Re: question about drivers/net/ethernet/ti/cpsw.c
From: David Miller <davem@davemloft.net>
Date: 2014-09-02 01:11:02
From: Julia Lawall <redacted> Date: Thu, 28 Aug 2014 21:26:55 +0200 (CEST)
I wonder if the following patch:
commit aa1a15e2d9199711cdcc9399fdb22544ab835a83
Author: Daniel Mack [off-list ref]
Date: Sat Sep 21 00:50:38 2013 +0530
introduced a race condition in drivers/net/ethernet/ti/cpsw.c. I was
looking at an old version of the file (Linux 3.10), and it has
clean_irq_ret:
for (i = 0; i < priv->num_irqs; i++)
free_irq(priv->irqs_table[i], priv);
at the beginning of the cleanup code of the probe function (cpsw_probe).
The above patch replaces request_irq by devm_request_irq and gets rid of
the above cleanup code. But that moves the stopping of the interrupts
after the following code at the end of the function:
free_netdev(priv->ndev);
The interrupt handler (cpsw_interrupt) does reference priv->ndev:
if (netif_running(priv->ndev)) {
napi_schedule(&priv->napi);
return IRQ_HANDLED;
}
so perhaps this could be a problem. The same happens in the remove
function.It could definitely be a problem. Probably it would be better for this device to request IRQs in open and release them in close like so many other networking drivers do.