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From: Evan Green <evgreen@chromium.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Rajat Jain <rajatja@google.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	linux-pci <linux-pci@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	x86@kernel.org, Marc Zyngier <maz@kernel.org>
Subject: Re: [PATCH v2] PCI/MSI: Avoid torn updates to MSI pairs
Date: Wed, 29 Jan 2020 10:00:59 -0800	[thread overview]
Message-ID: <CAE=gft69hQcbmT46b1T8eLdPFyb9Pp-sDYd5JfPsZ2JWL4PXqQ@mail.gmail.com> (raw)
In-Reply-To: <87pnf342pr.fsf@nanos.tec.linutronix.de>

On Tue, Jan 28, 2020 at 2:48 PM Thomas Gleixner <tglx@linutronix.de> wrote:
>
> Evan,
>
> Evan Green <evgreen@chromium.org> writes:
> > On Tue, Jan 28, 2020 at 6:38 AM Thomas Gleixner <tglx@linutronix.de> wrote:
> >> The patch is only lightly tested, but so far it survived.
> >>
> >
> > Hi Thomas,
> > Thanks for the patch, I gave it a try. I get the following splat, then a hang:
> >
> > [   62.238406]        CPU0
> > [   62.241135]        ----
> > [   62.243863]   lock(vector_lock);
> > [   62.247467]   lock(vector_lock);
> > [   62.251071]
> > [   62.251071]  *** DEADLOCK ***
> > [   62.251071]
> > [   62.257687]  May be due to missing lock nesting notation
> > [   62.257687]
> > [   62.265274] 2 locks held by migration/1/17:
> > [   62.269946]  #0: 00000000cfa9d8c3 (&irq_desc_lock_class){-.-.}, at:
> > irq_migrate_all_off_this_cpu+0x44/0x28f
> > [   62.280846]  #1: 000000006885da2d (vector_lock){-.-.}, at:
> > msi_set_affinity+0x13c/0x27b
> > [   62.289801]
> > [   62.289801] stack backtrace:
> > [   62.294669] CPU: 1 PID: 17 Comm: migration/1 Not tainted 4.19.96 #2
> > [   62.310713] Call Trace:
> > [   62.313446]  dump_stack+0xac/0x11e
> > [   62.317255]  __lock_acquire+0x64f/0x19bc
> > [   62.321646]  ? find_held_lock+0x3d/0xb8
> > [   62.325936]  ? pci_conf1_write+0x4f/0xdf
> > [   62.330320]  lock_acquire+0x1b2/0x1fa
> > [   62.334413]  ? apic_retrigger_irq+0x31/0x63
> > [   62.339097]  _raw_spin_lock_irqsave+0x51/0x7d
> > [   62.343972]  ? apic_retrigger_irq+0x31/0x63
> > [   62.348646]  apic_retrigger_irq+0x31/0x63
> > [   62.353124]  msi_set_affinity+0x25a/0x27b
>
> Bah. I'm sure I looked at that call chain, noticed the double vector
> lock and then forgot. Delta patch below.

It's working well with the delta patch, been running for about an hour
with no issues.
-Evan

  reply	other threads:[~2020-01-29 18:02 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-18  0:25 [PATCH v2] PCI/MSI: Avoid torn updates to MSI pairs Evan Green
2020-01-22 11:25 ` Rajat Jain
2020-01-22 18:00   ` Evan Green
2020-01-23  8:49     ` Thomas Gleixner
2020-01-23 18:16       ` Thomas Gleixner
     [not found]         ` <CAE=gft6YiM5S1A7iJYJTd5zmaAa8=nhLE3B94JtWa+XW-qVSqQ@mail.gmail.com>
2020-01-23 22:59           ` Evan Green
2020-01-24  0:29             ` Evan Green
2020-01-24 14:34               ` Thomas Gleixner
2020-01-24 21:53                 ` Evan Green
2020-01-24 22:50                   ` Thomas Gleixner
2020-01-28 14:38                     ` Thomas Gleixner
2020-01-28 22:22                       ` Evan Green
2020-01-28 22:48                         ` Thomas Gleixner
2020-01-29 18:00                           ` Evan Green [this message]
2020-01-29 21:00                             ` Thomas Gleixner
2020-01-29 22:53                               ` Evan Green
2020-01-29 23:16                                 ` Thomas Gleixner
2020-01-29 23:48                                   ` Evan Green
2020-01-31 11:27                                     ` [PATCH] x86/apic/msi: Plug non-maskable MSI affinity race Thomas Gleixner
2020-01-31 14:26                                       ` [PATCH V2] " Thomas Gleixner
2020-01-31 20:32                                         ` Evan Green
2020-01-31 21:45                                           ` Thomas Gleixner
     [not found]                                       ` <20200205144509.7004C21D7D@mail.kernel.org>
2020-02-05 14:58                                         ` [PATCH] " Thomas Gleixner
2020-02-05 20:18                                           ` Sasha Levin
2020-01-24  0:50             ` [PATCH v2] PCI/MSI: Avoid torn updates to MSI pairs Thomas Gleixner

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