From: "Paul E. McKenney" <paulmck@kernel.org>
The srcu_read_lock_nmisafe() and srcu_read_unlock_nmisafe() functions
map to __srcu_read_lock() and __srcu_read_unlock() on systems like x86
that have NMI-safe this_cpu_inc() operations. This makes the underlying
__srcu_read_lock_nmisafe() and __srcu_read_unlock_nmisafe() functions
difficult to test on (for example) x86 systems, allowing bugs to creep in.
This commit therefore creates a FORCE_NEED_SRCU_NMI_SAFE Kconfig that
forces those underlying functions to be used even on systems where they
are not needed, thus providing better testing coverage.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
kernel/rcu/Kconfig | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index b9b6bc55185d..c8e540af3a35 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -65,6 +65,17 @@ config TREE_SRCU
help
This option selects the full-fledged version of SRCU.
+config FORCE_NEED_SRCU_NMI_SAFE
+ bool "Force selection of NEED_SRCU_NMI_SAFE"
+ depends on !TINY_SRCU
+ select NEED_SRCU_NMI_SAFE
+ default n
+ help
+ This option forces selection of the NEED_SRCU_NMI_SAFE
+ Kconfig option, allowing testing of srcu_read_lock_nmisafe()
+ and srcu_read_unlock_nmisafe() on architectures (like x86)
+ that select the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option.
+
config NEED_SRCU_NMI_SAFE
def_bool HAVE_NMI && !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && !TINY_SRCU
--
2.39.5 (Apple Git-154)Hi Boqun, Paul,
On Wed, 19 Feb 2025 at 16:44, Boqun Feng <boqun.feng@gmail.com> wrote:
> From: "Paul E. McKenney" <paulmck@kernel.org>
>
> The srcu_read_lock_nmisafe() and srcu_read_unlock_nmisafe() functions
> map to __srcu_read_lock() and __srcu_read_unlock() on systems like x86
> that have NMI-safe this_cpu_inc() operations. This makes the underlying
> __srcu_read_lock_nmisafe() and __srcu_read_unlock_nmisafe() functions
> difficult to test on (for example) x86 systems, allowing bugs to creep in.
>
> This commit therefore creates a FORCE_NEED_SRCU_NMI_SAFE Kconfig that
> forces those underlying functions to be used even on systems where they
> are not needed, thus providing better testing coverage.
>
> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Thanks for your patch, which is now commit 536e8b9b80bc7a0a ("srcu:
Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing") in linus/master
> --- a/kernel/rcu/Kconfig
> +++ b/kernel/rcu/Kconfig
> @@ -65,6 +65,17 @@ config TREE_SRCU
> help
> This option selects the full-fledged version of SRCU.
>
> +config FORCE_NEED_SRCU_NMI_SAFE
> + bool "Force selection of NEED_SRCU_NMI_SAFE"
What am I supposed to answer here? "n" I guess.
What about distro and allmodconfig kernels?
> + depends on !TINY_SRCU
> + select NEED_SRCU_NMI_SAFE
> + default n
> + help
> + This option forces selection of the NEED_SRCU_NMI_SAFE
> + Kconfig option, allowing testing of srcu_read_lock_nmisafe()
> + and srcu_read_unlock_nmisafe() on architectures (like x86)
> + that select the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option.
Perhaps this should depend on ARCH_HAS_NMI_SAFE_THIS_CPU_OPS?
> +
> config NEED_SRCU_NMI_SAFE
> def_bool HAVE_NMI && !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS && !TINY_SRCU
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
On Tue, Mar 25, 2025 at 09:04:31AM +0100, Geert Uytterhoeven wrote:
> Hi Boqun, Paul,
>
> On Wed, 19 Feb 2025 at 16:44, Boqun Feng <boqun.feng@gmail.com> wrote:
> > From: "Paul E. McKenney" <paulmck@kernel.org>
> >
> > The srcu_read_lock_nmisafe() and srcu_read_unlock_nmisafe() functions
> > map to __srcu_read_lock() and __srcu_read_unlock() on systems like x86
> > that have NMI-safe this_cpu_inc() operations. This makes the underlying
> > __srcu_read_lock_nmisafe() and __srcu_read_unlock_nmisafe() functions
> > difficult to test on (for example) x86 systems, allowing bugs to creep in.
> >
> > This commit therefore creates a FORCE_NEED_SRCU_NMI_SAFE Kconfig that
> > forces those underlying functions to be used even on systems where they
> > are not needed, thus providing better testing coverage.
