From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.136]:33428 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754010AbcFTSf3 (ORCPT ); Mon, 20 Jun 2016 14:35:29 -0400 Date: Mon, 20 Jun 2016 13:34:28 -0500 From: Bjorn Helgaas To: David Miller Cc: bhelgaas@google.com, linux-pci@vger.kernel.org Subject: Re: [PATCH] pci: Fix unaligned accesses in VC code. Message-ID: <20160620183428.GA31564@localhost> References: <20160618.235225.1591502152749272620.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20160618.235225.1591502152749272620.davem@davemloft.net> Sender: linux-pci-owner@vger.kernel.org List-ID: On Sat, Jun 18, 2016 at 11:52:25PM -0700, David Miller wrote: > > The save/restore buffers for VC state is first composed of a 2-byte > control register, then a bunch of 4-byte words. > > This causes unaligned accesses which trap on platform such as sparc. > > This is easy to fix by simply moving the buffer pointer forward by 4 > bytes instead of 2 after dealing with the control register. The > length adjustment needs to be changed likewise as well. > > Reported-by: Meelis Roos > Reported-by: Anatoly Pugachev > Signed-off-by: David S. Miller Applied to for-linus for v4.7, thanks. I'm pretty sure this problem was introduced by 5f8fc43217a0 ("PCI: Include pci/pcie/Kconfig directly from pci/Kconfig"), which appeared in v4.6. This effectively made PCIe services, including VC, available on sparc. I added a stable tag for v4.6. > diff --git a/drivers/pci/vc.c b/drivers/pci/vc.c > index dfbab61..1fa3a32 100644 > --- a/drivers/pci/vc.c > +++ b/drivers/pci/vc.c > @@ -221,9 +221,9 @@ static int pci_vc_do_save_buffer(struct pci_dev *dev, int pos, > else > pci_write_config_word(dev, pos + PCI_VC_PORT_CTRL, > *(u16 *)buf); > - buf += 2; > + buf += 4; > } > - len += 2; > + len += 4; > > /* > * If we have any Low Priority VCs and a VC Arbitration Table Offset > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html