From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Keith Busch <keith.busch@intel.com>
Cc: poza@codeaurora.org, Sinan Kaya <okaya@kernel.org>,
Bjorn Helgaas <helgaas@kernel.org>,
Thomas Tai <thomas.tai@oracle.com>,
bhelgaas@google.com, linux-pci@vger.kernel.org,
linux-pci-owner@vger.kernel.org,
Sam Bobroff <sam.bobroff@au1.ibm.com>
Subject: Re: [PATCH 1/1] PCI/AER: prevent pcie_do_fatal_recovery from using device after it is removed
Date: Wed, 22 Aug 2018 10:36:20 +1000 [thread overview]
Message-ID: <7e151e06dc7742d23b907d5487265e72787acbd0.camel@kernel.crashing.org> (raw)
In-Reply-To: <20180821231308.GB19320@localhost.localdomain>
On Tue, 2018-08-21 at 17:13 -0600, Keith Busch wrote:
> On Wed, Aug 22, 2018 at 09:06:57AM +1000, Benjamin Herrenschmidt wrote:
> > On Tue, 2018-08-21 at 16:04 -0600, Keith Busch wrote:
> > > > I think there need to be some coordination between pciehb and DPC on
> > > > link state change yes.
> > > >
> > > > We could still remove the device if recovery fails. For example on EEH
> > > > we have a threshold and if a device fails more than N times within the
> > > > last M minutes (I don't remember the exact numbers and I'm not in front
> > > > of the code right now) we give up.
> > > >
> > > > Also under some circumstances, the link will change as a result of the
> > > > error handling doing a hot reset.
> > > >
> > > > For example, if the error happens in a parent bridge and that gets
> > > > reset, the entire hierarchy underneath does too.
> > > >
> > > > We need to save/restore the state of all bridges and devices (BARs
> > > > etc...) below that.
> > >
> > > That's not good enough. You'd at least need to check SLTSTS.PDC on all
> > > bridge DSP's beneath the parent *before* you try to restore the state
> > > of devices beneath them. Those races are primarily why DPC currently
> > > removes and reenumerates instead, because that's not something that can
> > > be readily coordinated today.
> >
> > It can be probably done by a simple test & skip as you go down
> > restoring state, then handling the removals after the dance is
> > complete.
>
> You can't just test the states in config space. You're racing with
> pciehp's ISR, which clears those states.
Sure, I meant you'd call into pciehp.. For EEH we do have some linkage
between hotplug and EEH, though a lot of it goes at the FW level for
us.
> You'd need to fundamentally
> change pciehp to (1) not process such events until some currently
> undefined criteria is established, and (2) save and export the previously
> latched states while pciehp bottom half processing is stalled.
Ben.
next prev parent reply other threads:[~2018-08-22 0:36 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-13 16:51 [PATCH 0/1] PCI/AER: prevent pcie_do_fatal_recovery from using device after it is removed Thomas Tai
2018-08-13 16:51 ` [PATCH 1/1] " Thomas Tai
2018-08-14 9:16 ` poza
2018-08-14 9:22 ` poza
2018-08-14 13:51 ` Thomas Tai
2018-08-15 14:57 ` poza
2018-08-15 15:02 ` Thomas Tai
2018-08-15 15:26 ` poza
2018-08-15 15:43 ` Thomas Tai
2018-08-15 15:59 ` poza
2018-08-15 16:04 ` Thomas Tai
2018-08-15 21:55 ` Benjamin Herrenschmidt
2018-08-15 21:56 ` Benjamin Herrenschmidt
