ? cpuacct_account_field+0x12f/0x1a0
     [<ffffffff816b05a0>] ? ioctl_preallocate+0x200/0x200
     [<ffffffff81002f2f>] ? syscall_trace_enter+0x3cf/0xdb0
     [<ffffffff815045ba>] ? __context_tracking_exit.part.4+0x9a/0x1e0
     [<ffffffff81002b60>] ? exit_to_usermode_loop+0x190/0x190
     [<ffffffff82001a97>] ? check_preemption_disabled+0x37/0x1e0
     [<ffffffff81d93889>] ? security_file_ioctl+0x89/0xb0
     [<ffffffff816b167f>] SyS_ioctl+0x8f/0xc0
     [<ffffffff816b15f0>] ? do_vfs_ioctl+0x1050/0x1050
     [<ffffffff81005524>] do_syscall_64+0x1c4/0x4e0
     [<ffffffff83c32b2a>] entry_SYSCALL64_slow_path+0x25/0x25
    Code: c7 c7 c4 b9 c8 82 48 89 d9 4c 89 ee e8 63 88 7f fe e8 7e 46 7b fe 48 8d 7b 48 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 04 84 c0 7e 65 80 7b 48 00 74 0e e8 52 46
    RIP  [<ffffffff82c8ba07>] snd_hrtimer_start+0x77/0x100
     RSP <ffff8801120c7a60>
    ---[ end trace 5955b08db7f2b029 ]---

This can happen if snd_hrtimer_open() fails to allocate memory and
returns an error, which is currently not checked by snd_timer_open():

    ioctl(SNDRV_TIMER_IOCTL_SELECT)
     - snd_timer_user_tselect()
	- snd_timer_close()
	   - snd_hrtimer_close()
	      - (struct snd_timer *) t->private_data = NULL
        - snd_timer_open()
           - snd_hrtimer_open()
              - kzalloc() fails; t->private_data is still NULL

    ioctl(SNDRV_TIMER_IOCTL_START)
     - snd_timer_user_start()
	- snd_timer_start()
	   - snd_timer_start1()
	      - snd_hrtimer_start()
		- t->private_data == NULL // boom
Signed-off-by: NVegard Nossum <vegard.nossum@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

I got this:

    divide error: 0000 [#1] PREEMPT SMP KASAN
    CPU: 1 PID: 1327 Comm: a.out Not tainted 4.8.0-rc2+ #189
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014
    task: ffff8801120a9580 task.stack: ffff8801120b0000
    RIP: 0010:[<ffffffff82c8bd9a>]  [<ffffffff82c8bd9a>] snd_hrtimer_callback+0x1da/0x3f0
    RSP: 0018:ffff88011aa87da8  EFLAGS: 00010006
    RAX: 0000000000004f76 RBX: ffff880112655e88 RCX: 0000000000000000
    RDX: 0000000000000000 RSI: ffff880112655ea0 RDI: 0000000000000001
    RBP: ffff88011aa87e00 R08: ffff88013fff905c R09: ffff88013fff9048
    R10: ffff88013fff9050 R11: 00000001050a7b8c R12: ffff880114778a00
    R13: ffff880114778ab4 R14: ffff880114778b30 R15: 0000000000000000
    FS:  00007f071647c700(0000) GS:ffff88011aa80000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 0000000000603001 CR3: 0000000112021000 CR4: 00000000000006e0
    Stack:
     0000000000000000 ffff880114778ab8 ffff880112655ea0 0000000000004f76
     ffff880112655ec8 ffff880112655e80 ffff880112655e88 ffff88011aa98fc0
     00000000b97ccf2b dffffc0000000000 ffff88011aa98fc0 ffff88011aa87ef0
    Call Trace:
     <IRQ>
     [<ffffffff813abce7>] __hrtimer_run_queues+0x347/0xa00
     [<ffffffff82c8bbc0>] ? snd_hrtimer_close+0x130/0x130
     [<ffffffff813ab9a0>] ? retrigger_next_event+0x1b0/0x1b0
     [<ffffffff813ae1a6>] ? hrtimer_interrupt+0x136/0x4b0
     [<ffffffff813ae220>] hrtimer_interrupt+0x1b0/0x4b0
     [<ffffffff8120f91e>] local_apic_timer_interrupt+0x6e/0xf0
     [<ffffffff81227ad3>] ? kvm_guest_apic_eoi_write+0x13/0xc0
     [<ffffffff83c35086>] smp_apic_timer_interrupt+0x76/0xa0
     [<ffffffff83c3416c>] apic_timer_interrupt+0x8c/0xa0
     <EOI>
     [<ffffffff83c3239c>] ? _raw_spin_unlock_irqrestore+0x2c/0x60
     [<ffffffff82c8185d>] snd_timer_start1+0xdd/0x670
     [<ffffffff82c87015>] snd_timer_continue+0x45/0x80
     [<ffffffff82c88100>] snd_timer_user_ioctl+0x1030/0x2830
     [<ffffffff8159f3a0>] ? __follow_pte.isra.49+0x430/0x430
     [<ffffffff82c870d0>] ? snd_timer_pause+0x80/0x80
     [<ffffffff815a26fa>] ? do_wp_page+0x3aa/0x1c90
     [<ffffffff815aa4f8>] ? handle_mm_fault+0xbc8/0x27f0
     [<ffffffff815a9930>] ? __pmd_alloc+0x370/0x370
     [<ffffffff82c870d0>] ? snd_timer_pause+0x80/0x80
     [<ffffffff816b0733>] do_vfs_ioctl+0x193/0x1050
     [<ffffffff816b05a0>] ? ioctl_preallocate+0x200/0x200
     [<ffffffff81002f2f>] ? syscall_trace_enter+0x3cf/0xdb0
     [<ffffffff815045ba>] ? __context_tracking_exit.part.4+0x9a/0x1e0
     [<ffffffff81002b60>] ? exit_to_usermode_loop+0x190/0x190
     [<ffffffff82001a97>] ? check_preemption_disabled+0x37/0x1e0
     [<ffffffff81d93889>] ? security_file_ioctl+0x89/0xb0
     [<ffffffff816b167f>] SyS_ioctl+0x8f/0xc0
     [<ffffffff816b15f0>] ? do_vfs_ioctl+0x1050/0x1050
     [<ffffffff81005524>] do_syscall_64+0x1c4/0x4e0
     [<ffffffff83c32b2a>] entry_SYSCALL64_slow_path+0x25/0x25
    Code: e8 fc 42 7b fe 8b 0d 06 8a 50 03 49 0f af cf 48 85 c9 0f 88 7c 01 00 00 48 89 4d a8 e8 e0 42 7b fe 48 8b 45 c0 48 8b 4d a8 48 99 <48> f7 f9 49 01 c7 e8 cb 42 7b fe 48 8b 55 d0 48 b8 00 00 00 00
    RIP  [<ffffffff82c8bd9a>] snd_hrtimer_callback+0x1da/0x3f0
     RSP <ffff88011aa87da8>
    ---[ end trace 6aa380f756a21074 ]---

