ALSA: info: Fix potential deadlock at disconnection

commit c7a60651953359f98dbf24b43e1bf561e1573ed4 upstream.

As reported recently, ALSA core info helper may cause a deadlock at
the forced device d

ALSA: info: Fix potential deadlock at disconnection

commit c7a60651953359f98dbf24b43e1bf561e1573ed4 upstream.

As reported recently, ALSA core info helper may cause a deadlock at
the forced device disconnection during the procfs operation.

The proc_remove() (that is called from the snd_card_disconnect()
helper) has a synchronization of the pending procfs accesses via
wait_for_completion(). Meanwhile, ALSA procfs helper takes the global
mutex_lock(&info_mutex) at both the proc_open callback and
snd_card_info_disconnect() helper. Since the proc_open can't finish
due to the mutex lock, wait_for_completion() never returns, either,
hence it deadlocks.

TASK#1 TASK#2
proc_reg_open()
takes use_pde()
snd_info_text_entry_open()
snd_card_disconnect()
snd_info_card_disconnect()
takes mutex_lock(&info_mutex)
proc_remove()
wait_for_completion(unused_pde)
... waiting task#1 closes
mutex_lock(&info_mutex)
=> DEADLOCK

This patch is a workaround for avoiding the deadlock scenario above.

The basic strategy is to move proc_remove() call outside the mutex
lock. proc_remove() can work gracefully without extra locking, and it
can delete the tree recursively alone. So, we call proc_remove() at
snd_info_card_disconnection() at first, then delete the rest resources
recursively within the info_mutex lock.

After the change, the function snd_info_disconnect() doesn't do
disconnection by itself any longer, but it merely clears the procfs
pointer. So rename the function to snd_info_clear_entries() for
avoiding confusion.

The similar change is applied to snd_info_free_entry(), too. Since
the proc_remove() is called only conditionally with the non-NULL
entry->p, it's skipped after the snd_info_clear_entries() call.

Reported-by: Shinhyung Kang <s47.kang@samsung.com>
Closes: https://lore.kernel.org/r/664457955.21699345385931.JavaMail.epsvc@epcpadp4
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20231109141954.4283-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

ALSA: info: Fix llseek return value when using callback

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset = callback();
goto out;
}
...
offset = some other value

ALSA: info: Fix llseek return value when using callback

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset = callback();
goto out;
}
...
offset = some other value in case of no callback;
ret = offset;
out:
return ret;

which causes the snd_info_entry_llseek() to return -EINVAL when there is
callback handler. Fix this by setting "ret" directly to callback return
value before jumping to "out".

Fixes: 73029e0ff18d ("ALSA: info - Implement common llseek for binary mode")
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220817124924.3974577-1-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

show more ...

ALSA: core: Fix missing return value comments for kernel docs

Each kernel doc comment expects the definition of the return value in
a proper format. This patch adds or fixes the missing entries for

ALSA: core: Fix missing return value comments for kernel docs

Each kernel doc comment expects the definition of the return value in
a proper format. This patch adds or fixes the missing entries for the
remaining ALSA core API functions.

Link: https://lore.kernel.org/r/20220713104759.4365-8-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

show more ...

proc: remove PDE_DATA() completely

Remove PDE_DATA() completely and replace it with pde_data().

[akpm@linux-foundation.org: fix naming clash in drivers/nubus/proc.c]
[akpm@linux-foundation.org: now

proc: remove PDE_DATA() completely

Remove PDE_DATA() completely and replace it with pde_data().

[akpm@linux-foundation.org: fix naming clash in drivers/nubus/proc.c]
[akpm@linux-foundation.org: now fix it properly]

Link: https://lkml.kernel.org/r/20211124081956.87711-2-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Alexey Gladkov <gladkov.alexey@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset =

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset = callback();
goto out;
}
...
offset = some other value in case of no callback;
ret = offset;
out:
return ret;

which causes the snd_info_entry_llseek() to return -EINVAL when there is
callback handler. Fix this by setting "ret" directly to callback return
value before jumping to "out".

Fixes: 73029e0ff18d ("ALSA: info - Implement common llseek for binary mode")
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220817124924.3974577-1-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset =

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset = callback();
goto out;
}
...
offset = some other value in case of no callback;
ret = offset;
out:
return ret;

which causes the snd_info_entry_llseek() to return -EINVAL when there is
callback handler. Fix this by setting "ret" directly to callback return
value before jumping to "out".

