kernel/linux.git/sound/core/misc.c, branch v6.18.33

ALSA: core: Serialize deferred fasync state checks

2026-05-14T13:30:13+00:00

commit 5337213381df578058e2e41da93cbd0e4639935f upstream. snd_fasync_helper() updates fasync->on under snd_fasync_lock, and snd_fasync_work_fn() now also evaluates fasync->on under the same lock. snd_kill_fasync() still tests the flag before taking the lock, leaving an unsynchronized read against FASYNC enable/disable updates. Move the enabled-state check into the locked section. Also clear fasync->on under snd_fasync_lock in snd_fasync_free() before unlinking the pending entry. Together with the locked sender-side check, this publishes teardown before flushing the deferred work and prevents a racing sender from requeueing the entry after free has started. Fixes: ef34a0ae7a26 ("ALSA: core: Add async signal helpers") Fixes: 8146cd333d23 ("ALSA: core: Fix potential data race at fasync handling") Cc: stable@vger.kernel.org Signed-off-by: Cássio Gabriel Link: https://patch.msgid.link/20260506-alsa-core-fasync-on-lock-v1-1-ea48c77d6ca4@gmail.com Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: core: Fix potential data race at fasync handling

2026-05-07T04:11:42+00:00

commit 8146cd333d235ed32d48bb803fdf743472d7c783 upstream. In snd_fasync_work_fn(), which is the offload work for traversing and processing the pending fasync list, the call of kill_fasync() is done outside the snd_fasync_lock for avoiding deadlocks. The problem is that its the references of fasync->on, fasync->signal and fasync->poll are done there also outside the lock. Since these may be modified by snd_kill_fasync() call concurrently from other process, inconsistent values might be passed to kill_fasync(). Although there shouldn't be critical UAF, it's still better to be addressed. This patch moves the kill_fasync() argument evaluations inside the snd_fasync_lock for avoiding the data races above. The handling in fasync->on flag is optimized in the loop to skip directly. Also, for more clarity, snd_fasync_free() takes the lock and unlink the pending entry more directly instead of clearing fasync->on flag. Reported-by: Jake Lamberson Fixes: ef34a0ae7a26 ("ALSA: core: Add async signal helpers") Cc: Link: https://patch.msgid.link/20260420061721.3253644-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman

ALSA: misc: Use guard() for spin locks

2025-09-01T11:54:28+00:00

Clean up the code using guard() for spin locks. Merely code refactoring, and no behavior change. Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20250829151335.7342-20-tiwai@suse.de

ALSA: core: Drop snd_print stuff and co

2024-08-08T05:49:47+00:00

Now that all users of snd_print*() are gone, let's drop the functions completely. This also makes CONFIG_SND_VERBOSE_PRINTK redundant, and it's dropped, too. Reviewed-by: Jaroslav Kysela Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20240807133452.9424-55-tiwai@suse.de

ALSA: core: Add async signal helpers

2022-07-29T10:57:10+00:00

Currently the call of kill_fasync() from an interrupt handler might lead to potential spin deadlocks, as spotted by syzkaller. Unfortunately, it's not so trivial to fix this lock chain as it's involved with the tasklist_lock that is touched in allover places. As a temporary workaround, this patch provides the way to defer the async signal notification in a work. The new helper functions, snd_fasync_helper() and snd_kill_faync() are replacements for fasync_helper() and kill_fasync(), respectively. In addition, snd_fasync_free() needs to be called at the destructor of the relevant file object. Link: https://lore.kernel.org/r/20220728125945.29533-2-tiwai@suse.de Signed-off-by: Takashi Iwai

ALSA: core: Fix SSID quirk lookup for subvendor=0

2022-01-17T08:59:32+00:00

Some weird devices set the codec SSID vendor ID 0, and snd_pci_quirk_lookup_id() loop aborts at the point although it should still try matching with the SSID device ID. This resulted in a missing quirk for some old Macs. Fix the loop termination condition to check both subvendor and subdevice. Fixes: 73355ddd8775 ("ALSA: hda: Code refactoring snd_hda_pick_fixup()") Cc: BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215495 Link: https://lore.kernel.org/r/20220116082838.19382-1-tiwai@suse.de Signed-off-by: Takashi Iwai

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

2019-05-30T18:26:35+00:00

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 Reviewed-by: Allison Randal Reviewed-by: Richard Fontana Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman

ALSA: core: Follow standard EXPORT_SYMBOL() declarations

2017-06-16T14:19:16+00:00

Just a tidy up to follow the standard EXPORT_SYMBOL*() declarations in order to improve grep-ability. - Move EXPORT_SYMBOL*() to the position right after its definition - Remove superfluous blank line before EXPORT_SYMBOL*() lines Signed-off-by: Takashi Iwai

printk/sound: handle more message headers

2016-12-13T02:55:09+00:00

Commit 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing continuation lines") allows to define more message headers for a single message. The motivation is that continuous lines might get mixed. Therefore it make sense to define the right log level for every piece of a cont line. This patch allows to copy only the real message level. We should ignore KERN_CONT because is added for each message. By other words, we want to know where each piece of the line comes from. [pmladek@suse.com: fix a check of the valid message level] Link: http://lkml.kernel.org/r/20161111183444.GE2145@dhcp128.suse.cz Link: http://lkml.kernel.org/r/1478695291-12169-5-git-send-email-pmladek@suse.com Signed-off-by: Petr Mladek Cc: Joe Perches Cc: Sergey Senozhatsky Cc: Steven Rostedt Cc: Jason Wessel Cc: Jaroslav Kysela Cc: Takashi Iwai Cc: Chris Mason Cc: Josef Bacik Cc: David Sterba Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ALSA: Allow pass NULL dev for snd_pci_quirk_lookup()

2014-10-08T10:08:38+00:00

Add a NULL check in snd_pci_quirk_lookup() so that NULL can be passed as a pci_dev pointer. This fixes the possible NULL dereferences in HD-audio drivers. Reported-by: Dan Carpenter Signed-off-by: Takashi Iwai