> >
> > Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> > Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
>
> Thanks for your patch, which is now commit 536e8b9b80bc7a0a ("srcu:
> Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing") in linus/master
>
> > --- a/kernel/rcu/Kconfig
> > +++ b/kernel/rcu/Kconfig
> > @@ -65,6 +65,17 @@ config TREE_SRCU
> > help
> > This option selects the full-fledged version of SRCU.
> >
> > +config FORCE_NEED_SRCU_NMI_SAFE
> > + bool "Force selection of NEED_SRCU_NMI_SAFE"
>
> What am I supposed to answer here? "n" I guess.
> What about distro and allmodconfig kernels?
Yes, you should select "n" unless ...
> > + depends on !TINY_SRCU
> > + select NEED_SRCU_NMI_SAFE
> > + default n
> > + help
> > + This option forces selection of the NEED_SRCU_NMI_SAFE
> > + Kconfig option, allowing testing of srcu_read_lock_nmisafe()
> > + and srcu_read_unlock_nmisafe() on architectures (like x86)
> > + that select the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option.
>
> Perhaps this should depend on ARCH_HAS_NMI_SAFE_THIS_CPU_OPS?
... you are on a system selecting ARCH_HAS_NMI_SAFE_THIS_CPU_OPS and
you would like to test the SRCU setup that needed only by systems that
do not select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS.
Ah. I forgot to add "depends on RCU_EXPERT".
Apologies, I will fix this. Does the patch show below do the trick?
Thanx, Paul
------------------------------------------------------------------------
commit b5c8c6f89c6d7ac778e961ad4b883eada0c1f42a
Author: Paul E. McKenney <paulmck@kernel.org>
Date: Tue Mar 25 07:31:45 2025 -0700
srcu: Make FORCE_NEED_SRCU_NMI_SAFE depend on RCU_EXPERT
The FORCE_NEED_SRCU_NMI_SAFE is useful only for those wishing to test
the SRCU code paths that accommodate architectures that do not have
NMI-safe per-CPU operations, that is, those architectures that do not
select the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option. As such, this
is a specialized Kconfig option that is not intended for casual users.
This commit therefore hides it behind the RCU_EXPERT Kconfig option.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Closes: https://lore.kernel.org/all/CAMuHMdX6dy9_tmpLkpcnGzxyRbe6qSWYukcPp=H1GzZdyd3qBQ@mail.gmail.com/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index b3f985d41717a..cc4ce79f58aa6 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -68,6 +68,7 @@ config TREE_SRCU
config FORCE_NEED_SRCU_NMI_SAFE
bool "Force selection of NEED_SRCU_NMI_SAFE"
depends on !TINY_SRCU
+ depends on RCU_EXPERT
select NEED_SRCU_NMI_SAFE
default n
help
Hi Paul,
On Tue, 25 Mar 2025 at 15:36, Paul E. McKenney <paulmck@kernel.org> wrote:
> On Tue, Mar 25, 2025 at 09:04:31AM +0100, Geert Uytterhoeven wrote:
> > On Wed, 19 Feb 2025 at 16:44, Boqun Feng <boqun.feng@gmail.com> wrote:
> > > From: "Paul E. McKenney" <paulmck@kernel.org>
> > >
> > > The srcu_read_lock_nmisafe() and srcu_read_unlock_nmisafe() functions
> > > map to __srcu_read_lock() and __srcu_read_unlock() on systems like x86
> > > that have NMI-safe this_cpu_inc() operations. This makes the underlying
> > > __srcu_read_lock_nmisafe() and __srcu_read_unlock_nmisafe() functions
> > > difficult to test on (for example) x86 systems, allowing bugs to creep in.
> > >
> > > This commit therefore creates a FORCE_NEED_SRCU_NMI_SAFE Kconfig that
> > > forces those underlying functions to be used even on systems where they
> > > are not needed, thus providing better testing coverage.
> > >
> > > Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> > > Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> >
> > Thanks for your patch, which is now commit 536e8b9b80bc7a0a ("srcu:
> > Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing") in linus/master
> >
> > > --- a/kernel/rcu/Kconfig
> > > +++ b/kernel/rcu/Kconfig
> > > @@ -65,6 +65,17 @@ config TREE_SRCU
> > > help
> > > This option selects the full-fledged version of SRCU.
> > >
> > > +config FORCE_NEED_SRCU_NMI_SAFE
> > > + bool "Force selection of NEED_SRCU_NMI_SAFE"
> >
> > What am I supposed to answer here? "n" I guess.
> > What about distro and allmodconfig kernels?
>
> Yes, you should select "n" unless ...
