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 8E4DB3C819C; Fri, 15 May 2026 16:14:25 +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=1778861665; cv=none; b=HZTfZ4+y9Sz04H+GBOc+2xCEWHx5w++XeB587NvQZ81FR7QOw54Ak+0H/bQlHgbfCjQP4zVWhi1o/2Fhn+AVolS8dNsM3fzpdOC/HZ2oREFT6b94FvAVSQ5SaO+1gIcOVvqj7smMDPNDCUoQNTTeItfy8L1ljUCDVS0kxUYKMWE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778861665; c=relaxed/simple; bh=kaz096cAwTW/dpLd/D6M4VtZmWQFpL0dyZ5B5kriTUE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ASglHG5r8yQAcGDFg4vdoV1kPSgvlGSm8nE+FYqAyKLFfRSb5sHZ6WWD854mFuGlCHavEii9uN/VgUYFfMbtkSfmMmJgOrDTORhXfqEWCXb4NbSGb0OWncG+CX8MDfv1HncNrTqDSMeWUpr1Kunc3eex40m7f2gYY/5GnZBDB7s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=llHMiVPU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="llHMiVPU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 26CEEC2BCB0; Fri, 15 May 2026 16:14:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778861665; bh=kaz096cAwTW/dpLd/D6M4VtZmWQFpL0dyZ5B5kriTUE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=llHMiVPUxD0RI3B9F6q+g9eRek5swUstlQ5kKU8pjI8cObz+Y5XRifgNUTnvQKD4H TXcIjWG2pA2v+BOJG69LTubjr0qkURhkRvlMjaRa/wYOPN0DPDtWZeL8efX04ODSzt rLj4gbettAzOXRQ/bKBXANHCvPlE/E7QE5u0vQSs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?C=C3=A1ssio=20Gabriel?= , Takashi Iwai , Sasha Levin Subject: [PATCH 6.6 415/474] ALSA: core: Serialize deferred fasync state checks Date: Fri, 15 May 2026 17:48:44 +0200 Message-ID: <20260515154724.039062055@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260515154715.053014143@linuxfoundation.org> References: <20260515154715.053014143@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Greg Kroah-Hartman --- sound/core/misc.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/sound/core/misc.c +++ b/sound/core/misc.c @@ -219,9 +219,11 @@ 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); @@ -234,8 +236,10 @@ void snd_fasync_free(struct snd_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);