linux-kernel - [PATCH][next] powerpc/powernv/sriov: perform null check on iov before dereferencing iov

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Message-Id: <20230608095849.1147969-1-colin.i.king@gmail.com>
Date:   Thu,  8 Jun 2023 10:58:49 +0100
From:   Colin Ian King <colin.i.king@...il.com>
To:     Michael Ellerman <mpe@...erman.id.au>,
        Nicholas Piggin <npiggin@...il.com>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Oliver O'Halloran <oohall@...il.com>,
        linuxppc-dev@...ts.ozlabs.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][next] powerpc/powernv/sriov: perform null check on iov before dereferencing iov

Currently pointer iov is being dereferenced before the null check of iov
which can lead to null pointer dereference errors. Fix this by moving the
iov null check before the dereferencing.

Detected using cppcheck static analysis:
linux/arch/powerpc/platforms/powernv/pci-sriov.c:597:12: warning: Either
the condition '!iov' is redundant or there is possible null pointer
dereference: iov. [nullPointerRedundantCheck]
 num_vfs = iov->num_vfs;
           ^

Fixes: 052da31d45fc ("powerpc/powernv/sriov: De-indent setup and teardown")
Signed-off-by: Colin Ian King <colin.i.king@...il.com>
---
 arch/powerpc/platforms/powernv/pci-sriov.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-sriov.c b/arch/powerpc/platforms/powernv/pci-sriov.c
index 7195133b26bb..42e1f045199f 100644
--- a/arch/powerpc/platforms/powernv/pci-sriov.c
+++ b/arch/powerpc/platforms/powernv/pci-sriov.c
@@ -594,11 +594,10 @@ static void pnv_pci_sriov_disable(struct pci_dev *pdev)
 	struct pnv_iov_data   *iov;
 
 	iov = pnv_iov_get(pdev);
-	num_vfs = iov->num_vfs;
-	base_pe = iov->vf_pe_arr[0].pe_number;
-
 	if (WARN_ON(!iov))
 		return;
+	num_vfs = iov->num_vfs;
+	base_pe = iov->vf_pe_arr[0].pe_number;
 
 	/* Release VF PEs */
 	pnv_ioda_release_vf_PE(pdev);
-- 
2.30.2