linux-kernel - Re: [PATCH v5 0/3] pci: endpoint: Fix double free in pci_epf

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Date:   Thu, 1 Mar 2018 12:22:55 +0000
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:     Rolf Evers-Fischer <embedded24@...rs-fischer.de>
Cc:     kishon@...com, bhelgaas@...gle.com, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org, andy.shevchenko@...il.com
Subject: Re: [PATCH v5 0/3] pci: endpoint: Fix double free in pci_epf_create()

On Wed, Feb 28, 2018 at 06:32:17PM +0100, Rolf Evers-Fischer wrote:
> This is version 5 of a patchset to avoid double free in function
> 'pci_epf_create()'.
> 
> When I accidentally created a new endpoint device with an empty name,
> the kernel warned about "attempted to be registered with empty name!"
> and crashed afterwards.
> 
> It turned out that the crash was not caused by the 'device_add()'
> function itself, but by a double kfree of 'epf->name' and 'epf'.
> 
> The first patch just simplifies the code, while the second patch
> fixes the problem. The third patch removes the goto labels.
> 
> Thank you Andy and Kishon for your Ack/Review on v3 for patches 1 and 2.
> In v4 of these patches only the first lines of the commit messages
> have been changed. In v5 these two patches have not been changed.
> Therefore the 'Acked-By'/'Reviewed-By' lines have been added. I hope
> that's acceptable.
> 
> Changes in v5:
> - Beautified the ugly part of Patch #3 (v4), where the correct return
>   value was hidden under two levels of 'if'.
> 
> Changes in v4:
> - s/pci/PCI and s/epf/EPF in the first line of
>   recent commit messages (thanks, Bjorn!)
> - The new patch #3 removes the goto labels
>   in function 'pci_epf_create()' (thanks, Lorenzo!)
> 
> Changes in v3:
> - Matched to other pending pci endpoint commits (thanks, Bjorn!)
> - Added "Fixes" tag in patch 2 (thanks, Andy!)
> 
> Changes in v2:
> - Based on feedback from Lorenzo, Andy and Kishon (thanks!)
> - Change IDs removed
> - First patch completely reworked in order to eliminate the
>   need for the second 'kstrdup' allocation and the 'kfree' of
>   the first allocation.
>   It was tested with name="pci_epf_test.0" and name="pci_epb":
>   The 'epf->name' was "pci_epf_test" or "pci_epb" (=unchanged).
> 
> Rolf Evers-Fischer (3):
>   PCI: endpoint: Simplify name allocation for EPF device
>   PCI: endpoint: Fix kernel panic after put_device()
>   PCI: endpoint: pci_epf_create: remove goto labels
> 
>  drivers/pci/endpoint/pci-epf-core.c | 52 +++++++++++--------------------------
>  1 file changed, 15 insertions(+), 37 deletions(-)

Applied to pci/endpoint for v4.17, thanks.

Lorenzo