kernel/linux.git/sound/core/init.c, branch v6.1.175

ALSA: core: add isascii() check to card ID generator

2024-10-17T13:21:52+00:00

commit d278a9de5e1837edbe57b2f1f95a104ff6c84846 upstream. The card identifier should contain only safe ASCII characters. The isalnum() returns true also for characters for non-ASCII characters. Link: https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/4135 Link: https://lore.kernel.org/linux-sound/yk3WTvKkwheOon_LzZlJ43PPInz6byYfBzpKkbasww1yzuiMRqn7n6Y8vZcXB-xwFCu_vb8hoNjv7DTNwH5TWjpEuiVsyn9HPCEXqwF4120=@protonmail.com/ Cc: stable@vger.kernel.org Reported-by: Barnabás Pőcze Signed-off-by: Jaroslav Kysela Link: https://patch.msgid.link/20241002194649.1944696-1-perex@perex.cz Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: core: Remove debugfs at disconnection

2024-06-12T09:03:55+00:00

[ Upstream commit 495000a38634e640e2fd02f7e4f1512ccc92d770 ] The card-specific debugfs entries are removed at the last stage of card free phase, and it's performed after synchronization of the closes of all opened fds. This works fine for most cases, but it can be potentially problematic for a hotplug device like USB-audio. Due to the nature of snd_card_free_when_closed(), the card free isn't called immediately after the driver removal for a hotplug device, but it's left until the last fd is closed. It implies that the card debugfs entries also remain. Meanwhile, when a new device is inserted before the last close and the very same card slot is assigned, the driver tries to create the card debugfs root again on the very same path. This conflicts with the remaining entry, and results in the kernel warning such as: debugfs: Directory 'card0' with parent 'sound' already present! with the missing debugfs entry afterwards. For avoiding such conflicts, remove debugfs entries at the device disconnection phase instead. The jack kctl debugfs entries get removed in snd_jack_dev_disconnect() instead of each kctl private_free. Fixes: 2d670ea2bd53 ("ALSA: jack: implement software jack injection via debugfs") Link: https://lore.kernel.org/r/20240524151256.32521-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin

ALSA: Fix deadlocks with kctl removals at disconnection

2024-06-12T09:02:58+00:00

commit 87988a534d8e12f2e6fc01fe63e6c1925dc5307c upstream. In snd_card_disconnect(), we set card->shutdown flag at the beginning, call callbacks and do sync for card->power_ref_sleep waiters at the end. The callback may delete a kctl element, and this can lead to a deadlock when the device was in the suspended state. Namely: * A process waits for the power up at snd_power_ref_and_wait() in snd_ctl_info() or read/write() inside card->controls_rwsem. * The system gets disconnected meanwhile, and the driver tries to delete a kctl via snd_ctl_remove*(); it tries to take card->controls_rwsem again, but this is already locked by the above. Since the sleeper isn't woken up, this deadlocks. An easy fix is to wake up sleepers before processing the driver disconnect callbacks but right after setting the card->shutdown flag. Then all sleepers will abort immediately, and the code flows again. So, basically this patch moves the wait_event() call at the right timing. While we're at it, just to be sure, call wait_event_all() instead of wait_event(), although we don't use exclusive events on this queue for now. Link: https://bugzilla.kernel.org/show_bug.cgi?id=218816 Cc: Reviewed-by: Jaroslav Kysela Link: https://lore.kernel.org/r/20240510101424.6279-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: core: Fix NULL module pointer assignment at card init

2024-06-12T09:02:57+00:00

commit 39381fe7394e5eafac76e7e9367e7351138a29c1 upstream. The commit 81033c6b584b ("ALSA: core: Warn on empty module") introduced a WARN_ON() for a NULL module pointer passed at snd_card object creation, and it also wraps the code around it with '#ifdef MODULE'. This works in most cases, but the devils are always in details. "MODULE" is defined when the target code (i.e. the sound core) is built as a module; but this doesn't mean that the caller is also built-in or not. Namely, when only the sound core is built-in (CONFIG_SND=y) while the driver is a module (CONFIG_SND_USB_AUDIO=m), the passed module pointer is ignored even if it's non-NULL, and card->module remains as NULL. This would result in the missing module reference up/down at the device open/close, leading to a race with the code execution after the module removal. For addressing the bug, move the assignment of card->module again out of ifdef. The WARN_ON() is still wrapped with ifdef because the module can be really NULL when all sound drivers are built-in. Note that we keep 'ifdef MODULE' for WARN_ON(), otherwise it would lead to a false-positive NULL module check. Admittedly it won't catch perfectly, i.e. no check is performed when CONFIG_SND=y. But, it's no real problem as it's only for debugging, and the condition is pretty rare. Fixes: 81033c6b584b ("ALSA: core: Warn on empty module") Reported-by: Xu Yang Closes: https://lore.kernel.org/r/20240520170349.2417900-1-xu.yang_2@nxp.com Cc: Signed-off-by: Takashi Iwai Tested-by: Xu Yang Link: https://lore.kernel.org/r/20240522070442.17786-1-tiwai@suse.de Signed-off-by: Greg Kroah-Hartman

