sysrq,rcu: suppress RCU stall warnings while sysrq runs
Some sysrq handlers can run for a long time, because they dump a lot of
data onto a serial console. Having RCU stall warnings pop up in the
middle of them only makes the problem worse.
This patch temporarily disables RCU stall warnings while a sysrq request
is handled.
Signed-off-by: Rik van Riel <riel@redhat.com>
Suggested-by: Paul McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Madper Xie <cxie@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 7430e87..454b658 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -46,6 +46,7 @@
#include <linux/jiffies.h>
#include <linux/syscalls.h>
#include <linux/of.h>
+#include <linux/rcupdate.h>
#include <asm/ptrace.h>
#include <asm/irq_regs.h>
@@ -511,6 +512,7 @@
int orig_log_level;
int i;
+ rcu_sysrq_start();
rcu_read_lock();
/*
* Raise the apparent loglevel to maximum so that the sysrq header
@@ -554,6 +556,7 @@
console_loglevel = orig_log_level;
}
rcu_read_unlock();
+ rcu_sysrq_end();
}
void handle_sysrq(int key)
