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s390/entry: fix duplicate tracking of irq nesting level 

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@vger.kernel.org> # 5.12+
Reported-by: Mark Rutland <mark.rutland@arm.com>
Fixes: 56e62a7370 ("s390: convert to generic entry")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Sven Schnelle 2021-12-06 11:50:16 +01:00 committed by Heiko Carstens
parent 5dcf0c3084
commit c9b12b59e2
1 changed files with 5 additions and 4 deletions
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9
arch/s390/kernel/irq.c
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@ -138,7 +138,7 @@ void noinstr do_io_irq(struct pt_regs *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();
@ -158,7 +158,8 @@ void noinstr do_io_irq(struct pt_regs *regs)
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);
@ -172,7 +173,7 @@ void noinstr do_ext_irq(struct pt_regs *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();
@ -190,7 +191,7 @@ void noinstr do_ext_irq(struct pt_regs *regs)
do_irq_async(regs, EXT_INTERRUPT);
irq_exit();
irq_exit_rcu();
set_irq_regs(old_regs);
irqentry_exit(regs, state);