>
> > > + depends on !TINY_SRCU
> > > + select NEED_SRCU_NMI_SAFE
> > > + default n
> > > + help
> > > + This option forces selection of the NEED_SRCU_NMI_SAFE
> > > + Kconfig option, allowing testing of srcu_read_lock_nmisafe()
> > > + and srcu_read_unlock_nmisafe() on architectures (like x86)
> > > + that select the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option.
> >
> > Perhaps this should depend on ARCH_HAS_NMI_SAFE_THIS_CPU_OPS?
>
> ... you are on a system selecting ARCH_HAS_NMI_SAFE_THIS_CPU_OPS and
So a dependency on ARCH_HAS_NMI_SAFE_THIS_CPU_OPS does make sense,
doesn't it?
> you would like to test the SRCU setup that needed only by systems that
> do not select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS.
>
> Ah. I forgot to add "depends on RCU_EXPERT".
Yes, that makes sense.
> Apologies, I will fix this. Does the patch show below do the trick?
>
> Thanx, Paul
>
> ------------------------------------------------------------------------
>
> commit b5c8c6f89c6d7ac778e961ad4b883eada0c1f42a
> Author: Paul E. McKenney <paulmck@kernel.org>
> Date: Tue Mar 25 07:31:45 2025 -0700
>
> srcu: Make FORCE_NEED_SRCU_NMI_SAFE depend on RCU_EXPERT
>
> The FORCE_NEED_SRCU_NMI_SAFE is useful only for those wishing to test
> the SRCU code paths that accommodate architectures that do not have
> NMI-safe per-CPU operations, that is, those architectures that do not
> select the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option. As such, this
> is a specialized Kconfig option that is not intended for casual users.
>
> This commit therefore hides it behind the RCU_EXPERT Kconfig option.
>
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Closes: https://lore.kernel.org/all/CAMuHMdX6dy9_tmpLkpcnGzxyRbe6qSWYukcPp=H1GzZdyd3qBQ@mail.gmail.com/
> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
>
> diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
> index b3f985d41717a..cc4ce79f58aa6 100644
> --- a/kernel/rcu/Kconfig
> +++ b/kernel/rcu/Kconfig
> @@ -68,6 +68,7 @@ config TREE_SRCU
> config FORCE_NEED_SRCU_NMI_SAFE
> bool "Force selection of NEED_SRCU_NMI_SAFE"
> depends on !TINY_SRCU
> + depends on RCU_EXPERT
> select NEED_SRCU_NMI_SAFE
> default n
> 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
On Tue, Mar 25, 2025 at 03:57:43PM +0100, Geert Uytterhoeven wrote:
> Hi Paul,
>
> On Tue, 25 Mar 2025 at 15:36, Paul E. McKenney <paulmck@kernel.org> wrote:
> > On Tue, Mar 25, 2025 at 09:04:31AM +0100, Geert Uytterhoeven wrote:
> > > On Wed, 19 Feb 2025 at 16:44, Boqun Feng <boqun.feng@gmail.com> wrote:
> > > > From: "Paul E. McKenney" <paulmck@kernel.org>
> > > >
> > > > The srcu_read_lock_nmisafe() and srcu_read_unlock_nmisafe() functions
> > > > map to __srcu_read_lock() and __srcu_read_unlock() on systems like x86
> > > > that have NMI-safe this_cpu_inc() operations. This makes the underlying
> > > > __srcu_read_lock_nmisafe() and __srcu_read_unlock_nmisafe() functions
> > > > difficult to test on (for example) x86 systems, allowing bugs to creep in.
> > > >
> > > > This commit therefore creates a FORCE_NEED_SRCU_NMI_SAFE Kconfig that
> > > > forces those underlying functions to be used even on systems where they
> > > > are not needed, thus providing better testing coverage.
> > > >
> > > > Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> > > > Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> > >
> > > Thanks for your patch, which is now commit 536e8b9b80bc7a0a ("srcu:
> > > Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing") in linus/master
> > >
> > > > --- a/kernel/rcu/Kconfig
> > > > +++ b/kernel/rcu/Kconfig
> > > > @@ -65,6 +65,17 @@ config TREE_SRCU
> > > > help
> > > > This option selects the full-fledged version of SRCU.
> > > >
> > > > +config FORCE_NEED_SRCU_NMI_SAFE
> > > > + bool "Force selection of NEED_SRCU_NMI_SAFE"
> > >
> > > What am I supposed to answer here? "n" I guess.
> > > What about distro and allmodconfig kernels?
> >
> > Yes, you should select "n" unless ...
