On 11/19/2024 1:36 PM, Vincent Mailhol wrote:
On 19/11/2024 at 20:26, Vincent Mailhol wrote:
On 19/11/2024 at 19:01, Ciprian Marian Costea wrote:
On 11/19/2024 11:26 AM, Vincent Mailhol wrote:
On 19/11/2024 at 17:10, Ciprian Costea wrote:
(...)
+ if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SECONDARY_MB_IRQ) {
+ err = request_irq(priv->irq_secondary_mb,
+ flexcan_irq, IRQF_SHARED, dev->name, dev);
+ if (err)
+ goto out_free_irq_err;
+ }
Is the logic here correct?
request_irq(priv->irq_err, flexcan_irq, IRQF_SHARED, dev->name, dev);
is called only if the device has the FLEXCAN_QUIRK_NR_IRQ_3 quirk.
So, if the device has the FLEXCAN_QUIRK_SECONDARY_MB_IRQ but not the
FLEXCAN_QUIRK_NR_IRQ_3, you may end up trying to free an irq which was
not initialized.
Did you confirm if it is safe to call free_irq() on an uninitialized irq?
(and I can see that currently there is no such device with
FLEXCAN_QUIRK_SECONDARY_MB_IRQ but without FLEXCAN_QUIRK_NR_IRQ_3, but
who knows if such device will be introduced in the future?)
Hello Vincent,
Thanks for your review. Indeed this seems to be an incorrect logic since
I do not want to create any dependency between 'FLEXCAN_QUIRK_NR_IRQ_3'
and 'FLEXCAN_QUIRK_SECONDARY_MB_IRQ'.
I will change the impacted section to:
if (err) {
if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3)
goto out_free_irq_err;
else
goto out_free_irq;
}
This is better. Alternatively, you could move the check into the label:
out_free_irq_err:
if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3)
free_irq(priv->irq_err, dev);
But this is not a strong preference, I let you pick the one which you
prefer.
On second thought, it is a strong preference. If you keep the
if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3)
goto out_free_irq_err;
else
goto out_free_irq;
then what if more code with a clean-up label is added to flexcan_open()?
I am thinking of this:
out_free_foo:
free(foo);
out_free_irq_err:
free_irq(priv-irq_err, dev);
out_free_irq_boff:
free_irq(priv->irq_boff, dev);
Jumping to out_free_foo would now be incorrect because the
out_free_irq_err label would also be visited.
Correct, moving the check under the label would be better. Thanks.
I will change accordingly in V2.
Best Regards,
Ciprian
flexcan_chip_interrupts_enable(dev);
netif_start_queue(dev);
return 0;
+ out_free_irq_err:
+ free_irq(priv->irq_err, dev);
out_free_irq_boff:
free_irq(priv->irq_boff, dev);
out_free_irq:
(...)
Yours sincerely,
Vincent Mailhol