ALSA: core: Fix double-free at snd_card_new()

2022-09-19T12:36:06+00:00

During the code change to add the support for devres-managed card instance, we put an explicit kfree(card) call at the error path in snd_card_new(). This is needed for the early error path before the card is initialized with the device, but is rather superfluous and causes a double-free at the error path after the card instance is initialized, as the destructor of the card object already contains a kfree() call. This patch fixes the double-free situation by removing the superfluous kfree(). Meanwhile we need to call kfree() explicitly for the early error path, so it's added there instead. Fixes: e8ad415b7a55 ("ALSA: core: Add managed card creation") Reported-by: Rondreis Cc: Link: https://lore.kernel.org/r/CAB7eexL1zBnB636hwS27d-LdPYZ_R1-5fJS_h=ZbCWYU=UPWJg@mail.gmail.com Link: https://lore.kernel.org/r/20220919123516.28222-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: core: Replace scnprintf() with sysfs_emit()

2022-08-02T14:03:45+00:00

sysfs_emit() is a new helper to simplify the sysfs string output. Replace the open-code with this new helper. Link: https://lore.kernel.org/r/20220801165639.26030-5-tiwai@suse.de Signed-off-by: Takashi Iwai

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

2022-07-13T11:42:38+00:00

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

ALSA: control: Use xarray for faster lookups

2022-06-15T05:44:55+00:00

The control elements are managed in a single linked list and we traverse the whole list for matching each numid or ctl id per every inquiry of a control element. This is OK-ish for a small number of elements but obviously it doesn't scale. Especially the matching with the ctl id takes time because it checks each field of the snd_ctl_id element, e.g. the name string is matched with strcmp(). This patch adds the hash tables with Xarray for improving the lookup speed of a control element. There are two xarray tables added to the card; one for numid and another for ctl id. For the numid, we use the numid as the index, while for the ctl id, we calculate a hash key. The lookup is done via a single xa_load() execution. As long as the given control element is found on the Xarray table, that's fine, we can give back a quick lookup result. The problem is when no entry hits on the table, and for this case, we have a slight optimization. Namely, the driver checks whether we had a collision on Xarray table, and do a fallback search (linear lookup of the full entries) only if a hash key collision happened beforehand. So, in theory, the inquiry for a non-existing element might take still time even with this patch in a worst case, but this must be pretty rare. The feature is enabled via CONFIG_SND_CTL_FAST_LOOKUP, which is turned on as default. For simplicity, the option can be turned off only when CONFIG_EXPERT is set ("You are expert? Then you manage 1000 knobs"). Link: https://lore.kernel.org/r/20211028130027.18764-1-tiwai@suse.de Link: https://lore.kernel.org/r/20220609180504.775-1-tiwai@suse.de Link: https://lore.kernel.org/all/cover.1653813866.git.quic_rbankapu@quicinc.com/ Link: https://lore.kernel.org/r/20220610064537.18660-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: core: Add snd_card_free_on_error() helper

2022-04-12T09:47:57+00:00

This is a small helper function to handle the error path more easily when an error happens during the probe for the device with the device-managed card. Since devres releases in the reverser order of the creations, usually snd_card_free() gets called at the last in the probe error path unless it already reached snd_card_register() calls. Due to this nature, when a driver expects the resource releases in card->private_free, this might be called too lately. As a workaround, one should call the probe like: static int __some_probe(...) { // do real probe.... } static int some_probe(...) { return snd_card_free_on_error(dev, __some_probe(dev, ...)); } so that the snd_card_free() is called explicitly at the beginning of the error path from the probe. This function will be used in the upcoming fixes to address the regressions by devres usages. Fixes: e8ad415b7a55 ("ALSA: core: Add managed card creation") Cc: Link: https://lore.kernel.org/r/20220412093141.8008-2-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: core: Simplify snd_power_ref_and_wait() with the standard macro

2022-01-19T16:26:04+00:00

Use wait_event_cmd() macro and simplify snd_power_ref_wait() implementation. This may also cover possible races in the current open code, too. Reviewed-by: Jaroslav Kysela Link: https://lore.kernel.org/r/20220119091050.30125-1-tiwai@suse.de Signed-off-by: Takashi Iwai