> >
> > > > + depends on !TINY_SRCU
> > > > + select NEED_SRCU_NMI_SAFE
> > > > + default n
> > > > + help
> > > > + This option forces selection of the NEED_SRCU_NMI_SAFE
> > > > + Kconfig option, allowing testing of srcu_read_lock_nmisafe()
> > > > + and srcu_read_unlock_nmisafe() on architectures (like x86)
> > > > + that select the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option.
> > >
> > > Perhaps this should depend on ARCH_HAS_NMI_SAFE_THIS_CPU_OPS?
> >
> > ... you are on a system selecting ARCH_HAS_NMI_SAFE_THIS_CPU_OPS and
>
> So a dependency on ARCH_HAS_NMI_SAFE_THIS_CPU_OPS does make sense,
> doesn't it?
The FORCE_NEED_SRCU_NMI_SAFE has no effect otherwise, so it cannot
hurt. Again, please see below.
Thanx, Paul
> > you would like to test the SRCU setup that needed only by systems that
> > do not select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS.
> >
> > Ah. I forgot to add "depends on RCU_EXPERT".
>
> Yes, that makes sense.
>
> > Apologies, I will fix this. Does the patch show below do the trick?
> >
> > Thanx, Paul
-----------------------------------------------------------------------
commit 2245ef8605a80726548253d885b4cadd97f69f3b
Author: Paul E. McKenney <paulmck@kernel.org>
Date: Tue Mar 25 07:31:45 2025 -0700
srcu: Make FORCE_NEED_SRCU_NMI_SAFE depend on RCU_EXPERT
The FORCE_NEED_SRCU_NMI_SAFE is useful only for those wishing to test
the SRCU code paths that accommodate architectures that do not have
NMI-safe per-CPU operations, that is, those architectures that do not
select the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option. As such, this
is a specialized Kconfig option that is not intended for casual users.
This commit therefore hides it behind the RCU_EXPERT Kconfig option.
Given that this new FORCE_NEED_SRCU_NMI_SAFE Kconfig option has no effect
unless the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option is also selected,
it also depends on this Kconfig option.
[ paulmck: Apply Geert Uytterhoeven feedback. ]
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Closes: https://lore.kernel.org/all/CAMuHMdX6dy9_tmpLkpcnGzxyRbe6qSWYukcPp=H1GzZdyd3qBQ@mail.gmail.com/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index b3f985d41717a..ceaf6594f634c 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -68,6 +68,8 @@ config TREE_SRCU
config FORCE_NEED_SRCU_NMI_SAFE
bool "Force selection of NEED_SRCU_NMI_SAFE"
depends on !TINY_SRCU
+ depends on RCU_EXPERT
+ depends on ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
select NEED_SRCU_NMI_SAFE
default n
help
Hi Paul,
On Tue, 25 Mar 2025 at 16:08, Paul E. McKenney <paulmck@kernel.org> wrote:
> commit 2245ef8605a80726548253d885b4cadd97f69f3b
> Author: Paul E. McKenney <paulmck@kernel.org>
> Date: Tue Mar 25 07:31:45 2025 -0700
>
> srcu: Make FORCE_NEED_SRCU_NMI_SAFE depend on RCU_EXPERT
>
> The FORCE_NEED_SRCU_NMI_SAFE is useful only for those wishing to test
> the SRCU code paths that accommodate architectures that do not have
> NMI-safe per-CPU operations, that is, those architectures that do not
> select the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option. As such, this
> is a specialized Kconfig option that is not intended for casual users.
>
> This commit therefore hides it behind the RCU_EXPERT Kconfig option.
> Given that this new FORCE_NEED_SRCU_NMI_SAFE Kconfig option has no effect
> unless the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option is also selected,
> it also depends on this Kconfig option.
