Re: [PATCH v4 3/8] PCI/DPC: Initialize info->id in dpc_process_error()

From: Naveen Naidu <naveennaidu479@gmail.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	oohall@gmail.com, bhelgaas@google.com,
	linuxppc-dev@lists.ozlabs.org,
	linux-kernel-mentees@lists.linuxfoundation.org
Subject: Re: [PATCH v4 3/8] PCI/DPC: Initialize info->id in dpc_process_error()
Date: Thu, 21 Oct 2021 22:01:28 +0530	[thread overview]
Message-ID: <20211021163128.rud3fv3jtnbi3ifp@theprophet> (raw)
In-Reply-To: <20211021012800.GA2656128@bhelgaas>

On 20/10, Bjorn Helgaas wrote:
> On Tue, Oct 05, 2021 at 10:48:10PM +0530, Naveen Naidu wrote:
> > In the dpc_process_error() path, info->id isn't initialized before being
> > passed to aer_print_error(). In the corresponding AER path, it is
> > initialized in aer_isr_one_error().
> > 
> > The error message shown during Coverity Scan is:
> > 
> >   Coverity #1461602
> >   CID 1461602 (#1 of 1): Uninitialized scalar variable (UNINIT)
> >   8. uninit_use_in_call: Using uninitialized value info.id when calling aer_print_error.
> > 
> > Initialize the "info->id" before passing it to aer_print_error()
> > 
> > Fixes: 8aefa9b0d910 ("PCI/DPC: Print AER status in DPC event handling")
> > Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
> > ---
> >  drivers/pci/pcie/dpc.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
> > index c556e7beafe3..df3f3a10f8bc 100644
> > --- a/drivers/pci/pcie/dpc.c
> > +++ b/drivers/pci/pcie/dpc.c
> > @@ -262,14 +262,14 @@ static int dpc_get_aer_uncorrect_severity(struct pci_dev *dev,
> >  
> >  void dpc_process_error(struct pci_dev *pdev)
> >  {
> > -	u16 cap = pdev->dpc_cap, status, source, reason, ext_reason;
> > +	u16 cap = pdev->dpc_cap, status, reason, ext_reason;
> >  	struct aer_err_info info;
> >  
> >  	pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &status);
> > -	pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &source);
> > +	pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &info.id);
> >  
> >  	pci_info(pdev, "containment event, status:%#06x source:%#06x\n",
> > -		 status, source);
> > +		 status, info.id);
> >  
> >  	reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN) >> 1;
> 
> Per PCIe r5.0, sec 7.9.15.5, the Source ID is defined only when the
> Trigger Reason indicates ERR_NONFATAL or ERR_FATAL.  So I think we
> need to extract this reason before reading PCI_EXP_DPC_SOURCE_ID,
> e.g.,
> 
>   reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN) >> 1;
>   if (reason == 1 || reason == 2)
>     pci_read_config_word(pdev, cap + PCI_EXP_DPC_SOURCE_ID, &info.id);
>   else
>     info.id = 0;
>

Thank you for the review, I'll make this change when I send a v5 for the
patch series.

> >  	ext_reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN_EXT) >> 5;
> > -- 
> > 2.25.1
> > 
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