Thread (19 messages) 19 messages, 3 authors, 2025-03-26

Re: [PATCH rcu 10/11] srcu: Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing

From: Boqun Feng <hidden>
Date: 2025-03-26 05:42:04
Also in: linux-doc, linux-kselftest, lkml, rcu

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:
quoted
Hi Paul,

On Tue, 25 Mar 2025 at 16:08, Paul E. McKenney [off-list ref] wrote:
quoted
commit 2245ef8605a80726548253d885b4cadd97f69f3b
Author: Paul E. McKenney [off-list ref]
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 [off-list ref]
    Closes: https://lore.kernel.org/all/CAMuHMdX6dy9_tmpLkpcnGzxyRbe6qSWYukcPp=H1GzZdyd3qBQ@mail.gmail.com/ (local)
    Signed-off-by: Paul E. McKenney [off-list ref]
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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