The problem happens when you call ioctl(SNDRV_TIMER_IOCTL_CONTINUE) on a
completely new/unused timer -- it will have ->sticks == 0, which causes a
divide by 0 in snd_hrtimer_callback().
Signed-off-by: NVegard Nossum <vegard.nossum@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Reuse existing functionality from memdup_user() instead of keeping
duplicate source code.

This issue was detected by using the Coccinelle software.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Acked-by: NVinod Koul <vinod.koul@intel.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Former commits change existent functions so that they don't handle data in
kernel space. Copying from/to userspace is done outside of the functions,
thus no need to change address limit of running task.

This commit obsoletes get_fs()/set_fs() and applies corresponding changes.
Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

In previous commit, a new table for functions with data in kernel space
is added to replace current table.

This commit changes existent functions to fit the table. These functions
are added to the new table and removed from the old table.
Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

ALSA sequencer is designed with two types of clients; application and
kernel. Operations for each ioctl command should handle data in both of
user space and kernel space, while current implementation just allows them
to handle data in user space. Data in kernel space is handled with change
of address limit of running tasks.

This commit adds a new table to map ioctl commands to corresponding
functions. The functions get data in kernel space. Helper functions to
operate kernel and application clients seek entries from the table.
Especially, the helper function for application is responsible for coping
from user space to kernel space or vise versa.
Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

This kernel API is used by kernel implementation. Currently, it's used for
kernel clients of ALSA sequencer, while it can be used for application
clients. The difference is just on address spaces of argument. In short,
this kernel API can be available for application client with data in kernel
space.

This commit adds a document about this.
Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The chmap ctls assigned to PCM streams are freed in the PCM disconnect
callback.  However, since the disconnect callback isn't called when
the card gets freed before registering, the chmap ctls may still be
left assigned.  They are eventually freed together with other ctls,
but it may cause an Oops at pcm_chmap_ctl_private_free(), as the
function refers to the assigned PCM stream, while the PCM objects have
been already freed beforehand.

The fix is to free the chmap ctls also at PCM free callback, not only
at PCM disconnect.
Reported-by: NLaxminath Kasam <b_lkasam@codeaurora.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

snd_ctl_remove() has a notification for the removal event.  It's
superfluous when done during the device got disconnected.  Although
the notification itself is mostly harmless, it may potentially be
harmful, and should be suppressed.  Actually some components PCM may
free ctl elements during the disconnect or free callbacks, thus it's
no theoretical issue.

