This is a note to let you know that I've just added the patch titled
s390/entry: fix duplicate tracking of irq nesting level
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
s390-entry-fix-duplicate-tracking-of-irq-nesting-level.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c9b12b59e2ea4c3c7cedec7efb071b649652f3a9 Mon Sep 17 00:00:00 2001
From: Sven Schnelle <svens@xxxxxxxxxxxxx>
Date: Mon, 6 Dec 2021 11:50:16 +0100
Subject: s390/entry: fix duplicate tracking of irq nesting level
From: Sven Schnelle <svens@xxxxxxxxxxxxx>
commit c9b12b59e2ea4c3c7cedec7efb071b649652f3a9 upstream.
In the current code, when exiting from idle, rcu_irq_enter() is
called twice during irq entry:
irq_entry_enter()-> rcu_irq_enter()
irq_enter() -> rcu_irq_enter()
This may lead to wrong results from rcu_is_cpu_rrupt_from_idle()
because of a wrong dynticks nmi nesting count. Fix this by only
calling irq_enter_rcu().
Cc: <stable@xxxxxxxxxxxxxxx> # 5.12+
Reported-by: Mark Rutland <mark.rutland@xxxxxxx>
Fixes: 56e62a737028 ("s390: convert to generic entry")
Signed-off-by: Sven Schnelle <svens@xxxxxxxxxxxxx>
Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/kernel/irq.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
--- a/arch/s390/kernel/irq.c
+++ b/arch/s390/kernel/irq.c
@@ -138,7 +138,7 @@ void noinstr do_io_irq(struct pt_regs *r
struct pt_regs *old_regs = set_irq_regs(regs);
int from_idle;
- irq_enter();
+ irq_enter_rcu();
if (user_mode(regs))
update_timer_sys();
@@ -155,7 +155,8 @@ void noinstr do_io_irq(struct pt_regs *r
do_irq_async(regs, IO_INTERRUPT);
} while (MACHINE_IS_LPAR && irq_pending(regs));
- irq_exit();
+ irq_exit_rcu();
+
set_irq_regs(old_regs);
irqentry_exit(regs, state);
@@ -169,7 +170,7 @@ void noinstr do_ext_irq(struct pt_regs *
struct pt_regs *old_regs = set_irq_regs(regs);
int from_idle;
- irq_enter();
+ irq_enter_rcu();
if (user_mode(regs))
update_timer_sys();
@@ -184,7 +185,7 @@ void noinstr do_ext_irq(struct pt_regs *
do_irq_async(regs, EXT_INTERRUPT);
- irq_exit();
+ irq_exit_rcu();
set_irq_regs(old_regs);
irqentry_exit(regs, state);
Patches currently in stable-queue which might be from svens@xxxxxxxxxxxxx are
queue-5.15/s390-entry-fix-duplicate-tracking-of-irq-nesting-level.patch
