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authorRik van Riel <riel@redhat.com>2014-06-06 14:38:14 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-06 16:08:17 -0700
commit722773afd83209d4088d30946bc274f547528a0b (patch)
tree991d1315b8345909e9d9fae4f881b168b4f48944
parent984d74a72076a12b400339973e8c98fd2fcd90e5 (diff)
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>
-rw-r--r--drivers/tty/sysrq.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 7430e87d7352..454b65898e2c 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 @@ 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)

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