kevin/linux
1
Fork 0
Code

rcu: Mark emergency sections in rcu stalls

Browse Source 
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 <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20240820063001.36405-35-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
This commit is contained in:
John Ogness 2024-08-20 08:36:00 +02:06 committed by Petr Mladek
parent 4bdfa0d8e9
commit 8c03273a50
2 changed files with 16 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
kernel/rcu/tree_exp.h
View File

@ -7,6 +7,7 @@
* Authors: Paul E. McKenney <paulmck@linux.ibm.com>
*/
#include <linux/console.h>
#include <linux/lockdep.h>
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();
}
}

9
kernel/rcu/tree_stall.h
View File

@ -7,6 +7,7 @@
* Author: Paul E. McKenney <paulmck@linux.ibm.com>
*/
#include <linux/console.h>
#include <linux/kvm_para.h>
#include <linux/rcu_notifier.h>
@ -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();
/*