2018-08-16 6:36 ` poza
2018-08-16 6:51 ` Benjamin Herrenschmidt
2018-08-16 6:59 ` Benjamin Herrenschmidt
2018-08-16 8:07 ` poza
2018-08-16 8:12 ` Benjamin Herrenschmidt
2018-08-16 9:03 ` poza
2018-08-16 10:07 ` Benjamin Herrenschmidt
2018-08-16 14:11 ` poza
2018-08-16 23:30 ` Benjamin Herrenschmidt
2018-08-17 10:29 ` poza
2018-08-17 10:44 ` poza
2018-08-18 7:38 ` Benjamin Herrenschmidt
2018-08-16 7:05 ` Benjamin Herrenschmidt
2018-08-16 7:15 ` Benjamin Herrenschmidt
2018-08-16 7:56 ` poza
2018-08-16 8:10 ` Benjamin Herrenschmidt
2018-08-16 8:05 ` poza
2018-08-16 8:15 ` Benjamin Herrenschmidt
2018-08-16 8:22 ` poza
2018-08-16 8:28 ` Benjamin Herrenschmidt
2018-08-16 13:30 ` Thomas Tai
2018-08-16 13:46 ` Sinan Kaya
2018-08-16 23:27 ` Benjamin Herrenschmidt
2018-08-17 6:35 ` poza
2018-08-19 2:24 ` Bjorn Helgaas
2018-08-20 5:09 ` poza
2018-08-20 5:15 ` Benjamin Herrenschmidt
2018-08-20 13:02 ` Thomas Tai
2018-08-20 13:27 ` Benjamin Herrenschmidt
2018-08-19 2:19 ` Bjorn Helgaas
2018-08-19 21:41 ` Sinan Kaya
2018-08-20 2:03 ` Benjamin Herrenschmidt
2018-08-20 5:19 ` poza
2018-08-20 5:33 ` Benjamin Herrenschmidt
2018-08-20 7:56 ` poza
2018-08-20 11:22 ` Benjamin Herrenschmidt
2018-08-20 13:26 ` poza
2018-08-20 21:02 ` Benjamin Herrenschmidt
2018-08-21 5:14 ` poza
2018-08-21 6:06 ` Benjamin Herrenschmidt
2018-08-21 14:37 ` Keith Busch
2018-08-21 15:07 ` Sinan Kaya
2018-08-21 15:29 ` Keith Busch
2018-08-21 15:50 ` Sinan Kaya
2018-08-21 15:55 ` Sinan Kaya
2018-08-21 16:44 ` Keith Busch
2018-08-21 15:30 ` poza
2018-08-21 21:14 ` Benjamin Herrenschmidt
2018-08-21 22:04 ` Keith Busch
2018-08-21 22:33 ` Keith Busch
2018-08-21 23:06 ` Benjamin Herrenschmidt
2018-08-21 23:13 ` Keith Busch
2018-08-22 0:36 ` Benjamin Herrenschmidt [this message]
2018-08-30 0:01 ` Keith Busch
2018-08-30 0:10 ` Sinan Kaya
2018-08-30 0:46 ` Keith Busch
2018-08-30 4:26 ` Benjamin Herrenschmidt
2018-08-20 15:53 ` Keith Busch
2018-08-20 16:13 ` poza
2018-08-20 16:32 ` Keith Busch
2018-08-20 21:05 ` Benjamin Herrenschmidt
2018-08-20 21:21 ` Sinan Kaya
2018-08-20 21:35 ` Keith Busch
2018-08-20 21:53 ` Benjamin Herrenschmidt
2018-08-20 22:02 ` Sinan Kaya
2018-08-20 22:04 ` Benjamin Herrenschmidt
2018-08-20 22:13 ` Sinan Kaya
2018-08-20 22:19 ` Benjamin Herrenschmidt
2018-08-22 9:13 ` Lukas Wunner
2018-08-22 14:38 ` Keith Busch
2018-08-22 14:51 ` Sinan Kaya
2018-08-20 22:13 ` Keith Busch
2018-08-20 22:19 ` Benjamin Herrenschmidt
2018-08-21 1:30 ` Keith Busch
2018-08-20 4:37 ` Benjamin Herrenschmidt
2018-08-20 4:39 ` PATCH] Partial revert of "PCI/AER: Handle ERR_FATAL with removal and re-enumeration of devices" Benjamin Herrenschmidt
2018-08-21 19:50 ` Bjorn Helgaas
2018-08-22 4:35 ` poza
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=7e151e06dc7742d23b907d5487265e72787acbd0.camel@kernel.crashing.org \
--to=benh@kernel.crashing.org \
--cc=bhelgaas@google.com \
--cc=helgaas@kernel.org \
--cc=keith.busch@intel.com \
--cc=linux-pci-owner@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=okaya@kernel.org \
--cc=poza@codeaurora.org \
--cc=sam.bobroff@au1.ibm.com \
--cc=thomas.tai@oracle.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).