From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx48mql4D5E9JcFzHdUHYjqoHTGE1m7i+FGr59iGjF7sgXbROGWZukUFNwUTdlkZRa/k8IhLr ARC-Seal: i=1; a=rsa-sha256; t=1524406871; cv=none; d=google.com; s=arc-20160816; b=L+F8FadG9t9K7526Pq5dL1wMAyUzAKlnnB23s8QfucfgKA7CH4deWgP/c/e71m2fuj DqXItGiGwYW9rrVGzy1mpynZeHTHo+LlW9C8qP2x88wtsm0otnKc4mtQoGddCYiLBvSk ik4f+r564hH9yFYcH0YC92RaE0crU+cYrLpMRlxbpEChKP8ffzlnT89EhWOgj+kDplp9 u5zDAhcLO81+4Z4rP99nNBmoM1nnEG+kb2tHgnkLNgQyd1r8RoWTlrY2irhYz8jo6AbB PBS0mRBGaAqpxAj1+6fgmTRgXlus1V0UC3jF+UeHqla6HcMvT6LAMJeG10oMJ8r5Mdoj 3SwA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=h+sW0A36Aqwk5zab9UGY8Y7nBa/eRUCLa2uKHXu42Fc=; b=P0TWQaNvgDeRrHruuCTtEP2aNRcG99u1Gs5Ow4UF7PTYS5X6NlESamgeN4EHXfo8EC mazOeOb1F3VtA45omTqlKQHzePAzRwlNpZICM+WIL6qEX8xXRK/3Pek8u36nvZMJap6G U1bIsuEX+njhqyWEwg8eg/vgZyS6HJlIIO9qeIH/mdZCfqejD3Eem0X1QSmgoe/WmazM +2G/grx3U9t4CmoTnIgwDk2F3IQQOdH5VXkIVTeyunn8pCanO+KBdwEAH5yUuIBscrv6 VvzN8jot3rRO+o5Nj5XwZ/Rj5qLqYxp1jfvOJXhvoBUhVd0xnHYNCb6tVshv0NLB5KhP pZ+w== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter , Takashi Iwai Subject: [PATCH 3.18 35/52] ALSA: pcm: Fix mutex unbalance in OSS emulation ioctls Date: Sun, 22 Apr 2018 15:54:08 +0200 Message-Id: <20180422135317.044121415@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180422135315.254787616@linuxfoundation.org> References: <20180422135315.254787616@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1598455080797885449?= X-GMAIL-MSGID: =?utf-8?q?1598456459633112188?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit f6d297df4dd47ef949540e4a201230d0c5308325 upstream. The previous fix 40cab6e88cb0 ("ALSA: pcm: Return -EBUSY for OSS ioctls changing busy streams") introduced some mutex unbalance; the check of runtime->oss.rw_ref was inserted in a wrong place after the mutex lock. This patch fixes the inconsistency by rewriting with the helper functions to lock/unlock parameters with the stream check. Fixes: 40cab6e88cb0 ("ALSA: pcm: Return -EBUSY for OSS ioctls changing busy streams") Reported-by: Dan Carpenter Cc: Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/oss/pcm_oss.c | 67 +++++++++++++++++++++++++++++------------------ 1 file changed, 42 insertions(+), 25 deletions(-) --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -833,6 +833,23 @@ static int choose_rate(struct snd_pcm_su return snd_pcm_hw_param_near(substream, params, SNDRV_PCM_HW_PARAM_RATE, best_rate, NULL); } +/* parameter locking: returns immediately if tried during streaming */ +static int lock_params(struct snd_pcm_runtime *runtime) +{ + if (mutex_lock_interruptible(&runtime->oss.params_lock)) + return -ERESTARTSYS; + if (atomic_read(&runtime->oss.rw_ref)) { + mutex_unlock(&runtime->oss.params_lock); + return -EBUSY; + } + return 0; +} + +static void unlock_params(struct snd_pcm_runtime *runtime) +{ + mutex_unlock(&runtime->oss.params_lock); +} + /* call with params_lock held */ static int snd_pcm_oss_change_params_locked(struct snd_pcm_substream *substream) { @@ -1773,6 +1790,8 @@ static int snd_pcm_oss_set_rate(struct s for (idx = 1; idx >= 0; --idx) { struct snd_pcm_substream *substream = pcm_oss_file->streams[idx]; struct snd_pcm_runtime *runtime; + int err; + if (substream == NULL) continue; runtime = substream->runtime; @@ -1780,15 +1799,14 @@ static int snd_pcm_oss_set_rate(struct s rate = 1000; else if (rate > 192000) rate = 192000; - if (mutex_lock_interruptible(&runtime->oss.params_lock)) - return -ERESTARTSYS; - if (atomic_read(&runtime->oss.rw_ref)) - return -EBUSY; + err = lock_params(runtime); + if (err < 0) + return err; if (runtime->oss.rate != rate) { runtime->oss.params = 1; runtime->oss.rate = rate; } - mutex_unlock(&runtime->oss.params_lock); + unlock_params(runtime); } return snd_pcm_oss_get_rate(pcm_oss_file); } @@ -1813,18 +1831,19 @@ static int snd_pcm_oss_set_channels(stru for (idx = 1; idx >= 0; --idx) { struct snd_pcm_substream *substream = pcm_oss_file->streams[idx]; struct snd_pcm_runtime *runtime; + int err; + if (substream == NULL) continue; runtime = substream->runtime; - if (mutex_lock_interruptible(&runtime->oss.params_lock)) - return -ERESTARTSYS; - if (atomic_read(&runtime->oss.rw_ref)) - return -EBUSY; + err = lock_params(runtime); + if (err < 0) + return err; if (runtime->oss.channels != channels) { runtime->oss.params = 1; runtime->oss.channels = channels; } - mutex_unlock(&runtime->oss.params_lock); + unlock_params(runtime); } return snd_pcm_oss_get_channels(pcm_oss_file); } @@ -1897,6 +1916,7 @@ static int snd_pcm_oss_get_formats(struc static int snd_pcm_oss_set_format(struct snd_pcm_oss_file *pcm_oss_file, int format) { int formats, idx; + int err; if (format != AFMT_QUERY) { formats = snd_pcm_oss_get_formats(pcm_oss_file); @@ -1910,15 +1930,14 @@ static int snd_pcm_oss_set_format(struct if (substream == NULL) continue; runtime = substream->runtime; - if (atomic_read(&runtime->oss.rw_ref)) - return -EBUSY; - if (mutex_lock_interruptible(&runtime->oss.params_lock)) - return -ERESTARTSYS; + err = lock_params(runtime); + if (err < 0) + return err; if (runtime->oss.format != format) { runtime->oss.params = 1; runtime->oss.format = format; } - mutex_unlock(&runtime->oss.params_lock); + unlock_params(runtime); } } return snd_pcm_oss_get_format(pcm_oss_file); @@ -1966,12 +1985,11 @@ static int snd_pcm_oss_set_subdivide(str if (substream == NULL) continue; runtime = substream->runtime; - if (atomic_read(&runtime->oss.rw_ref)) - return -EBUSY; - if (mutex_lock_interruptible(&runtime->oss.params_lock)) - return -ERESTARTSYS; + err = lock_params(runtime); + if (err < 0) + return err; err = snd_pcm_oss_set_subdivide1(substream, subdivide); - mutex_unlock(&runtime->oss.params_lock); + unlock_params(runtime); if (err < 0) return err; } @@ -2006,12 +2024,11 @@ static int snd_pcm_oss_set_fragment(stru if (substream == NULL) continue; runtime = substream->runtime; - if (atomic_read(&runtime->oss.rw_ref)) - return -EBUSY; - if (mutex_lock_interruptible(&runtime->oss.params_lock)) - return -ERESTARTSYS; + err = lock_params(runtime); + if (err < 0) + return err; err = snd_pcm_oss_set_fragment1(substream, val); - mutex_unlock(&runtime->oss.params_lock); + unlock_params(runtime); if (err < 0) return err; }