This patch adds the check of card->shutdown flag for avoiding
unnecessary notifications after (or during) the disconnect.

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

The 'dimen' field in struct snd_ctl_elem_info is used to compose all of
members in the element as multi-dimensional matrix. The field has four
members. Each member represents the width in each dimension level by
element member unit. For example, if the members consist of typical
two dimensional matrix, the dimen[0] represents the number of rows
and dimen[1] represents the number of columns (or vise-versa).

The total members in the matrix should be exactly the same as the number
of members in the element, while current implementation has no validator
of this information. In a view of userspace applications, the information
must be valid so that it cannot cause any bugs such as buffer-over-run.

This commit adds a validator of dimension information for userspace
applications which add new element sets. When they add the element sets
with wrong dimension information, they receive -EINVAL.
Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The user timer tu->qused counter may go to a negative value when
multiple concurrent reads are performed since both the check and the
decrement of tu->qused are done in two individual locked contexts.
This results in bogus read outs, and the endless loop in the
user-space side.

The fix is to move the decrement of the tu->qused counter into the
same spinlock context as the zero-check of the counter.

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

The sequencer client manager reports timestamps in units of unsigned
32-bit seconds/nanoseconds, but that does not suffer from the y2038
overflow because it stores only the delta since the 'last_update'
time was recorded.

However, the use of the do_gettimeofday() function is problematic
and we have to replace it to avoid the overflow on on 32-bit
architectures.

This uses 'struct timespec64' to record 'last_update', and changes
the code to use monotonic timestamps that do not suffer from leap
seconds and settimeofday updates.

As a side-effect, the code can now use the timespec64_sub() helper
and become more readable and also avoid a multiplication to convert
from microseconds to nanoseconds.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Replace the in order struct initialisation style with explicit field
style.

The Coccinelle semantic patch used to make this change is as follows:

@decl@
identifier i1,fld;
type T;
field list[n] fs;
@@

struct i1 {
 fs
 T fld;
 ...};

@@
identifier decl.i1,i2,decl.fld;
expression e;
position bad.p, bad.fix;
@@

struct i1 i2@p = { ...,
+ .fld = e
- e@fix
 ,...};

Also, removed some unnecessary comments.
Signed-off-by: NAmitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Currently, the avail IOCTL doesn't pass any error status, which
means typically on error it simply shows no data available. This
can lead to situations where user-space is waiting indefinitely
for data that will never come as the DSP has suffered an
unrecoverable error.

Add snd_compr_stop_error which end drivers can call to indicate
the stream has suffered an unrecoverable error and stop it. The
avail and poll IOCTLs are then updated to report if the stream is
in an error state to user-space. Allowing the error to propagate
out. Processing of the actual snd_compr_stop needs to be deferred
to a worker thread as the end driver may detect the errors during
an existing operation callback.
Signed-off-by: NCharles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: NVinod Koul <vinod.koul@intel.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

When snd_pcm_add_chmap_ctls() is called to the PCM stream to which a
chmap has been already assigned, it returns as an error due to the
conflicting snd_ctl_add() result.  However, this also clears the
already assigned chmap_kctl field via pcm_chmap_ctl_private_free(),
and becomes inconsistent in the later operation.

This patch adds the check of the conflicting chmap kctl before
actually trying to allocate / assign.  The check failure is treated as
a kernel warning, as the double call of snd_pcm_add_chmap_ctls() is
basically a driver bug and having the stack trace would help
developers to figure out the bad code path.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

A switch statement looks a bit cleaner than an if statement
spread over 3 lines, as such update this to a switch.
Signed-off-by: NCharles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: NVinod Koul <vinod.koul@intel.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

We can't return a negative error code from the poll callback the return
type is unsigned and is checked against the poll specific flags we need
to return POLLERR if we encounter an error.
Signed-off-by: NCharles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: NVinod Koul <vinod.koul@intel.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

stream can't be NULL here as we have just taken the address of it, so no
need for the check.
Signed-off-by: NCharles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: NVinod Koul <vinod.koul@intel.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

We have a function that returns the appropriate flags for the stream
direction, so we should use it.
Signed-off-by: NCharles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: NVinod Koul <vinod.koul@intel.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

