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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,
        Samuel Iglesias Gonsalvez <siglesias@igalia.com>,
        Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Subject: [PATCH 4.9 171/245] ipack/carriers/tpci200: Fix a double free in tpci200_pci_probe
Date:   Mon, 19 Jul 2021 16:51:53 +0200
Message-Id: <20210719144945.929352762@linuxfoundation.org>
In-Reply-To: <20210719144940.288257948@linuxfoundation.org>
References: <20210719144940.288257948@linuxfoundation.org>
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From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>

commit 9272e5d0028d45a3b45b58c9255e6e0df53f7ad9 upstream.

In the out_err_bus_register error branch of tpci200_pci_probe,
tpci200->info->cfg_regs is freed by tpci200_uninstall()->
tpci200_unregister()->pci_iounmap(..,tpci200->info->cfg_regs)
in the first time.

But later, iounmap() is called to free tpci200->info->cfg_regs
again.

My patch sets tpci200->info->cfg_regs to NULL after tpci200_uninstall()
to avoid the double free.

Fixes: cea2f7cdff2af ("Staging: ipack/bridges/tpci200: Use the TPCI200 in big endian mode")
Cc: stable <stable@vger.kernel.org>
Acked-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Link: https://lore.kernel.org/r/20210524093205.8333-1-lyl2019@mail.ustc.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/ipack/carriers/tpci200.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/ipack/carriers/tpci200.c
+++ b/drivers/ipack/carriers/tpci200.c
@@ -591,8 +591,11 @@ static int tpci200_pci_probe(struct pci_
 
 out_err_bus_register:
 	tpci200_uninstall(tpci200);
+	/* tpci200->info->cfg_regs is unmapped in tpci200_uninstall */
+	tpci200->info->cfg_regs = NULL;
 out_err_install:
-	iounmap(tpci200->info->cfg_regs);
+	if (tpci200->info->cfg_regs)
+		iounmap(tpci200->info->cfg_regs);
 out_err_ioremap:
 	pci_release_region(pdev, TPCI200_CFG_MEM_BAR);
 out_err_pci_request: