Re: [dpdk-dev] [PATCH 1/2] baseband/fpga_5gnr_fec: fix segfaults with debug

["Chautru, Nicolas" <nicolas.chautru@intel.com>]

Hi Maxime, 

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Tuesday, October 6, 2020 9:34 AM
> To: Chautru, Nicolas <nicolas.chautru@intel.com>; dev@dpdk.org;
> stable@dpdk.org; trix@redhat.com
> Subject: Re: [PATCH 1/2] baseband/fpga_5gnr_fec: fix segfaults with debug
> 
> Hi Nicolas,
> 
> On 10/6/20 6:14 PM, Chautru, Nicolas wrote:
> > Thanks Maxime
> > I am not totally sure that this actually got broken in the very commit you
> point to (I think that there was another pci generic commit which changed
> the assumption when this pointer was set), but it doesn't harm to change
> anyway for stable build.
> > Note this is already like this in the new PMD acc100.
> 
> For fpga_5gnr_fec, we reproduced the issue with v20.05, which was the
> version the driver was introduced.
> 
> For fpga_lte_fec, it seems to be the same. The driver was in introduced in
> v19.08, and dev->device.driver was also assigned after driver's probe
> callback is called:
> 
> http://code.dpdk.org/dpdk/v19.08/source/drivers/bus/pci/pci_common.c#L
> 212

OK Thanks you are right. The change moving the driver assignment to end of probing was done in parallel prior to the formal upstreaming of these drivers. 

> 
> Thanks,
> Maxime
> 
> > Acked-By: Nicolas Chautru <nicolas.chautru@intel.com>
> >
> >> -----Original Message-----
> >> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> >> Sent: Tuesday, October 6, 2020 3:04 AM
> >> To: dev@dpdk.org; stable@dpdk.org; Chautru, Nicolas
> >> <nicolas.chautru@intel.com>; trix@redhat.com
> >> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> >> Subject: [PATCH 1/2] baseband/fpga_5gnr_fec: fix segfaults with debug
> >>
> >> When RTE_LIBRTE_BBDEV_DEBUG is enabled, rte_device's driver pointer
> >> is dereferenced twice in fpga_5gnr_fec's probe callback.
> >> It causes a segmentation fault because this pointer is only assigned
> >> after probe callback call.
> >>
> >> This patch makes use of rte_pci_driver pointer instead.
> >>
> >> Fixes: 0b5927cbcba7 ("baseband/fpga_5gnr_fec: add PMD for FPGA 5GNR
> >> FEC")
> >>
> >> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> >> ---
> >>  drivers/baseband/fpga_5gnr_fec/rte_fpga_5gnr_fec.c | 4 ++--
> >>  1 file changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/baseband/fpga_5gnr_fec/rte_fpga_5gnr_fec.c
> >> b/drivers/baseband/fpga_5gnr_fec/rte_fpga_5gnr_fec.c
> >> index 61f9c04ba2..11ee4d3e10 100644
> >> --- a/drivers/baseband/fpga_5gnr_fec/rte_fpga_5gnr_fec.c
> >> +++ b/drivers/baseband/fpga_5gnr_fec/rte_fpga_5gnr_fec.c
> >> @@ -1839,7 +1839,7 @@ fpga_5gnr_fec_init(struct rte_bbdev *dev,
> >> struct rte_pci_driver *drv)
> >>
> >>  	rte_bbdev_log_debug(
> >>  			"Init device %s [%s] @ virtaddr %p phyaddr
> %#"PRIx64,
> >> -			dev->device->driver->name, dev->data->name,
> >> +			drv->driver.name, dev->data->name,
> >>  			(void *)pci_dev->mem_resource[0].addr,
> >>  			pci_dev->mem_resource[0].phys_addr);
> >>  }
> >> @@ -1895,7 +1895,7 @@ fpga_5gnr_fec_probe(struct rte_pci_driver
> *pci_drv,
> >>  		((uint16_t)(version_id >> 16)), ((uint16_t)version_id));
> >>
> >>  #ifdef RTE_LIBRTE_BBDEV_DEBUG
> >> -	if (!strcmp(bbdev->device->driver->name,
> >> +	if (!strcmp(pci_drv->driver.name,
> >
> > Why do you have to change this one?
> >
> > Acked-by: Nicolas Chautru <nicolas.chautru@intel.com>
> >
> >>  			RTE_STR(FPGA_5GNR_FEC_PF_DRIVER_NAME)))
> >>  		print_static_reg_debug_info(d->mmio_base);
> >>  #endif
> >> --
> >> 2.26.2
> >