kernel/linux.git/sound/core/init.c, branch v7.2-rc1

ALSA: core: Fix unintuitive behavior of snd_power_ref_and_wait()

2026-06-14T15:31:54+00:00

snd_power_ref_and_wait() takes the power refcount and doesn't leave it no matter whether it returns an error or not. However, the majority of callers don't expect but just returns without unreferencing in the caller side upon errors. For addressing the potential refcount unbalance, rather correct the behavior of snd_power_ref_wait() to unreference upon returning an error. Note that the problem above is likely negligible; the function returns an error only when the sound card is being shutdown, hence it doesn't matter about the power refcount any longer at such a state. Fixes: e94fdbd7b25d ("ALSA: control: Track in-flight control read/write/tlv accesses") Reported-by: WenTao Liang Closes: https://lore.kernel.org/20260612022121.14329-1-vulab@iscas.ac.cn Link: https://patch.msgid.link/20260614090507.772540-1-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: core: Use the new helper for the power refcount

2026-06-11T07:34:09+00:00

Replace the open code for managing the power refcount in the snd_card object with the new helper functions. Only a code cleanup, no functional changes. Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20260610154538.51076-3-tiwai@suse.de

ALSA: core: Use flexible array for card private data

2026-06-01T09:29:02+00:00

snd_card_new() and snd_devm_card_new() allocate struct snd_card together with optional driver-private storage. The storage is currently described only by open-coded sizeof(*card) + extra_size arithmetic, and snd_card_init() reaches it by manually adding sizeof(struct snd_card) to the card pointer. Make the trailing storage explicit with a flexible array member. Use kzalloc_flex() for the regular allocation path and struct_size() for the devres allocation size. This documents the layout and avoids open-coded variable-size object arithmetic. Align the flexible array to unsigned long long so the driver-private area does not become less aligned than the old sizeof(struct snd_card) tail address on 32-bit ABIs. Signed-off-by: Cássio Gabriel Link: https://patch.msgid.link/20260531-alsa-card-private-flex-array-v2-1-e4ff67f5bd23@gmail.com Signed-off-by: Takashi Iwai

ALSA: control: Verify put() result when in debug mode

2026-02-28T08:32:39+00:00

The put() operation is expected to return: 1) 0 on success if no changes were made 2) 1 on success if changes were made 3) error code otherwise Currently 2) is usually ignored when writing control-operations. While forcing compliance is not an option right now, make it easier for developers to adhere to the expectations and notice problems by logging them when CONFIG_SND_CTL_DEBUG is enabled. Due to large size of struct snd_ctl_elem_value, 'value_buf' is provided as a reusable buffer for kctl->put() verification. This prevents exhausting the stack when verifying the operation. >From user perspective, patch introduces a new trace/events category 'snd_ctl' containing a single 'snd_ctl_put' event type. Log sample: amixer-1086 [003] ..... 8.035939: snd_ctl_put: success: expected=0, actual=0 for ctl numid=1, iface=MIXER, name='Master Playback Volume', index=0, device=0, subdevice=0, card=0 amixer-1087 [003] ..... 8.938721: snd_ctl_put: success: expected=1, actual=1 for ctl numid=1, iface=MIXER, name='Master Playback Volume', index=0, device=0, subdevice=0, card=0 amixer-1088 [003] ..... 9.631470: snd_ctl_put: success: expected=1, actual=1 for ctl numid=1, iface=MIXER, name='Master Playback Volume', index=0, device=0, subdevice=0, card=0 amixer-1089 [000] ..... 9.636786: snd_ctl_put: fail: expected=1, actual=0 for ctl numid=5, iface=MIXER, name='Loopback Mute', index=0, device=0, subdevice=0, card=0 Signed-off-by: Cezary Rojewski Reviewed-by: Mark Brown Reviewed-by: Jaroslav Kysela Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20260224205619.584795-1-cezary.rojewski@intel.com

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

ALSA: core: Copy string more safely

2025-07-11T07:53:36+00:00

Replace the remaining strcpy() and sprintf() usages in the ALSA core code with the safer versions. The first strcpy() points actually to card->id, hence just use strscpy() with card->id instead. The append of suffix string is slightly rewritten so that we can use scnprintf() and strscpy(). Only for safety, no actual behavior change. Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20250710100727.22653-104-tiwai@suse.de

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

2024-10-03T07:16:58+00:00

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

ALSA: control: Rename ctl_files_rwlock to controls_rwlock

2024-08-09T12:24:55+00:00

We'll re-use the existing rwlock for the protection of control list lookup, too, and now rename it to a more generic name. This is a preliminary change, only the rename of the struct field here, no functional changes. Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20240809104234.8488-2-tiwai@suse.de

ALSA: core: Remove debugfs at disconnection

2024-05-27T07:28:21+00:00

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