Fixes: 73029e0ff18d ("ALSA: info - Implement common llseek for binary mode")
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220817124924.3974577-1-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset =

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset = callback();
goto out;
}
...
offset = some other value in case of no callback;
ret = offset;
out:
return ret;

which causes the snd_info_entry_llseek() to return -EINVAL when there is
callback handler. Fix this by setting "ret" directly to callback return
value before jumping to "out".

Fixes: 73029e0ff18d ("ALSA: info - Implement common llseek for binary mode")
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220817124924.3974577-1-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset =

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset = callback();
goto out;
}
...
offset = some other value in case of no callback;
ret = offset;
out:
return ret;

which causes the snd_info_entry_llseek() to return -EINVAL when there is
callback handler. Fix this by setting "ret" directly to callback return
value before jumping to "out".

Fixes: 73029e0ff18d ("ALSA: info - Implement common llseek for binary mode")
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220817124924.3974577-1-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset =

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset = callback();
goto out;
}
...
offset = some other value in case of no callback;
ret = offset;
out:
return ret;

which causes the snd_info_entry_llseek() to return -EINVAL when there is
callback handler. Fix this by setting "ret" directly to callback return
value before jumping to "out".

Fixes: 73029e0ff18d ("ALSA: info - Implement common llseek for binary mode")
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220817124924.3974577-1-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset =

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset = callback();
goto out;
}
...
offset = some other value in case of no callback;
ret = offset;
out:
return ret;

which causes the snd_info_entry_llseek() to return -EINVAL when there is
callback handler. Fix this by setting "ret" directly to callback return
value before jumping to "out".

Fixes: 73029e0ff18d ("ALSA: info - Implement common llseek for binary mode")
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220817124924.3974577-1-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset =

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset = callback();
goto out;
}
...
offset = some other value in case of no callback;
ret = offset;
out:
return ret;

which causes the snd_info_entry_llseek() to return -EINVAL when there is
callback handler. Fix this by setting "ret" directly to callback return
value before jumping to "out".

Fixes: 73029e0ff18d ("ALSA: info - Implement common llseek for binary mode")
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220817124924.3974577-1-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset =

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset = callback();
goto out;
}
...
offset = some other value in case of no callback;
ret = offset;
out:
return ret;

which causes the snd_info_entry_llseek() to return -EINVAL when there is
callback handler. Fix this by setting "ret" directly to callback return
value before jumping to "out".

Fixes: 73029e0ff18d ("ALSA: info - Implement common llseek for binary mode")
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220817124924.3974577-1-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset =

ALSA: info: Fix llseek return value when using callback

commit 9be080edcca330be4af06b19916c35227891e8bc upstream.

When using callback there was a flow of

ret = -EINVAL
if (callback) {
offset = callback();
goto out;
}
...
offset = some other value in case of no callback;
ret = offset;
out:
return ret;

which causes the snd_info_entry_llseek() to return -EINVAL when there is
callback handler. Fix this by setting "ret" directly to callback return
value before jumping to "out".

Fixes: 73029e0ff18d ("ALSA: info - Implement common llseek for binary mode")
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220817124924.3974577-1-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

isystem: trim/fixup stdarg.h and other headers

Delete/fixup few includes in anticipation of global -isystem compile
option removal.

Note: crypto/aegis128-neon-inner.c keeps <stddef.h> due to redefi

isystem: trim/fixup stdarg.h and other headers

Delete/fixup few includes in anticipation of global -isystem compile
option removal.

Note: crypto/aegis128-neon-inner.c keeps <stddef.h> due to redefinition
of uintptr_t error (one definition comes from <stddef.h>, another from
<linux/types.h>).

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

show more ...

ALSA: info: Drop WARN_ON() from buffer NULL sanity check

snd_info_get_line() has a sanity check of NULL buffer -- both buffer
itself being NULL and buffer->buffer being NULL. Basically both
checks

ALSA: info: Drop WARN_ON() from buffer NULL sanity check

snd_info_get_line() has a sanity check of NULL buffer -- both buffer
itself being NULL and buffer->buffer being NULL. Basically both
checks are valid and necessary, but the problem is that it's with
snd_BUG_ON() macro that triggers WARN_ON(). The latter condition
(NULL buffer->buffer) can be met arbitrarily by user since the buffer
is allocated at the first write, so it means that user can trigger
WARN_ON() at will.