We can't return a negative error code from the poll callback the return
type is unsigned and is checked against the poll specific flags we need
to return POLLERR if we encounter an error.
Signed-off-by: NCharles Keepax <ckeepax@opensource.wolfsonmicro.com>
Reviewed-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The stack object “r1” has a total size of 32 bytes. Its field
“event” and “val” both contain 4 bytes padding. These 8 bytes
padding bytes are sent to user without being initialized.
Signed-off-by: NKangjie Lu <kjlu@gatech.edu>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The stack object “r1” has a total size of 32 bytes. Its field
“event” and “val” both contain 4 bytes padding. These 8 bytes
padding bytes are sent to user without being initialized.
Signed-off-by: NKangjie Lu <kjlu@gatech.edu>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The stack object “tread” has a total size of 32 bytes. Its field
“event” and “val” both contain 4 bytes padding. These 8 bytes
padding bytes are sent to user without being initialized.
Signed-off-by: NKangjie Lu <kjlu@gatech.edu>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

dmaengine_pcm currently only supports setups where FIFO reads/writes
correspond to exactly one sample, eg 16-bit sample data is transferred
via 16-bit FIFO accesses, 32-bit data via 32-bit accesses.

This patch adds support for setups with fixed width FIFOs where
multiple samples are packed into a larger word.

For example setups with a 32-bit wide FIFO register that expect
16-bit sample transfers to be done with the left+right sample data
packed into a 32-bit word.

Support for packed transfers is controlled via the
SND_DMAENGINE_PCM_DAI_FLAG_PACK flag in snd_dmaengine_dai_dma_data.flags

If this flag is set dmaengine_pcm doesn't put any restriction on the
supported formats and sets the DMA transfer width to undefined.

This means control over the constraints is now transferred to the DAI
driver and it's responsible to provide proper configuration and
check for possible corner cases that aren't handled by the ALSA core.
Signed-off-by: NMatthias Reichl <hias@horus.com>
Acked-by: NLars-Peter Clausen <lars@metafoo.de>
Tested-by: NMartin Sperl <kernel@martin.sperl.org>
Signed-off-by: NMark Brown <broonie@kernel.org>

This patch tries to address the still remaining issues in ALSA hrtimer
driver:
- Spurious use-after-free was detected in hrtimer callback
- Incorrect rescheduling due to delayed start
- WARN_ON() is triggered in hrtimer_forward() invoked in hrtimer
  callback

The first issue happens only when the new timer is scheduled even
while hrtimer is being closed.  It's related with the second and third
items; since ALSA timer core invokes hw.start callback during hrtimer
interrupt, this may result in the explicit call of hrtimer_start().

Also, the similar problem is seen for the stop; ALSA timer core
invokes hw.stop callback even in the hrtimer handler, too.  Since we
must not call the synced hrtimer_cancel() in such a context, it's just
a hrtimer_try_to_cancel() call that doesn't properly work.

Another culprit of the second and third items is the call of
hrtimer_forward_now() before snd_timer_interrupt().  The timer->stick
value may change during snd_timer_interrupt() call, but this
possibility is ignored completely.

For covering these subtle and messy issues, the following changes have
been done in this patch:
- A new flag, in_callback, is introduced in the private data to
  indicate that the hrtimer handler is being processed.
- Both start and stop callbacks skip when called from (during)
  in_callback flag.
- The hrtimer handler returns properly HRTIMER_RESTART and NORESTART
  depending on the running state now.
- The hrtimer handler reprograms the expiry properly after
  snd_timer_interrupt() call, instead of before.
- The close callback clears running flag and sets in_callback flag
  to block any further start/stop calls.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

There are no users of rtctimer left. Remove its code as this is the
in-kernel user of the legacy PC RTC driver that will hopefully be removed
at some point.
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Currently kill_fasync() is called outside the stream lock in
snd_pcm_period_elapsed().  This is potentially racy, since the stream
may get released even during the irq handler is running.  Although
snd_pcm_release_substream() calls snd_pcm_drop(), this doesn't
guarantee that the irq handler finishes, thus the kill_fasync() call
outside the stream spin lock may be invoked after the substream is
detached, as recently reported by KASAN.

As a quick workaround, move kill_fasync() call inside the stream
lock.  The fasync is rarely used interface, so this shouldn't have a
big impact from the performance POV.

Ideally, we should implement some sync mechanism for the proper finish
of stream and irq handler.  But this oneliner should suffice for most
cases, so far.
Reported-by: NBaozeng Ding <sploving1@gmail.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Treat 32 bit sample width as if it was 24 bits when generating IEC958
channel status bits. On some platforms 24 sample width is problematic
and to get full 24 bit precision a 32 bit format, using only the 24
most significant bits, may have to be used.
Signed-off-by: NJyri Sarha <jsarha@ti.com>
Reviewed-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NMark Brown <broonie@kernel.org>

Add IEC958 channel status helper that gets the audio properties from
snd_pcm_hw_params instead of snd_pcm_runtime. This is needed to
produce the channel status bits already in audio stream configuration
phase.
Signed-off-by: NJyri Sarha <jsarha@ti.com>
Reviewed-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NMark Brown <broonie@kernel.org>