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

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

[Colin Ian King]

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@gmail.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

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

[Michael Ellerman]

On Thu, 08 Jun 2023 10:58:49 +0100, Colin Ian King wrote:
> 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;
>            ^
> 
> [...]

Applied to powerpc/next.

[1/1] powerpc/powernv/sriov: perform null check on iov before dereferencing iov
      https://git.kernel.org/powerpc/c/f4f913c980bc6abe0ccfe88fe3909c125afe4a2d

cheers