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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>
hifive-unleashed-5.1
Rik van Riel 2014-06-06 14:38:14 -07:00 committed by Linus Torvalds
parent 984d74a720
commit 722773afd8
1 changed files with 3 additions and 0 deletions
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3
drivers/tty/sysrq.c
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@ -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 @@ void __handle_sysrq(int key, bool check_mask)
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 @@ void __handle_sysrq(int key, bool check_mask)
console_loglevel = orig_log_level;
}
rcu_read_unlock();
rcu_sysrq_end();
}
void handle_sysrq(int key)