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From:   Lv Yunlong <lyl2019@mail.ustc.edu.cn>
To:     selvin.xavier@broadcom.com, devesh.sharma@broadcom.com,
        somnath.kotur@broadcom.com, sriharsha.basavapatna@broadcom.com,
        nareshkumar.pbs@broadcom.com, dledford@redhat.com, jgg@ziepe.ca
Cc:     linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
        Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Subject: [PATCH] RDMA/bnxt_re/qplib_res: Fix a double free in bnxt_qplib_alloc_res
Date:   Mon, 26 Apr 2021 07:06:14 -0700
Message-Id: <20210426140614.6722-1-lyl2019@mail.ustc.edu.cn>
MIME-Version: 1.0
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In bnxt_qplib_alloc_res, it calls bnxt_qplib_alloc_dpi_tbl().
Inside bnxt_qplib_alloc_dpi_tbl, dpit->dbr_bar_reg_iomem is freed via
pci_iounmap() in unmap_io error branch. After the callee returns err code,
bnxt_qplib_alloc_res calls bnxt_qplib_free_res()->bnxt_qplib_free_dpi_tbl()
in fail branch. Then dpit->dbr_bar_reg_iomem is freed in the second time by
pci_iounmap().

My patch set dpit->dbr_bar_reg_iomem to NULL after it is freed by pci_iounmap()
in the first time, to avoid the double free.

Fixes: 1ac5a40479752 ("RDMA/bnxt_re: Add bnxt_re RoCE driver")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
---
 drivers/infiniband/hw/bnxt_re/qplib_res.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/infiniband/hw/bnxt_re/qplib_res.c b/drivers/infiniband/hw/bnxt_re/qplib_res.c
index fa7878336100..3ca47004b752 100644
--- a/drivers/infiniband/hw/bnxt_re/qplib_res.c
+++ b/drivers/infiniband/hw/bnxt_re/qplib_res.c
@@ -854,6 +854,7 @@ static int bnxt_qplib_alloc_dpi_tbl(struct bnxt_qplib_res     *res,
 
 unmap_io:
 	pci_iounmap(res->pdev, dpit->dbr_bar_reg_iomem);
+	dpit->dbr_bar_reg_iomem = NULL;
 	return -ENOMEM;
 }
 
-- 
2.25.1