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-rw-r--r--drivers/tty/sysrq.c18
1 files changed, 12 insertions, 6 deletions
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index b767a64e49d9..7430e87d7352 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -510,9 +510,8 @@ 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_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
@@ -554,7 +553,7 @@ 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();
}
void handle_sysrq(int key)
@@ -1043,16 +1042,23 @@ 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;
}

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