[coreboot-gerrit] Change in coreboot[master]: console/printk.c: Prevent recursion in print functions

[Angel Pons (Code Review)]

Angel Pons has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/49942 )

Change subject: console/printk.c: Prevent recursion in print functions
......................................................................

console/printk.c: Prevent recursion in print functions

Exit early if calling a print function from within another print
function. Otherwise, infinite recursion can and will happen.

Change-Id: I742e4087bffa64897e9ffa47531d37e42fb2c63e
Signed-off-by: Angel Pons 
---
M src/console/printk.c
1 file changed, 17 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/42/49942/1

diff --git a/src/console/printk.c b/src/console/printk.c
index 85d9bfb..8822009c 100644
--- a/src/console/printk.c
+++ b/src/console/printk.c
@@ -19,6 +19,9 @@
 static struct mono_time mt_start, mt_stop;
 static long console_usecs;

+/* Prevent recursion in print functions */
+static int recursion_depth;
+
 static void console_time_run(void)
 {
    if (TRACK_CONSOLE_TIME && boot_cpu())
@@ -54,9 +57,16 @@

void do_putchar(unsigned char byte)
 {
+	if (recursion_depth)
+		return;
+
+	recursion_depth++;
+
    console_time_run();
    console_tx_byte(byte);
    console_time_stop();
+
+	recursion_depth--;
 }

static void wrap_putchar(unsigned char byte, void *data)
@@ -80,6 +90,11 @@
    if (log_this < CONSOLE_LOG_FAST)
    	return 0;

+	if (recursion_depth)
+		return 0;
+
+	recursion_depth++;
+
    spin_lock(&console_lock);

console_time_run();
@@ -95,6 +110,8 @@

spin_unlock(&console_lock);

+	recursion_depth--;
+
    return i;
 }