[PATCH 5.4 39/84] driver core: Set deferred_probe_timeout to a longer default if CONFIG_MODULES is set

[PATCH 5.4 39/84] driver core: Set deferred_probe_timeout to a longer default if CONFIG_MODULES is set

[Greg Kroah-Hartman]

5.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: John Stultz <john.stultz@linaro.org>

[ Upstream commit e2cec7d6853712295cef5377762165a489b2957f ]

When using modules, its common for the modules not to be loaded
until quite late by userland. With the current code,
driver_deferred_probe_check_state() will stop returning
EPROBE_DEFER after late_initcall, which can cause module
dependency resolution to fail after that.

So allow a longer window of 30 seconds (picked somewhat
arbitrarily, but influenced by the similar regulator core
timeout value) in the case where modules are enabled.

Cc: linux-pm@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Todd Kjos <tkjos@google.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kevin Hilman <khilman@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Rob Herring <robh@kernel.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/r/20200225050828.56458-3-john.stultz@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/base/dd.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 7941a8fd22841..0b97a0c96baa3 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -224,7 +224,16 @@ static int deferred_devs_show(struct seq_file *s, void *data)
 }
 DEFINE_SHOW_ATTRIBUTE(deferred_devs);
 
+#ifdef CONFIG_MODULES
+/*
+ * In the case of modules, set the default probe timeout to
+ * 30 seconds to give userland some time to load needed modules
+ */
+static int deferred_probe_timeout = 30;
+#else
+/* In the case of !modules, no probe timeout needed */
 static int deferred_probe_timeout = -1;
+#endif
 static int __init deferred_probe_timeout_setup(char *str)
 {
 	int timeout;
-- 
2.43.0

Re: [PATCH 5.4 39/84] driver core: Set deferred_probe_timeout to a longer default if CONFIG_MODULES is set

[John Stultz]

On Tue, Feb 27, 2024 at 5:27 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> 5.4-stable review patch.  If anyone has any objections, please let me know.
>
> ------------------
>
> From: John Stultz <john.stultz@linaro.org>
>
> [ Upstream commit e2cec7d6853712295cef5377762165a489b2957f ]
>
> When using modules, its common for the modules not to be loaded
> until quite late by userland. With the current code,
> driver_deferred_probe_check_state() will stop returning
> EPROBE_DEFER after late_initcall, which can cause module
> dependency resolution to fail after that.
>
> So allow a longer window of 30 seconds (picked somewhat
> arbitrarily, but influenced by the similar regulator core
> timeout value) in the case where modules are enabled.
>
> Cc: linux-pm@vger.kernel.org
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Cc: Thierry Reding <treding@nvidia.com>
> Cc: Mark Brown <broonie@kernel.org>
> Cc: Liam Girdwood <lgirdwood@gmail.com>
> Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
> Cc: Saravana Kannan <saravanak@google.com>
> Cc: Todd Kjos <tkjos@google.com>
> Cc: Len Brown <len.brown@intel.com>
> Cc: Pavel Machek <pavel@ucw.cz>
> Cc: Ulf Hansson <ulf.hansson@linaro.org>
> Cc: Kevin Hilman <khilman@kernel.org>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: Rob Herring <robh@kernel.org>
> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> Link: https://lore.kernel.org/r/20200225050828.56458-3-john.stultz@linaro.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>  drivers/base/dd.c | 9 +++++++++
>  1 file changed, 9 insertions(+)

This change ended up being reverted upstream in ce68929f07de

Is there some specific reason it got selected to be pulled into -stable?

thanks
-john

Re: [PATCH 5.4 39/84] driver core: Set deferred_probe_timeout to a longer default if CONFIG_MODULES is set

[Greg Kroah-Hartman]

On Tue, Feb 27, 2024 at 11:38:01AM -0800, John Stultz wrote:
> On Tue, Feb 27, 2024 at 5:27 AM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > 5.4-stable review patch.  If anyone has any objections, please let me know.
> >
> > ------------------
> >
> > From: John Stultz <john.stultz@linaro.org>
> >
> > [ Upstream commit e2cec7d6853712295cef5377762165a489b2957f ]
> >
> > When using modules, its common for the modules not to be loaded
> > until quite late by userland. With the current code,
> > driver_deferred_probe_check_state() will stop returning
> > EPROBE_DEFER after late_initcall, which can cause module
> > dependency resolution to fail after that.
> >
> > So allow a longer window of 30 seconds (picked somewhat
> > arbitrarily, but influenced by the similar regulator core
> > timeout value) in the case where modules are enabled.
> >
> > Cc: linux-pm@vger.kernel.org
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: Linus Walleij <linus.walleij@linaro.org>
> > Cc: Thierry Reding <treding@nvidia.com>
> > Cc: Mark Brown <broonie@kernel.org>
> > Cc: Liam Girdwood <lgirdwood@gmail.com>
> > Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
> > Cc: Saravana Kannan <saravanak@google.com>
> > Cc: Todd Kjos <tkjos@google.com>
> > Cc: Len Brown <len.brown@intel.com>
> > Cc: Pavel Machek <pavel@ucw.cz>
> > Cc: Ulf Hansson <ulf.hansson@linaro.org>
> > Cc: Kevin Hilman <khilman@kernel.org>
> > Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> > Cc: Rob Herring <robh@kernel.org>
> > Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> > Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > Signed-off-by: John Stultz <john.stultz@linaro.org>
> > Link: https://lore.kernel.org/r/20200225050828.56458-3-john.stultz@linaro.org
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Signed-off-by: Sasha Levin <sashal@kernel.org>
> > ---
> >  drivers/base/dd.c | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> 
> This change ended up being reverted upstream in ce68929f07de
> 
> Is there some specific reason it got selected to be pulled into -stable?

It was an attempt to sync up with what had been added to the 4.19.y tree
but not newer kernels.  I'll go drop this from 5.4.y now, thanks for
noticing the revert, my scripts did not pick that up :(

Also, this is in the 4.19.y tree, but in a different form, and one that
no one seemed to have problems with, so I'll leave it alone there for
now.

thanks,

greg k-h