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[80.193.200.194]) by smtp.gmail.com with ESMTPSA id m41-20020a05600c3b2900b00393e6f6c130sm3653656wms.42.2022.04.24.13.59.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 24 Apr 2022 13:59:46 -0700 (PDT) From: Colin Ian King To: Takashi Iwai , alsa-devel@alsa-project.org Subject: [PATCH] ALSA: pcm: Check for null pointer of pointer substream before dereferencing it Date: Sun, 24 Apr 2022 21:59:45 +0100 Message-Id: <20220424205945.1372247-1-colin.i.king@gmail.com> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" Pointer substream is being dereferenced on the assignment of pointer card before substream is being null checked with the macro PCM_RUNTIME_CHECK. Although PCM_RUNTIME_CHECK calls BUG_ON, it still is useful to perform the the pointer check before card is assigned. Fixes: commit d4cfb30fce03 ("ALSA: pcm: Set per-card upper limit of PCM buffer allocations") Signed-off-by: Colin Ian King --- sound/core/pcm_memory.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c index 8848d2f3160d..b8296b6eb2c1 100644 --- a/sound/core/pcm_memory.c +++ b/sound/core/pcm_memory.c @@ -453,7 +453,6 @@ EXPORT_SYMBOL(snd_pcm_lib_malloc_pages); */ int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream) { - struct snd_card *card = substream->pcm->card; struct snd_pcm_runtime *runtime; if (PCM_RUNTIME_CHECK(substream)) @@ -462,6 +461,8 @@ int snd_pcm_lib_free_pages(struct snd_pcm_substream *substream) if (runtime->dma_area == NULL) return 0; if (runtime->dma_buffer_p != &substream->dma_buffer) { + struct snd_card *card = substream->pcm->card; + /* it's a newly allocated buffer. release it now. */ do_free_pages(card, runtime->dma_buffer_p); kfree(runtime->dma_buffer_p);