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path: root/drivers/tty/sysrq.c
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Diffstat (limited to 'drivers/tty/sysrq.c')
-rw-r--r--drivers/tty/sysrq.c29
1 files changed, 19 insertions, 10 deletions
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index ce396ecdf412..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>
@@ -88,7 +89,7 @@ static void sysrq_handle_loglevel(int key)
int i;
i = key - '0';
- console_loglevel = 7;
+ console_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
printk("Loglevel set to %d\n", i);
console_loglevel = i;
}
@@ -343,7 +344,7 @@ static void send_sig_all(int sig)
static void sysrq_handle_term(int key)
{
send_sig_all(SIGTERM);
- console_loglevel = 8;
+ console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
}
static struct sysrq_key_op sysrq_term_op = {
.handler = sysrq_handle_term,
@@ -387,7 +388,7 @@ static struct sysrq_key_op sysrq_thaw_op = {
static void sysrq_handle_kill(int key)
{
send_sig_all(SIGKILL);
- console_loglevel = 8;
+ console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
}
static struct sysrq_key_op sysrq_kill_op = {
.handler = sysrq_handle_kill,
@@ -510,9 +511,9 @@ void __handle_sysrq(int key, bool check_mask)
struct sysrq_key_op *op_p;
int orig_log_level;
int i;
- unsigned long flags;
- spin_lock_irqsave(&sysrq_key_table_lock, flags);
+ rcu_sysrq_start();
+ rcu_read_lock();
/*
* Raise the apparent loglevel to maximum so that the sysrq header
* is shown to provide the user with positive feedback. We do not
@@ -520,7 +521,7 @@ void __handle_sysrq(int key, bool check_mask)
* routing in the consumers of /proc/kmsg.
*/
orig_log_level = console_loglevel;
- console_loglevel = 7;
+ console_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
printk(KERN_INFO "SysRq : ");
op_p = __sysrq_get_key_op(key);
@@ -554,7 +555,8 @@ void __handle_sysrq(int key, bool check_mask)
printk("\n");
console_loglevel = orig_log_level;
}
- spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
+ rcu_read_unlock();
+ rcu_sysrq_end();
}
void handle_sysrq(int key)
@@ -1043,16 +1045,23 @@ static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
struct sysrq_key_op *remove_op_p)
{
int retval;
- unsigned long flags;
- spin_lock_irqsave(&sysrq_key_table_lock, flags);
+ spin_lock(&sysrq_key_table_lock);
if (__sysrq_get_key_op(key) == remove_op_p) {
__sysrq_put_key_op(key, insert_op_p);
retval = 0;
} else {
retval = -1;
}
- spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
+ spin_unlock(&sysrq_key_table_lock);
+
+ /*
+ * A concurrent __handle_sysrq either got the old op or the new op.
+ * Wait for it to go away before returning, so the code for an old
+ * op is not freed (eg. on module unload) while it is in use.
+ */
+ synchronize_rcu();
+
return retval;
}