From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nikolay Aleksandrov Subject: Re: [PATCH net] sfc: fix calling of free_irq with 0 argument Date: Tue, 06 May 2014 17:34:38 +0200 Message-ID: <5369010E.2060908@redhat.com> References: <1399380556-25797-1-git-send-email-nikolay@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Nikolay Aleksandrov , linux-net-drivers@solarflare.com, Shradha Shah , "David S. Miller" , Ben Hutchings To: netdev@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:3376 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755170AbaEFPj3 (ORCPT ); Tue, 6 May 2014 11:39:29 -0400 In-Reply-To: <1399380556-25797-1-git-send-email-nikolay@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On 05/06/2014 02:49 PM, Nikolay Aleksandrov wrote: > If the sfc driver is in legacy interrupt mode (either explicitly by > using interrupt_mode module param or by falling back to it) it will > hit a warning at kernel/irq/manage.c because it will try to free irq 0 > in efx_nic_fini_interrupt() since the MSI interrupts were freed always, > but in legacy irq mode they're == 0. So fix it by checking if we > actually have an interrupt allocated and only then free it. > > CC: > CC: Shradha Shah > CC: David S. Miller > > Reported-by: Zenghui Shi > Signed-off-by: Nikolay Aleksandrov > --- > There're other ways to fix this as well, but I chose this one as it follows > the logic in the code. Also I saw it used in a few places to check if > there's an IRQ allocated for that channel. > > drivers/net/ethernet/sfc/nic.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/sfc/nic.c b/drivers/net/ethernet/sfc/nic.c > index 32d969e857f7..cab627defbc3 100644 > --- a/drivers/net/ethernet/sfc/nic.c > +++ b/drivers/net/ethernet/sfc/nic.c > @@ -158,7 +158,9 @@ void efx_nic_fini_interrupt(struct efx_nic *efx) > > /* Disable MSI/MSI-X interrupts */ > efx_for_each_channel(channel, efx) > - free_irq(channel->irq, &efx->msi_context[channel->channel]); > + if (channel->irq) > + free_irq(channel->irq, > + &efx->msi_context[channel->channel]); > > /* Disable legacy interrupt */ > if (efx->legacy_irq) > And of course if I had looked deeper in the history of that function I would've seen that the code was like that before commit 1899c111a535e43046b14ae13639747d9d2544d6 ("sfc: Fix IRQ cleanup in case of a probe failure"). So including Ben on the CC list as he's the author of that commit. Cheers, Nik