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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Kunihiko Hayashi <hayashi.kunihiko@socionext.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Sasha Levin <sashal@kernel.org>, linux-pci@vger.kernel.org
Subject: [PATCH AUTOSEL 5.7 028/388] PCI: endpoint: functions/pci-epf-test: Fix DMA channel release
Date:   Wed, 17 Jun 2020 21:02:05 -0400
Message-Id: <20200618010805.600873-28-sashal@kernel.org>
In-Reply-To: <20200618010805.600873-1-sashal@kernel.org>
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From: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>

[ Upstream commit 0e86d981f9b7252e9716c5137cd8e4d9ad8ef32f ]

When unbinding pci_epf_test, pci_epf_test_clean_dma_chan() is called in
pci_epf_test_unbind() even though epf_test->dma_supported is false.

As a result, dma_release_channel() will trigger a NULL pointer
dereference because dma_chan is not set.

Avoid calling dma_release_channel() if epf_test->dma_supported
is false.

Link: https://lore.kernel.org/r/1587540287-10458-1-git-send-email-hayashi.kunihiko@socionext.com
Fixes: 5ebf3fc59bd2 ("PCI: endpoint: functions/pci-epf-test: Add DMA support to transfer data")
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
[lorenzo.pieralisi@arm.com: commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pci/endpoint/functions/pci-epf-test.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 60330f3e3751..c89a9561439f 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -187,6 +187,9 @@ static int pci_epf_test_init_dma_chan(struct pci_epf_test *epf_test)
  */
 static void pci_epf_test_clean_dma_chan(struct pci_epf_test *epf_test)
 {
+	if (!epf_test->dma_supported)
+		return;
+
 	dma_release_channel(epf_test->dma_chan);
 	epf_test->dma_chan = NULL;
 }
-- 
2.25.1