From 8c03273a509c88b12c53a9ddf07702f83983e4de Mon Sep 17 00:00:00 2001 From: John Ogness Date: Tue, 20 Aug 2024 08:36:00 +0206 Subject: rcu: Mark emergency sections in rcu stalls Mark emergency sections wherever multiple lines of rcu stall information are generated. In an emergency section, every printk() call will attempt to directly flush to the consoles using the EMERGENCY priority. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Acked-by: Paul E. McKenney Link: https://lore.kernel.org/r/20240820063001.36405-35-john.ogness@linutronix.de Signed-off-by: Petr Mladek --- kernel/rcu/tree_exp.h | 7 +++++++ kernel/rcu/tree_stall.h | 9 +++++++++ 2 files changed, 16 insertions(+) (limited to 'kernel/rcu') diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h index 4acd29d16fdb..f6b35a0585a8 100644 --- a/kernel/rcu/tree_exp.h +++ b/kernel/rcu/tree_exp.h @@ -7,6 +7,7 @@ * Authors: Paul E. McKenney */ +#include #include static void rcu_exp_handler(void *unused); @@ -590,6 +591,9 @@ static void synchronize_rcu_expedited_wait(void) return; if (rcu_stall_is_suppressed()) continue; + + nbcon_cpu_emergency_enter(); + j = jiffies; rcu_stall_notifier_call_chain(RCU_STALL_NOTIFY_EXP, (void *)(j - jiffies_start)); trace_rcu_stall_warning(rcu_state.name, TPS("ExpeditedStall")); @@ -643,6 +647,9 @@ static void synchronize_rcu_expedited_wait(void) rcu_exp_print_detail_task_stall_rnp(rnp); } jiffies_stall = 3 * rcu_exp_jiffies_till_stall_check() + 3; + + nbcon_cpu_emergency_exit(); + panic_on_rcu_stall(); } } diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 4b0e9d7c4c68..b3a6943127bc 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -7,6 +7,7 @@ * Author: Paul E. McKenney */ +#include #include #include @@ -605,6 +606,8 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps) if (rcu_stall_is_suppressed()) return; + nbcon_cpu_emergency_enter(); + /* * OK, time to rat on our buddy... * See Documentation/RCU/stallwarn.rst for info on how to debug @@ -657,6 +660,8 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps) rcu_check_gp_kthread_expired_fqs_timer(); rcu_check_gp_kthread_starvation(); + nbcon_cpu_emergency_exit(); + panic_on_rcu_stall(); rcu_force_quiescent_state(); /* Kick them all. */ @@ -677,6 +682,8 @@ static void print_cpu_stall(unsigned long gps) if (rcu_stall_is_suppressed()) return; + nbcon_cpu_emergency_enter(); + /* * OK, time to rat on ourselves... * See Documentation/RCU/stallwarn.rst for info on how to debug @@ -706,6 +713,8 @@ static void print_cpu_stall(unsigned long gps) jiffies + 3 * rcu_jiffies_till_stall_check() + 3); raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + nbcon_cpu_emergency_exit(); + panic_on_rcu_stall(); /* -- cgit v1.2.3