From c9b12b59e2ea4c3c7cedec7efb071b649652f3a9 Mon Sep 17 00:00:00 2001 From: Sven Schnelle Date: Mon, 6 Dec 2021 11:50:16 +0100 Subject: [PATCH] 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: # 5.12+ Reported-by: Mark Rutland Fixes: 56e62a737028 ("s390: convert to generic entry") Signed-off-by: Sven Schnelle Signed-off-by: Heiko Carstens --- arch/s390/kernel/irq.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/s390/kernel/irq.c b/arch/s390/kernel/irq.c index 0df83ecaa2e0..cb7099682340 100644 --- a/arch/s390/kernel/irq.c +++ b/arch/s390/kernel/irq.c @@ -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);