Messages in this thread | | | From | Sai Krishna Gajula <> | Subject | Re: [net PATCH v2] octeontx2-af: Move validation of ptp pointer before its usage | Date | Fri, 23 Jun 2023 11:28:19 +0000 |
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> -----Original Message----- > From: Dan Carpenter <dan.carpenter@linaro.org> > Sent: Friday, June 9, 2023 6:48 PM > To: Sai Krishna Gajula <saikrishnag@marvell.com> > Cc: davem@davemloft.net; edumazet@google.com; kuba@kernel.org; > pabeni@redhat.com; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; > Sunil Kovvuri Goutham <sgoutham@marvell.com>; > maciej.fijalkowski@intel.com; Naveen Mamindlapalli > <naveenm@marvell.com> > Subject: Re: [net PATCH v2] octeontx2-af: Move validation of ptp > pointer before its usage > > On Fri, Jun 09, 2023 at 05:28:06PM +0530, Sai Krishna wrote: > > @@ -428,7 +427,7 @@ static int ptp_probe(struct pci_dev *pdev, > > return 0; > > > > error_free: > > - devm_kfree(dev, ptp); > > + kfree(ptp); > > Yeah. It's strange any time we call devm_kfree()... So there is something > here which I have not understood. We moved from devm_kzalloc/devm_kfree to kzalloc/kfree as per review comments from Maciej. > > > > > error: > > /* For `ptp_get()` we need to differentiate between the case > > This probe function is super weird how it returns success on the failure path. > One concern, I had initially was that if anything returns -EPROBE_DEFER then > we cannot recover. That's not possible in the current code, but it makes me > itch... But here is a different crash. >
In few circumstances, the PTP device is probed before the AF device in the driver. In such instance, -EPROBE_DEFER is used. -- EDEFER_PROBE is useful when probe order changes. Ex: AF driver probes before PTP.
> drivers/net/ethernet/marvell/octeontx2/af/ptp.c > 432 error: > 433 /* For `ptp_get()` we need to differentiate between the case > 434 * when the core has not tried to probe this device and the case > when > 435 * the probe failed. In the later case we pretend that the > 436 * initialization was successful and keep the error in > 437 * `dev->driver_data`. > 438 */ > 439 pci_set_drvdata(pdev, ERR_PTR(err)); > 440 if (!first_ptp_block) > 441 first_ptp_block = ERR_PTR(err); > > first_ptp_block is NULL for unprobed, an error pointer for probe failure, or > valid pointer.
This is correct. > > 442 > 443 return 0; > 444 } > > drivers/net/ethernet/marvell/octeontx2/af/ptp.c > 201 struct ptp *ptp_get(void) > 202 { > 203 struct ptp *ptp = first_ptp_block; > ^^^^^^^^^^^^^^^^^^^^^^ > > 204 > 205 /* Check PTP block is present in hardware */ > 206 if (!pci_dev_present(ptp_id_table)) > 207 return ERR_PTR(-ENODEV); > 208 /* Check driver is bound to PTP block */ > 209 if (!ptp) > 210 ptp = ERR_PTR(-EPROBE_DEFER); > 211 else > 212 pci_dev_get(ptp->pdev); > ^^^^^^^^^ if first_ptp_block is an error pointer this will > Oops.
Will fix this in v3 patch.
Thanks, Sai > > 213 > 214 return ptp; > 215 } > > regards, > dan carpenter
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