This is a note to let you know that I've just added the patch titled ALSA: seq: Fix race at closing in virmidi driver 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-seq-fix-race-at-closing-in-virmidi-driver.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 <stable@xxxxxxxxxxxxxxx> know about it. >From 2d1b5c08366acd46c35a2e9aba5d650cb5bf5c19 Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai@xxxxxxx> Date: Mon, 1 Feb 2016 12:06:42 +0100 Subject: ALSA: seq: Fix race at closing in virmidi driver From: Takashi Iwai <tiwai@xxxxxxx> commit 2d1b5c08366acd46c35a2e9aba5d650cb5bf5c19 upstream. The virmidi driver has an open race at closing its assigned rawmidi device, and this may lead to use-after-free in snd_seq_deliver_single_event(). Plug the hole by properly protecting the linked list deletion and calling in the right order in snd_virmidi_input_close(). BugLink: http://lkml.kernel.org/r/CACT4Y+Zd66+w12fNN85-425cVQT=K23kWbhnCEcMB8s3us-Frw@xxxxxxxxxxxxxx Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Tested-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- sound/core/seq/seq_virmidi.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/sound/core/seq/seq_virmidi.c +++ b/sound/core/seq/seq_virmidi.c @@ -261,9 +261,13 @@ static int snd_virmidi_output_open(struc */ static int snd_virmidi_input_close(struct snd_rawmidi_substream *substream) { + struct snd_virmidi_dev *rdev = substream->rmidi->private_data; struct snd_virmidi *vmidi = substream->runtime->private_data; - snd_midi_event_free(vmidi->parser); + + write_lock_irq(&rdev->filelist_lock); list_del(&vmidi->list); + write_unlock_irq(&rdev->filelist_lock); + snd_midi_event_free(vmidi->parser); substream->runtime->private_data = NULL; kfree(vmidi); return 0; Patches currently in stable-queue which might be from tiwai@xxxxxxx are queue-4.4/alsa-seq-fix-race-at-closing-in-virmidi-driver.patch queue-4.4/alsa-hda-fix-bad-dereference-of-jack-object.patch queue-4.4/alsa-usb-audio-add-quirk-for-microsoft-lifecam-hd-6000.patch queue-4.4/alsa-rawmidi-remove-kernel-warning-for-null-user-space-buffer-check.patch queue-4.4/alsa-usb-audio-fix-oppo-ha-1-vendor-id.patch queue-4.4/alsa-timer-fix-race-at-concurrent-reads.patch queue-4.4/alsa-hda-realtek-support-dell-headset-mode-for-alc225.patch queue-4.4/alsa-hda-fix-static-checker-warning-in-patch_hdmi.c.patch queue-4.4/alsa-seq-fix-lockdep-warnings-due-to-double-mutex-locks.patch queue-4.4/alsa-usb-audio-fix-teac-ud-501-ud-503-nt-503-usb-delay.patch queue-4.4/alsa-timer-fix-wrong-instance-passed-to-slave-callbacks.patch queue-4.4/alsa-hda-disable-dynamic-clock-gating-on-broxton-before-reset.patch queue-4.4/alsa-hda-realtek-support-headset-mode-for-alc225.patch queue-4.4/alsa-hda-implement-loopback-control-switch-for-realtek-and-other-codecs.patch queue-4.4/alsa-hda-realtek-new-codec-support-of-alc225.patch queue-4.4/alsa-seq-degrade-the-error-message-for-too-many-opens.patch queue-4.4/alsa-compress-disable-get_codec_caps-ioctl-for-some-architectures.patch queue-4.4/alsa-rawmidi-make-snd_rawmidi_transmit-race-free.patch queue-4.4/alsa-hda-fix-speaker-output-from-vaio-aio-machines.patch queue-4.4/alsa-bebob-use-a-signed-return-type-for-get_formation_index.patch queue-4.4/alsa-add-missing-dependency-on-config_snd_timer.patch queue-4.4/alsa-dummy-implement-timer-backend-switching-more-safely.patch queue-4.4/alsa-dummy-disable-switching-timer-backend-via-sysfs.patch queue-4.4/alsa-seq-fix-incorrect-sanity-check-at-snd_seq_oss_synth_cleanup.patch queue-4.4/alsa-seq-fix-yet-another-races-among-alsa-timer-accesses.patch queue-4.4/alsa-usb-audio-avoid-freeing-umidi-object-twice.patch queue-4.4/revert-alsa-hda-fix-noise-on-gigabyte-z170x-mobo.patch queue-4.4/alsa-hda-add-fixup-for-mac-mini-7-1-model.patch queue-4.4/alsa-usb-audio-add-native-dsd-support-for-ps-audio-nuwave-dac.patch queue-4.4/alsa-timer-fix-leftover-link-at-closing.patch queue-4.4/alsa-rawmidi-fix-race-at-copying-updating-the-position.patch queue-4.4/alsa-pcm-fix-potential-deadlock-in-oss-emulation.patch queue-4.4/alsa-timer-fix-link-corruption-due-to-double-start-or-stop.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html