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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 091/247] media: cx25821: Fix a bug when reallocating some dma memory
Date:   Mon,  1 Mar 2021 17:11:51 +0100
Message-Id: <20210301161036.130673934@linuxfoundation.org>
In-Reply-To: <20210301161031.684018251@linuxfoundation.org>
References: <20210301161031.684018251@linuxfoundation.org>
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From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>

[ Upstream commit b2de3643c5024fc4fd128ba7767c7fb8b714bea7 ]

This function looks like a realloc.

However, if 'risc->cpu != NULL', the memory will be freed, but never
reallocated with the bigger 'size'.
Explicitly set 'risc->cpu' to NULL, so that the reallocation is
correctly performed a few lines below.

[hverkuil: NULL != risc->cpu -> risc->cpu]

Fixes: 5ede94c70553 ("[media] cx25821: remove bogus btcx_risc dependency)
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/media/pci/cx25821/cx25821-core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/pci/cx25821/cx25821-core.c b/drivers/media/pci/cx25821/cx25821-core.c
index 2f0171134f7e1..e04fe9f17b7aa 100644
--- a/drivers/media/pci/cx25821/cx25821-core.c
+++ b/drivers/media/pci/cx25821/cx25821-core.c
@@ -986,8 +986,10 @@ int cx25821_riscmem_alloc(struct pci_dev *pci,
 	__le32 *cpu;
 	dma_addr_t dma = 0;
 
-	if (NULL != risc->cpu && risc->size < size)
+	if (risc->cpu && risc->size < size) {
 		pci_free_consistent(pci, risc->size, risc->cpu, risc->dma);
+		risc->cpu = NULL;
+	}
 	if (NULL == risc->cpu) {
 		cpu = pci_zalloc_consistent(pci, size, &dma);
 		if (NULL == cpu)
-- 
2.27.0