linux-kernel - Re: [PATCH v3] misc: alcor_pci: fix null-ptr-deref when there is no PCI bridge

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Date:   Wed, 19 May 2021 13:20:24 -0700
From:   Tong Zhang <ztong0001@...il.com>
To:     Dan Carpenter <dan.carpenter@...cle.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Arnd Bergmann <arnd@...db.de>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] misc: alcor_pci: fix null-ptr-deref when there is no
 PCI bridge

On Wed, May 19, 2021 at 1:40 AM Dan Carpenter <dan.carpenter@...cle.com> wrote:
>
> Hello Tong Zhang,
>
> This is a semi-automatic email about new static checker warnings.
>
> The patch 3ce3e45cc333: "misc: alcor_pci: fix null-ptr-deref when
> there is no PCI bridge" from May 13, 2021, leads to the following
> Smatch complaint:
>
>     drivers/misc/cardreader/alcor_pci.c:149 alcor_pci_init_check_aspm()
>     error: we previously assumed 'priv->parent_pdev' could be null (see line 147)
>
> drivers/misc/cardreader/alcor_pci.c
>    142          /*
>    143           * A device might be attached to root complex directly and
>    144           * priv->parent_pdev will be NULL. In this case we don't check its
>    145           * capability and disable ASPM completely.
>    146           */
>    147          if (!priv->parent_pdev)
>                     ^^^^^^^^^^^^^^^^^^
>
>    148                  priv->parent_cap_off = alcor_pci_find_cap_offset(priv,
>    149                                                           priv->parent_pdev);
>                                                                  ^^^^^^^^^^^^^^^^^^
> It will just crash inside the function call.  Is the if statement
> reversed?
>
>    150
>    151          if ((priv->pdev_cap_off == 0) || (priv->parent_cap_off == 0)) {
>
> regards,
> dan carpenter


Thanks Dan.
I already corrected this in v4
https://lkml.org/lkml/2021/5/18/1040
Please check if the issue persists.
- Tong