linux-kernel - Re: [PATCH v3 0/2] pci: endpoint: Fix double free in pci_epf

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Message-ID: <20180227102030.GB26238@e107981-ln.cambridge.arm.com>
Date:   Tue, 27 Feb 2018 10:20:30 +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 v3 0/2] pci: endpoint: Fix double free in pci_epf_create()

On Tue, Feb 27, 2018 at 11:02:28AM +0100, Rolf Evers-Fischer wrote:
> This is version 3 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.
> 
> 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 (2):
>   pci: endpoint: Simplify name allocation for epf device
>   pci: endpoint: Fix kernel panic after put_device()
    ^^^

s/pci/PCI

Bjorn pointed that out too, I can do it when merging the patches myself
just a hint in case you have to respin it again, no problem.

Thanks,
Lorenzo

>  drivers/pci/endpoint/pci-epf-core.c | 24 +++++-------------------
>  1 file changed, 5 insertions(+), 19 deletions(-)
> 
> -- 
> 2.16.2
>