This patch addresses it by simply moving buffer->buffer NULL check out
of snd_BUG_ON() so that spurious WARNING is no longer triggered.

Reported-by: syzbot+e42d0746c3c3699b6061@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200717084023.5928-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

show more ...

ALSA: info: remove redundant assignment to variable c

Variable c is being assigned with the value -1 that is never read,
it is assigned a new value in a following while-loop. The assignment
is redun

ALSA: info: remove redundant assignment to variable c

Variable c is being assigned with the value -1 that is never read,
it is assigned a new value in a following while-loop. The assignment
is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20200208224206.38540-1-colin.king@canonical.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

show more ...

proc: convert everything to "struct proc_ops"

The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in
seq_file.h.

Conversion rule is:

llseek => proc_lseek
unlocked_ioctl => proc_ioctl

proc: convert everything to "struct proc_ops"

The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in
seq_file.h.

Conversion rule is:

llseek => proc_lseek
unlocked_ioctl => proc_ioctl

xxx => proc_xxx

delete ".owner = THIS_MODULE" line

[akpm@linux-foundation.org: fix drivers/isdn/capi/kcapi_proc.c]
[sfr@canb.auug.org.au: fix kernel/sched/psi.c]
Link: http://lkml.kernel.org/r/20200122180545.36222f50@canb.auug.org.au
Link: http://lkml.kernel.org/r/20191225172546.GB13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

show more ...

ALSA: info: More constifications

Apply const prefix to the string array and its callers.

Just for minor optimization and no functional changes.

Link: https://lore.kernel.org/r/20200105144823.29547

ALSA: info: More constifications

Apply const prefix to the string array and its callers.

Just for minor optimization and no functional changes.

Link: https://lore.kernel.org/r/20200105144823.29547-39-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

show more ...

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of th

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

ALSA: info: Fix racy addition/deletion of nodes

The ALSA proc helper manages the child nodes in a linked list, but its
addition and deletion is done without any lock. This leads to a
corruption if

ALSA: info: Fix racy addition/deletion of nodes

The ALSA proc helper manages the child nodes in a linked list, but its
addition and deletion is done without any lock. This leads to a
corruption if they are operated concurrently. Usually this isn't a
problem because the proc entries are added sequentially in the driver
probe procedure itself. But the card registrations are done often
asynchronously, and the crash could be actually reproduced with
syzkaller.

This patch papers over it by protecting the link addition and deletion
with the parent's mutex. There is "access" mutex that is used for the
file access, and this can be reused for this purpose as well.

Reported-by: syzbot+48df349490c36f9f54ab@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

show more ...

ALSA: info: Move card id proc creation into info.c

The creation of card's id proc file can be moved gracefully into
info.c. Also, the assignment of card->proc_id is superfluous and can
be dropped.

ALSA: info: Move card id proc creation into info.c

The creation of card's id proc file can be moved gracefully into
info.c. Also, the assignment of card->proc_id is superfluous and can
be dropped. So let's do it.

Basically this is no functional change but code refactoring, but one
potential behavior change is that now it returns properly the error
code from snd_info_card_register(), which is a good thing (tm).

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

show more ...

ALSA: info: Minor optimization

Just a minor code optimization to reduce the source code size
slightly. No functional changes.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi I

ALSA: info: Minor optimization

Just a minor code optimization to reduce the source code size
slightly. No functional changes.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

show more ...

ALSA: info: Drop unused snd_info_entry.card field

It's referred only in snd_card_id_read() which can receive the card
object via private_data.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-o

ALSA: info: Drop unused snd_info_entry.card field

It's referred only in snd_card_id_read() which can receive the card
object via private_data.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

show more ...

ALSA: info: Add standard helpers for card proc file entries

Two new helper functions are added here for cleaning up the existing
lengthy calls.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-

ALSA: info: Add standard helpers for card proc file entries

Two new helper functions are added here for cleaning up the existing
lengthy calls.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

show more ...

ALSA: info: Always register entries recursively

Make sure that all children entries are registered by a single call of
snd_info_register(). OTOH, don't register if a parent isn't
registered yet.

T

ALSA: info: Always register entries recursively

Make sure that all children entries are registered by a single call of
snd_info_register(). OTOH, don't register if a parent isn't
registered yet.

This allows us to create the whole procfs tree in a shot at the last
stage of card registration phase in a later patch.

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

show more ...