From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D10ED212FAD for ; Wed, 13 May 2026 13:53:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778680422; cv=none; b=uDotQ4KYKBJ35L6gtppGcemj4LoWI/fOaZDGRrhLQEj9AFv7NS74KTiGdYAkswoxExJe1AKjRqJ3nMOVW1kWD3VH74mOCh9jpoFieS6jNsqNZ4a9lvP+OdLv6c1foNSOOxYCmIu2De2lahxU6wi5PkicdoZOcJemFggGeIuk9o0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778680422; c=relaxed/simple; bh=joELe70LeB0AwBIVGPIRRJqDCL+BqHwKV36Svk7GFJo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=GfN3m7tOjgHtahCaLy5Grl+467cfI2VhIujlSVjQ6fn8CrAqrqf1GntOwydfhg2lN43GxKXfchJrLQtokMzotzzXVC+sOMQpORexa6AAMqgZozDzowGJuYesaRDTmiPGEezYrPTsuxbBRyJTn/Dz7EXqy0JW2e8PT/DJPogr/SA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=L3GPXcZZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="L3GPXcZZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F4CCC19425; Wed, 13 May 2026 13:53:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778680422; bh=joELe70LeB0AwBIVGPIRRJqDCL+BqHwKV36Svk7GFJo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=L3GPXcZZznzXDfh51q71kK3+775KCzrzotxpoek9QjfHI8IXfFOG+B9Ic8VJNGYpD z4bHN5Se89Zvyk9+sjwPy5S0Iisd5ZMqruEd9t8g4Tt4QK2pPWSla/LZBWgBUU0K5v bB5Cknz+tOmnpq++IL2rBUa917aEEcAritoekgFVplBiGFgqWRuMORBuR5dp5YV6aB VqvFsbd2/OGAxYWtZmQVA3AhVQWppURf8hiVA8u9T11pzjayPzgG4j2TUVyPZvbmIf PTuflJXFwSAtSk+nvbqv0ANQ1DjquqGN9Fe8p+y7r28Pee4Fr+WoMi1Jb3iRexSsQN c4Naxdp9nnRvQ== From: Sasha Levin To: stable@vger.kernel.org Cc: =?UTF-8?q?C=C3=A1ssio=20Gabriel?= , Takashi Iwai , Sasha Levin Subject: [PATCH 6.12.y 2/2] ALSA: core: Serialize deferred fasync state checks Date: Wed, 13 May 2026 09:53:39 -0400 Message-ID: <20260513135339.3740733-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260513135339.3740733-1-sashal@kernel.org> References: <2026051248-upcountry-culminate-b7a5@gregkh> <20260513135339.3740733-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Cássio Gabriel [ Upstream commit 5337213381df578058e2e41da93cbd0e4639935f ] 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: Sasha Levin --- sound/core/misc.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/sound/core/misc.c b/sound/core/misc.c index 5aca09edf9718..833124c8e4fa8 100644 --- a/sound/core/misc.c +++ b/sound/core/misc.c @@ -148,9 +148,11 @@ EXPORT_SYMBOL_GPL(snd_fasync_helper); void snd_kill_fasync(struct snd_fasync *fasync, int signal, int poll) { - if (!fasync || !fasync->on) + if (!fasync) return; guard(spinlock_irqsave)(&snd_fasync_lock); + if (!fasync->on) + return; fasync->signal = signal; fasync->poll = poll; list_move(&fasync->list, &snd_fasync_list); @@ -163,8 +165,10 @@ void snd_fasync_free(struct snd_fasync *fasync) if (!fasync) return; - scoped_guard(spinlock_irq, &snd_fasync_lock) + scoped_guard(spinlock_irq, &snd_fasync_lock) { + fasync->on = 0; list_del_init(&fasync->list); + } flush_work(&snd_fasync_work); kfree(fasync); -- 2.53.0