From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Shreeya Patel <shreeya.patel@collabora.com>
Cc: saravanak@google.com,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, "John Stultz" <jstultz@google.com>,
"David S. Miller" <davem@davemloft.net>,
"Alexey Kuznetsov" <kuznet@ms2.inr.ac.ru>,
"Hideaki YOSHIFUJI" <yoshfuji@linux-ipv6.org>,
"Jakub Kicinski" <kuba@kernel.org>,
"Rob Herring" <robh@kernel.org>,
"Yoshihiro Shimoda" <yoshihiro.shimoda.uh@renesas.com>,
"Robin Murphy" <robin.murphy@arm.com>,
"Andy Shevchenko" <andy.shevchenko@gmail.com>,
"Sudeep Holla" <sudeep.holla@arm.com>,
"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
"Naresh Kamboju" <naresh.kamboju@linaro.org>,
"Basil Eljuse" <Basil.Eljuse@arm.com>,
"Ferry Toth" <fntoth@gmail.com>, "Arnd Bergmann" <arnd@arndb.de>,
"Anders Roxell" <anders.roxell@linaro.org>,
linux-pm@vger.kernel.org, "Nathan Chancellor" <nathan@kernel.org>,
"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>,
"Geert Uytterhoeven" <geert+renesas@glider.be>,
"Rafael J. Wysocki" <rafael@kernel.org>,
"Linus Torvalds" <torvalds@linux-foundation.org>,
"Sasha Levin" <sashal@kernel.org>,
linux-kernel@vger.kernel.org,
"gustavo.padovan@collabora.com" <gustavo.padovan@collabora.com>,
"Ricardo Cañuelo Navarro" <ricardo.canuelo@collabora.com>,
"Guillaume Charles Tucker" <guillaume.tucker@collabora.com>,
usama.anjum@collabora.com, kernelci@lists.linux.dev
Subject: Re: [PATCH 5.17 127/298] driver core: Fix wait_for_device_probe() & deferred_probe_timeout interaction
Date: Wed, 16 Aug 2023 12:10:53 +0200 [thread overview]
Message-ID: <CAMuHMdVrWotHv5qTW0j_=uZsmwv7Vrkg-rm-=U=YbffsSfwfCg@mail.gmail.com> (raw)
In-Reply-To: <6283c4b1-2513-207d-4ed6-fdabf3f3880e@collabora.com>
Hi Shreeya,
On Wed, Aug 16, 2023 at 11:39 AM Shreeya Patel
<shreeya.patel@collabora.com> wrote:
> On 13/06/22 15:40, Greg Kroah-Hartman wrote:
> > From: Saravana Kannan<saravanak@google.com>
> >
> > [ Upstream commit 5ee76c256e928455212ab759c51d198fedbe7523 ]
> >
> > Mounting NFS rootfs was timing out when deferred_probe_timeout was
> > non-zero [1]. This was because ip_auto_config() initcall times out
> > waiting for the network interfaces to show up when
> > deferred_probe_timeout was non-zero. While ip_auto_config() calls
> > wait_for_device_probe() to make sure any currently running deferred
> > probe work or asynchronous probe finishes, that wasn't sufficient to
> > account for devices being deferred until deferred_probe_timeout.
> >
> > Commit 35a672363ab3 ("driver core: Ensure wait_for_device_probe() waits
> > until the deferred_probe_timeout fires") tried to fix that by making
> > sure wait_for_device_probe() waits for deferred_probe_timeout to expire
> > before returning.
> >
> > However, if wait_for_device_probe() is called from the kernel_init()
> > context:
> >
> > - Before deferred_probe_initcall() [2], it causes the boot process to
> > hang due to a deadlock.
> >
> > - After deferred_probe_initcall() [3], it blocks kernel_init() from
> > continuing till deferred_probe_timeout expires and beats the point of
> > deferred_probe_timeout that's trying to wait for userspace to load
> > modules.
> >
> > Neither of this is good. So revert the changes to
> > wait_for_device_probe().
> >
> > [1] -https://lore.kernel.org/lkml/TYAPR01MB45443DF63B9EF29054F7C41FD8C60@TYAPR01MB4544.jpnprd01.prod.outlook.com/
> > [2] -https://lore.kernel.org/lkml/YowHNo4sBjr9ijZr@dev-arch.thelio-3990X/
> > [3] -https://lore.kernel.org/lkml/Yo3WvGnNk3LvLb7R@linutronix.de/
>
> Hi Saravana, Greg,
>
>
> KernelCI found this patch causes the baseline.bootrr.deferred-probe-empty test to fail on r8a77960-ulcb,
> see the following details for more information.
Commit 9be4cbd09da820a2 ("driver core: Set default deferred_probe_timeout
back to 0.") in v5.19 contains a reference to the same commit as
mentioned in the Fixes tag. Does backporting that help?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2023-08-16 10:12 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220613094924.913340374@linuxfoundation.org>
2022-06-13 10:10 ` [PATCH 5.17 127/298] driver core: Fix wait_for_device_probe() & deferred_probe_timeout interaction Greg Kroah-Hartman
2023-08-16 9:39 ` Shreeya Patel
2023-08-16 10:10 ` Geert Uytterhoeven [this message]
2023-08-16 10:15 ` Geert Uytterhoeven
2023-08-16 15:03 ` Greg Kroah-Hartman
2023-08-17 11:36 ` Shreeya Patel
2023-08-17 18:33 ` Saravana Kannan
2023-08-17 23:13 ` Shreeya Patel
2023-08-18 20:19 ` Saravana Kannan
2023-08-21 11:35 ` Shreeya Patel
2023-08-21 12:39 ` Robin Murphy
2023-08-21 13:11 ` Mark Brown
2023-08-22 14:10 ` Shreeya Patel
2023-08-23 20:59 ` Saravana Kannan
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