From: Oliver O'Halloran <oohall@gmail.com>
To: Alex_Gagniuc@Dellteam.com, gregkh@linuxfoundation.org
Cc: keith.busch@intel.com, helgaas@kernel.org, mr.nuke.me@gmail.com,
linux-pci@vger.kernel.org, Austin.Bolen@dell.com,
Shyam.Iyer@dell.com, linux-kernel@vger.kernel.org,
jonathan.derrick@intel.com, lukas@wunner.de, ruscur@russell.cc,
sbobroff@linux.ibm.com, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2] PCI/MSI: Don't touch MSI bits when the PCI device is disconnected
Date: Mon, 12 Nov 2018 16:49:59 +1100 [thread overview]
Message-ID: <5da8d8aa9f3818af649b1ac547bc4e6062626ddf.camel@gmail.com> (raw)
In-Reply-To: <16bf9d14bc5f4a90b2b88dd2eb165186@ausx13mps321.AMER.DELL.COM>
On Thu, 2018-11-08 at 23:06 +0000, Alex_Gagniuc@Dellteam.com wrote:
> On 11/08/2018 04:51 PM, Greg KH wrote:
> > On Thu, Nov 08, 2018 at 10:49:08PM +0000, Alex_Gagniuc@Dellteam.com wrote:
> > > In the case that we're trying to fix, this code executing is a result of
> > > the device being gone, so we can guarantee race-free operation. I agree
> > > that there is a race, in the general case. As far as checking the result
> > > for all F's, that's not an option when firmware crashes the system as a
> > > result of the mmio read/write. It's never pretty when firmware gets
> > > involved.
> >
> > If you have firmware that crashes the system when you try to read from a
> > PCI device that was hot-removed, that is broken firmware and needs to be
> > fixed. The kernel can not work around that as again, you will never win
> > that race.
>
> But it's not the firmware that crashes. It's linux as a result of a
> fatal error message from the firmware. And we can't fix that because FFS
> handling requires that the system reboots [1].
Do we know the exact circumsances that result in firmware requesting a
reboot? If it happen on any PCIe error I don't see what we can do to
prevent that beyond masking UEs entirely (are we even allowed to do
that on FFS systems?).
> If we're going to say that we don't want to support FFS because it's a
> separate code path, and different flow, that's fine. I am myself, not a
> fan of FFS. But if we're going to continue supporting it, I think we'll
> continue to have to resolve these sort of unintended consequences.
>
> Alex
>
> [1] ACPI 6.2, 18.1 - Hardware Errors and Error Sources
next prev parent reply other threads:[~2018-11-12 5:50 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-18 22:15 [PATCH v2] PCI/MSI: Don't touch MSI bits when the PCI device is disconnected Alexandru Gagniuc
2018-11-06 0:32 ` Alex G.
2018-11-07 17:04 ` Derrick, Jonathan
2018-11-07 23:42 ` Bjorn Helgaas
2018-11-08 20:09 ` Bjorn Helgaas
2018-11-08 21:49 ` Keith Busch
2018-11-08 22:01 ` Greg Kroah-Hartman
2018-11-08 22:32 ` Keith Busch
2018-11-08 22:42 ` Greg Kroah-Hartman
2018-11-08 22:49 ` Alex_Gagniuc
2018-11-08 22:51 ` Greg KH
2018-11-08 23:06 ` Alex_Gagniuc
2018-11-12 5:49 ` Oliver O'Halloran [this message]
2018-11-12 20:05 ` Alex_Gagniuc
2018-11-13 5:02 ` Bjorn Helgaas
2018-11-13 22:39 ` Alex_Gagniuc
2018-11-13 22:52 ` Keith Busch
2018-11-14 0:31 ` Alex_Gagniuc
2018-11-14 5:59 ` Bjorn Helgaas
2018-11-14 19:22 ` Alex_Gagniuc
2018-11-14 19:41 ` Derrick, Jonathan
2018-11-14 20:23 ` Keith Busch
2018-11-14 20:52 ` Alex_Gagniuc
2018-11-14 20:58 ` Keith Busch
2018-11-15 6:24 ` Bjorn Helgaas
2018-11-16 0:19 ` Alex_Gagniuc
2018-11-08 23:03 ` Keith Busch
2018-11-09 7:29 ` Lukas Wunner
2018-11-09 11:32 ` Greg Kroah-Hartman
2018-11-09 16:36 ` Keith Busch
2018-11-08 22:20 ` Alex_Gagniuc
2018-11-09 7:11 ` Lukas Wunner
2018-11-12 5:48 ` Oliver O'Halloran
2018-12-27 19:28 ` Alex_Gagniuc
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5da8d8aa9f3818af649b1ac547bc4e6062626ddf.camel@gmail.com \
--to=oohall@gmail.com \
--cc=Alex_Gagniuc@Dellteam.com \
--cc=Austin.Bolen@dell.com \
--cc=Shyam.Iyer@dell.com \
--cc=gregkh@linuxfoundation.org \
--cc=helgaas@kernel.org \
--cc=jonathan.derrick@intel.com \
--cc=keith.busch@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=lukas@wunner.de \
--cc=mr.nuke.me@gmail.com \
--cc=ruscur@russell.cc \
--cc=sbobroff@linux.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).