From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:51759 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752472AbcGYA3o (ORCPT ); Sun, 24 Jul 2016 20:29:44 -0400 Subject: Patch "ALSA: timer: Fix negative queue usage by racy accesses" has been added to the 4.4-stable tree To: tiwai@suse.de, gregkh@linuxfoundation.org Cc: , From: Date: Sun, 24 Jul 2016 17:29:59 -0700 Message-ID: <1469406599102255@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled ALSA: timer: Fix negative queue usage by racy accesses to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: alsa-timer-fix-negative-queue-usage-by-racy-accesses.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 3fa6993fef634e05d200d141a85df0b044572364 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Mon, 4 Jul 2016 14:02:15 +0200 Subject: ALSA: timer: Fix negative queue usage by racy accesses From: Takashi Iwai commit 3fa6993fef634e05d200d141a85df0b044572364 upstream. The user timer tu->qused counter may go to a negative value when multiple concurrent reads are performed since both the check and the decrement of tu->qused are done in two individual locked contexts. This results in bogus read outs, and the endless loop in the user-space side. The fix is to move the decrement of the tu->qused counter into the same spinlock context as the zero-check of the counter. Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -1961,6 +1961,7 @@ static ssize_t snd_timer_user_read(struc qhead = tu->qhead++; tu->qhead %= tu->queue_size; + tu->qused--; spin_unlock_irq(&tu->qlock); if (tu->tread) { @@ -1974,7 +1975,6 @@ static ssize_t snd_timer_user_read(struc } spin_lock_irq(&tu->qlock); - tu->qused--; if (err < 0) goto _error; result += unit; Patches currently in stable-queue which might be from tiwai@suse.de are queue-4.4/alsa-hda-fix-the-headset-mic-jack-detection-on-dell-machine.patch queue-4.4/alsa-ctl-stop-notification-after-disconnection.patch queue-4.4/alsa-dummy-fix-a-use-after-free-at-closing.patch queue-4.4/alsa-timer-fix-negative-queue-usage-by-racy-accesses.patch queue-4.4/alsa-hda-fix-use-after-free-after-module-unload.patch queue-4.4/alsa-hda-realtek-add-new-pin-definition-in-alc225-pin-quirk-table.patch queue-4.4/alsa-hda-add-pci-id-for-kabylake-h.patch queue-4.4/alsa-pcm-free-chmap-at-pcm-free-callback-too.patch queue-4.4/alsa-au88x0-fix-calculation-in-vortex_wtdma_bufshift.patch queue-4.4/alsa-hda-realtek-add-lenovo-l460-to-docking-unit-fixup.patch queue-4.4/alsa-echoaudio-fix-memory-allocation.patch queue-4.4/alsa-hda-realtek-add-two-more-thinkpad-ids-5050-5053-for-tpt460-fixup.patch queue-4.4/alsa-hda-fix-read-before-array-start.patch queue-4.4/alsa-hda-add-amd-stoney-pci-id-with-proper-driver-caps.patch