linux-pci.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Bjorn Helgaas <helgaas@kernel.org>, Hari Vyas <hari.vyas@broadcom.com>
Cc: bhelgaas@google.com, linux-pci@vger.kernel.org, ray.jui@broadcom.com
Subject: Re: PCIe enable device races (Was: [PATCH v3] PCI: Data corruption happening due to race condition)
Date: Wed, 15 Aug 2018 14:16:33 +1000	[thread overview]
Message-ID: <5e42f7990673d11e3a020e7efcfd333215d48138.camel@kernel.crashing.org> (raw)
In-Reply-To: <ecaed7664b46d73888d2494065905f8e108fc0f4.camel@kernel.crashing.org>

On Wed, 2018-08-15 at 13:35 +1000, Benjamin Herrenschmidt wrote:
> What's really needed is a per device mutex covering all those operations
> on a given device. (This would also allow to get rid of those games with
> atomics).
> 
> Any comments ?

Note: I'm experienting with a per-pci_dev mutex to protect the device
state. If it works out, I suggest we add it, then progressively
move things one by one under the protection of the mutex.

Any objection to the approach ? If it fixes my problem, I'll send
preliminary patches that cover the basic enable/disable and bus
master settings to start with. We should try to get them into
stable as this is breaking real world stuff for us.

I suspect large x86 systems get lucky because their BIOSes do all
the enables. It would be possible to reproduce the races there by
hot-pluging a large external drawer using a cable card with a switch

Cheers,
Ben.
 

  reply	other threads:[~2018-08-15  4:16 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-03  9:05 [PATCH v3] PCI: Data corruption happening due to race condition Hari Vyas
2018-07-03  9:05 ` Hari Vyas
2018-07-03  9:13   ` Lukas Wunner
2018-07-18 23:29   ` Bjorn Helgaas
2018-07-19  4:18     ` Benjamin Herrenschmidt
2018-07-19 14:04       ` Hari Vyas
2018-07-19 18:55         ` Lukas Wunner
2018-07-20  4:27           ` Benjamin Herrenschmidt
2018-07-27 22:25       ` Bjorn Helgaas
2018-07-28  0:45         ` Benjamin Herrenschmidt
2018-07-31 11:21         ` Michael Ellerman
2018-07-19 17:41   ` Bjorn Helgaas
2018-07-20  9:16     ` Hari Vyas
2018-07-20 12:20       ` Bjorn Helgaas
2018-07-31 16:37 ` Bjorn Helgaas
2018-08-15  3:35   ` PCIe enable device races (Was: [PATCH v3] PCI: Data corruption happening due to race condition) Benjamin Herrenschmidt
2018-08-15  4:16     ` Benjamin Herrenschmidt [this message]
2018-08-15  4:44       ` Benjamin Herrenschmidt
2018-08-15  5:21         ` [RFC PATCH] pci: Proof of concept at fixing pci_enable_device/bridge races Benjamin Herrenschmidt
2018-08-15 19:09         ` PCIe enable device races (Was: [PATCH v3] PCI: Data corruption happening due to race condition) Bjorn Helgaas
2018-08-15 21:50         ` [RFC PATCH] pci: Proof of concept at fixing pci_enable_device/bridge races Benjamin Herrenschmidt
2018-08-15 22:40           ` Guenter Roeck
2018-08-15 23:38             ` Benjamin Herrenschmidt
2018-08-20  1:31               ` Guenter Roeck
2018-08-17  3:07           ` Bjorn Helgaas
2018-08-17  3:42             ` Benjamin Herrenschmidt
2018-08-15 18:50     ` PCIe enable device races (Was: [PATCH v3] PCI: Data corruption happening due to race condition) Bjorn Helgaas
2018-08-15 21:52       ` Benjamin Herrenschmidt
2018-08-15 23:23         ` Benjamin Herrenschmidt
2018-08-16  7:58         ` Konstantin Khlebnikov
2018-08-16  8:02           ` Benjamin Herrenschmidt
2018-08-16  9:22             ` Hari Vyas
2018-08-16 10:10               ` Benjamin Herrenschmidt
2018-08-16 10:11                 ` Benjamin Herrenschmidt
2018-08-16 10:26                 ` Lukas Wunner
2018-08-16 10:47                   ` Hari Vyas
2018-08-16 23:20                     ` Benjamin Herrenschmidt
2018-08-16 23:17                   ` Benjamin Herrenschmidt
2018-08-17  0:43                     ` Benjamin Herrenschmidt
2018-08-16 19:43             ` Jens Axboe
2018-08-16 21:37               ` Benjamin Herrenschmidt
2018-08-16 21:56                 ` Jens Axboe
2018-08-16 23:09                   ` Benjamin Herrenschmidt
2018-08-17  0:14                     ` Jens Axboe
2018-08-16 12:28         ` Lukas Wunner
2018-08-16 23:25           ` Benjamin Herrenschmidt
2018-08-17  1:12             ` Benjamin Herrenschmidt
2018-08-17 16:39               ` Lukas Wunner
2018-08-18  3:37                 ` Benjamin Herrenschmidt
2018-08-18  9:22                   ` Lukas Wunner
2018-08-18 13:11                     ` Benjamin Herrenschmidt

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=5e42f7990673d11e3a020e7efcfd333215d48138.camel@kernel.crashing.org \
    --to=benh@kernel.crashing.org \
    --cc=bhelgaas@google.com \
    --cc=hari.vyas@broadcom.com \
    --cc=helgaas@kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=ray.jui@broadcom.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).