From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2009340B383; Wed, 7 Oct 2026 09:36:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791365823; cv=none; b=YLcAcS/O/38ejL3Q47Vhc36cqeHn5hQ1rt6BOwNNB+4Vo1+Gl5dHXnLJqH1t1xKeDyx+AWFJSIXyYOuXvfaY85Bw+CulBzpVW/sZaMmagmIqwKDU22SKKd5csZJ5P/MG0QPGHee4zNBPMxpDWCjw8087WTCmqIAEN9nCHRB0tAg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791365823; c=relaxed/simple; bh=YqdcpTJqYZjlmX/P/LKvgMu8wTHnl7Gwap2cRMrTaB0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ulRGQ4bT7St5x5GM+IOhZ8Obl95XI1PrvCKNyeUC/oIWyKBBArqTIqGSoUMXsoGMnn+p5lSd1AlMmMao+L9EdbNF9p6VNl1yW+/NFiDIcEtI+rLyDWCHFQ3quNzQTIgqDRP9QlOgjg17hdWSsPpWmhl2V8L0SVccUzxph9UvMxY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de; spf=pass smtp.mailfrom=suse.de; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=uFRVbP4R; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=Em0B5cFG; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=uFRVbP4R; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=Em0B5cFG; arc=none smtp.client-ip=195.135.223.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="uFRVbP4R"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="Em0B5cFG"; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="uFRVbP4R"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="Em0B5cFG" Received: from imap1.dmz-prg2.suse.org (unknown [10.150.64.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 4F06121FDB; Wed, 7 Oct 2026 09:36:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1791365805; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rgLxZv35CgS7g0IWTbXthBD3uAd5BPazCxgcizGnc9s=; b=uFRVbP4RoGUA/E0NlAUnyDHxxwHwB9T6/7BvGX8RJ118j2kahKfSgATuA6ZpF98xMq06zC SdRWALKJO0GVm/ILaeJ7WwDDbFg09lx2cTtfoVVasOVMXdnzF2aSFWK/1abZLSQHabCUEG +HghAQnTsqvFkAzlf4DgoIwt/5+QnM8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1791365805; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rgLxZv35CgS7g0IWTbXthBD3uAd5BPazCxgcizGnc9s=; b=Em0B5cFGYStLewYI96GSFowGcBN5hWH3x0aCfWNZ0Ao/jZIJtUDPE7Ju3sVrZTzxhSI48c j6r8UrQRgcTGWsDg== Authentication-Results: smtp-out1.suse.de; none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1791365805; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rgLxZv35CgS7g0IWTbXthBD3uAd5BPazCxgcizGnc9s=; b=uFRVbP4RoGUA/E0NlAUnyDHxxwHwB9T6/7BvGX8RJ118j2kahKfSgATuA6ZpF98xMq06zC SdRWALKJO0GVm/ILaeJ7WwDDbFg09lx2cTtfoVVasOVMXdnzF2aSFWK/1abZLSQHabCUEG +HghAQnTsqvFkAzlf4DgoIwt/5+QnM8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1791365805; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rgLxZv35CgS7g0IWTbXthBD3uAd5BPazCxgcizGnc9s=; b=Em0B5cFGYStLewYI96GSFowGcBN5hWH3x0aCfWNZ0Ao/jZIJtUDPE7Ju3sVrZTzxhSI48c j6r8UrQRgcTGWsDg== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 7B20213B9C; Wed, 7 Oct 2026 09:36:41 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 9oTPLKgSxmpMDgAAD6G6ig:T9 (envelope-from ); Wed, 07 Oct 2026 09:36:41 +0000 From: Takashi Iwai To: linux-sound@vger.kernel.org Cc: linux-kernel@vger.kernel.org Subject: [PATCH v2 8/8] ALSA: core: Add missing barriers for power_ref vs card->shutdown Date: Wed, 7 Oct 2026 11:36:35 +0200 Message-ID: <20261007093638.1049688-9-tiwai@suse.de> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20261007093638.1049688-1-tiwai@suse.de> References: <20261007093638.1049688-1-tiwai@suse.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Flag: NO X-Spam-Score: -2.80 X-Spam-Level: X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_MISSING_CHARSET(0.50)[]; NEURAL_HAM_SHORT(-0.20)[-0.999]; MIME_GOOD(-0.10)[text/plain]; RCPT_COUNT_TWO(0.00)[2]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:email,imap1.dmz-prg2.suse.org:helo]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FROM_HAS_DN(0.00)[]; MIME_TRACE(0.00)[0:+]; FROM_EQ_ENVFROM(0.00)[]; TO_DN_NONE(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[] snd_power_ref_and_wait() increments card->power_ref and then reads card->shutdown (and the power state) locklessly, while snd_card_disconnect() sets card->shutdown and then waits for power_ref to drop to zero via snd_power_sync_ref(). Due to the missing barrier on both sides, the caller proceeds with shutdown still seen as false, while the disconnect side sees a zero refcount and continues tearing down incorrectly. For addressing the potential race, add smp_mb__after_atomic() after the refcount increment and smp_mb() before snd_power_sync_ref() in snd_card_disconnect(). Fixes: e94fdbd7b25d ("ALSA: control: Track in-flight control read/write/tlv accesses") Reported-by: Sashiko Assisted-by: LLM Signed-off-by: Takashi Iwai --- sound/core/init.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/sound/core/init.c b/sound/core/init.c index 7878c0e6103c..dbe2acfa59fe 100644 --- a/sound/core/init.c +++ b/sound/core/init.c @@ -535,6 +535,8 @@ void snd_card_disconnect(struct snd_card *card) clear_bit(card->number, snd_cards_lock); } + /* order card->shutdown store against power_ref read */ + smp_mb(); snd_power_sync_ref(card); } EXPORT_SYMBOL(snd_card_disconnect); @@ -1152,6 +1154,8 @@ EXPORT_SYMBOL(snd_card_file_remove); int snd_power_ref_and_wait(struct snd_card *card) { snd_power_ref(card); + /* order power_ref increment against card->shutdown read */ + smp_mb__after_atomic(); if (snd_power_get_state(card) != SNDRV_CTL_POWER_D0) { wait_event_cmd(card->power_sleep, card->shutdown || -- 2.55.0