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Date:   Wed, 13 Dec 2023 17:14:37 +0000
From:   Simon Horman <horms@kernel.org>
To:     Przemek Kitszel <przemyslaw.kitszel@intel.com>
Cc:     Kunwu Chan <chentao@kylinos.cn>, jesse.brandeburg@intel.com,
        anthony.l.nguyen@intel.com, davem@davemloft.net,
        edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
        richardcochran@gmail.com, jacob.e.keller@intel.com,
        karol.kolacinski@intel.com, michal.michalik@intel.com,
        intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Kunwu Chan <kunwu.chan@hotmail.com>
Subject: Re: [PATCH v2 iwl-next] ice: Fix some null pointer dereference
 issues in ice_ptp.c
Message-ID: <20231213171437.GI5817@kernel.org>
References: <20231212024015.11595-1-chentao@kylinos.cn>
 <1abd6bcb-6f6c-10a7-9b6f-e5e038233af8@intel.com>
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On Wed, Dec 13, 2023 at 10:49:10AM +0100, Przemek Kitszel wrote:
> On 12/12/23 03:40, Kunwu Chan wrote:
> > devm_kasprintf() returns a pointer to dynamically allocated memory
> > which can be NULL upon failure.
> > 
> > Fixes: d938a8cca88a ("ice: Auxbus devices & driver for E822 TS")
> > Cc: Kunwu Chan <kunwu.chan@hotmail.com>
> > Suggested-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
> 
> You found the bug (or some some static analysis tool in that case);
> there is no need to add Suggested-by for every person that suggests
> something during review - the tag is for "person/s that suggested
> making such change in the repo".
> 
> Subject line would be better if less generic, eg:
> ice: avoid null deref of ptp auxbus name
> 
> > Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
> > ---
> >   drivers/net/ethernet/intel/ice/ice_ptp.c | 4 ++++
> >   1 file changed, 4 insertions(+)
> > 
> > diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c
> > index e9e59f4b5580..848e3e063e64 100644
> > --- a/drivers/net/ethernet/intel/ice/ice_ptp.c
> > +++ b/drivers/net/ethernet/intel/ice/ice_ptp.c
> > @@ -2743,6 +2743,8 @@ static int ice_ptp_register_auxbus_driver(struct ice_pf *pf)
> >   	name = devm_kasprintf(dev, GFP_KERNEL, "ptp_aux_dev_%u_%u_clk%u",
> >   			      pf->pdev->bus->number, PCI_SLOT(pf->pdev->devfn),
> >   			      ice_get_ptp_src_clock_index(&pf->hw));
> > +	if (!name)
> > +		return -ENOMEM;
> >   	aux_driver->name = name;
> >   	aux_driver->shutdown = ice_ptp_auxbus_shutdown;
> > @@ -2989,6 +2991,8 @@ static int ice_ptp_create_auxbus_device(struct ice_pf *pf)
> >   	name = devm_kasprintf(dev, GFP_KERNEL, "ptp_aux_dev_%u_%u_clk%u",
> >   			      pf->pdev->bus->number, PCI_SLOT(pf->pdev->devfn),
> >   			      ice_get_ptp_src_clock_index(&pf->hw));
> > +	if (!name)
> > +		return -ENOMEM;
> >   	aux_dev->name = name;
> >   	aux_dev->id = id;
> 
> Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
> 
> Regarding iwl-next vs iwl-net: this bug is really unlikely to manifest,
> as we take care of both earlier and future mem allocs for ptp auxbus,
> and auxiliary_device_init() checks for null name, so no big deal,
> so: -next is fine

Thanks. FWIIW, this looks good to me too.

Reviewed-by: Simon Horman <horms@kernel.org>