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Tue, 14 Jul 2026 00:12:08 -0700 (PDT) Date: Tue, 14 Jul 2026 10:12:02 +0300 From: Dan Carpenter To: Alfie Varghese Cc: sakari.ailus@linux.intel.com, gregkh@linuxfoundation.org, bingbu.cao@intel.com, linux-media@vger.kernel.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH] staging: media: ipu7: add NULL checks before ipu7_mmu_cleanup() in remove Message-ID: References: <20260713172127.615-1-alfievarghese22@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260713172127.615-1-alfievarghese22@gmail.com> On Mon, Jul 13, 2026 at 10:51:27PM +0530, Alfie Varghese wrote: > ipu7_pci_remove() calls ipu7_mmu_cleanup() on isp->isys->mmu and > isp->psys->mmu without checking whether isys or psys are valid > pointers. If ipu7_pci_probe() partially failed and left isys or psys > as NULL or an error pointer, the remove path will dereference a bad > pointer and crash the kernel. > > The probe error cleanup path already guards these calls correctly with > IS_ERR_OR_NULL() checks. Apply the same guards in ipu7_pci_remove(). > > Signed-off-by: Alfie Varghese > --- > drivers/staging/media/ipu7/ipu7.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/staging/media/ipu7/ipu7.c b/drivers/staging/media/ipu7/ipu7.c > index 310e3f24e571..41436f22c684 100644 > --- a/drivers/staging/media/ipu7/ipu7.c > +++ b/drivers/staging/media/ipu7/ipu7.c > @@ -2637,8 +2637,10 @@ static void ipu7_pci_remove(struct pci_dev *pdev) > if (!IS_ERR_OR_NULL(isp->fw_code_region)) > vfree(isp->fw_code_region); > > - ipu7_mmu_cleanup(isp->isys->mmu); > - ipu7_mmu_cleanup(isp->psys->mmu); > + if (!IS_ERR_OR_NULL(isp->isys) && !IS_ERR_OR_NULL(isp->isys->mmu)) > + ipu7_mmu_cleanup(isp->isys->mmu); > + if (!IS_ERR_OR_NULL(isp->psys) && !IS_ERR_OR_NULL(isp->psys->mmu)) > + ipu7_mmu_cleanup(isp->psys->mmu); The original code here is fine. It is the probe() function which is is wrong. See my blog on how to fix the probe() function. https://staticthinking.wordpress.com/2022/04/28/free-the-last-thing-style/ regards, dan carpenter