>
> [ paulmck: Apply Geert Uytterhoeven feedback. ]
>
> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Closes: https://lore.kernel.org/all/CAMuHMdX6dy9_tmpLkpcnGzxyRbe6qSWYukcPp=H1GzZdyd3qBQ@mail.gmail.com/
> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
>
> diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
> index b3f985d41717a..ceaf6594f634c 100644
> --- a/kernel/rcu/Kconfig
> +++ b/kernel/rcu/Kconfig
> @@ -68,6 +68,8 @@ config TREE_SRCU
> config FORCE_NEED_SRCU_NMI_SAFE
> bool "Force selection of NEED_SRCU_NMI_SAFE"
> depends on !TINY_SRCU
> + depends on RCU_EXPERT
> + depends on ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
> select NEED_SRCU_NMI_SAFE
> default n
> help
LGTM, so
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
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
On Tue, Mar 25, 2025 at 04:36:23PM +0100, Geert Uytterhoeven wrote: > Hi Paul, > > On Tue, 25 Mar 2025 at 16:08, Paul E. McKenney <paulmck@kernel.org> wrote: > > commit 2245ef8605a80726548253d885b4cadd97f69f3b > > Author: Paul E. McKenney <paulmck@kernel.org> > > Date: Tue Mar 25 07:31:45 2025 -0700 > > > > srcu: Make FORCE_NEED_SRCU_NMI_SAFE depend on RCU_EXPERT > > > > The FORCE_NEED_SRCU_NMI_SAFE is useful only for those wishing to test > > the SRCU code paths that accommodate architectures that do not have > > NMI-safe per-CPU operations, that is, those architectures that do not > > select the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option. As such, this > > is a specialized Kconfig option that is not intended for casual users. > > > > This commit therefore hides it behind the RCU_EXPERT Kconfig option. > > Given that this new FORCE_NEED_SRCU_NMI_SAFE Kconfig option has no effect > > unless the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option is also selected, > > it also depends on this Kconfig option. > > > > [ paulmck: Apply Geert Uytterhoeven feedback. ] > > > > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> > > Closes: https://lore.kernel.org/all/CAMuHMdX6dy9_tmpLkpcnGzxyRbe6qSWYukcPp=H1GzZdyd3qBQ@mail.gmail.com/ > > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > > > > diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig > > index b3f985d41717a..ceaf6594f634c 100644 > > --- a/kernel/rcu/Kconfig > > +++ b/kernel/rcu/Kconfig > > @@ -68,6 +68,8 @@ config TREE_SRCU > > config FORCE_NEED_SRCU_NMI_SAFE > > bool "Force selection of NEED_SRCU_NMI_SAFE" > > depends on !TINY_SRCU > > + depends on RCU_EXPERT > > + depends on ARCH_HAS_NMI_SAFE_THIS_CPU_OPS > > select NEED_SRCU_NMI_SAFE > > default n > > help > > LGTM, so > Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Applied, and thank you very much for both the review and the report! Thanx, Paul
On Tue, Mar 25, 2025 at 08:51:05AM -0700, Paul E. McKenney wrote: > On Tue, Mar 25, 2025 at 04:36:23PM +0100, Geert Uytterhoeven wrote: > > Hi Paul, > > > > On Tue, 25 Mar 2025 at 16:08, Paul E. McKenney <paulmck@kernel.org> wrote: > > > commit 2245ef8605a80726548253d885b4cadd97f69f3b > > > Author: Paul E. McKenney <paulmck@kernel.org> > > > Date: Tue Mar 25 07:31:45 2025 -0700 > > > > > > srcu: Make FORCE_NEED_SRCU_NMI_SAFE depend on RCU_EXPERT > > > > > > The FORCE_NEED_SRCU_NMI_SAFE is useful only for those wishing to test > > > the SRCU code paths that accommodate architectures that do not have > > > NMI-safe per-CPU operations, that is, those architectures that do not > > > select the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option. As such, this > > > is a specialized Kconfig option that is not intended for casual users. > > > > > > This commit therefore hides it behind the RCU_EXPERT Kconfig option. > > > Given that this new FORCE_NEED_SRCU_NMI_SAFE Kconfig option has no effect > > > unless the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option is also selected, > > > it also depends on this Kconfig option. > > > > > > [ paulmck: Apply Geert Uytterhoeven feedback. ] > > > > > > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> > > > Closes: https://lore.kernel.org/all/CAMuHMdX6dy9_tmpLkpcnGzxyRbe6qSWYukcPp=H1GzZdyd3qBQ@mail.gmail.com/ > > > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > > > > > > diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig > > > index b3f985d41717a..ceaf6594f634c 100644 > > > --- a/kernel/rcu/Kconfig > > > +++ b/kernel/rcu/Kconfig > > > @@ -68,6 +68,8 @@ config TREE_SRCU > > > config FORCE_NEED_SRCU_NMI_SAFE > > > bool "Force selection of NEED_SRCU_NMI_SAFE" > > > depends on !TINY_SRCU > > > + depends on RCU_EXPERT > > > + depends on ARCH_HAS_NMI_SAFE_THIS_CPU_OPS > > > select NEED_SRCU_NMI_SAFE > > > default n > > > help > > > > LGTM, so > > Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> > > Applied, and thank you very much for both the review and the report! > Queued for further testing, thank you both! Regards, Boqun > Thanx, Paul
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