The patch ASoC: Fix use-after-free at card unregistration has been applied to the asoc tree at git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark >From 4efda5f2130da033aeedc5b3205569893b910de2 Mon Sep 17 00:00:00 2001 From: Takashi Iwai <tiwai@xxxxxxx> Date: Wed, 24 May 2017 10:19:45 +0200 Subject: [PATCH] ASoC: Fix use-after-free at card unregistration soc_cleanup_card_resources() call snd_card_free() at the last of its procedure. This turned out to lead to a use-after-free. PCM runtimes have been already removed via soc_remove_pcm_runtimes(), while it's dereferenced later in soc_pcm_free() called via snd_card_free(). The fix is simple: just move the snd_card_free() call to the beginning of the whole procedure. This also gives another benefit: it guarantees that all operations have been shut down before actually releasing the resources, which was racy until now. Reported-and-tested-by: Robert Jarzmik <robert.jarzmik@xxxxxxx> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> --- sound/soc/soc-core.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index aae099c0e502..754e3ef8d7ae 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -2286,6 +2286,9 @@ static int soc_cleanup_card_resources(struct snd_soc_card *card) list_for_each_entry(rtd, &card->rtd_list, list) flush_delayed_work(&rtd->delayed_work); + /* free the ALSA card at first; this syncs with pending operations */ + snd_card_free(card->snd_card); + /* remove and free each DAI */ soc_remove_dai_links(card); soc_remove_pcm_runtimes(card); @@ -2300,9 +2303,7 @@ static int soc_cleanup_card_resources(struct snd_soc_card *card) if (card->remove) card->remove(card); - snd_card_free(card->snd_card); return 0; - } /* removes a socdev */ -- 2.11.0