Thread (15 messages) 15 messages, 4 authors, 2014-09-23
STALE4286d
Revisions (3)
  1. rfc [diff vs current]
  2. rfc [diff vs current]
  3. v3 current

[PATCH 2/4] tty: omap-serial: prevent division by zero

From: Frans Klaver <hidden>
Date: 2014-09-15 14:06:12
Also in: linux-devicetree, linux-omap, linux-serial, lkml
Subsystem: the rest, tty layer and serial drivers · Maintainers: Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby

If the chosen baud rate is large enough (e.g. 3.5 megabaud), the
calculated n values in calculate_baud_abs_diff may become 0. This causes
a division by zero when calculating the difference between calculated
and desired baud rates. To prevent this, cap n on 1.

Signed-off-by: Frans Klaver <redacted>
---
 drivers/tty/serial/omap-serial.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index ae935ce..7d3f557 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -246,8 +246,12 @@ static inline int calculate_baud_abs_diff(struct uart_port *port,
 				unsigned int baud, unsigned int mode)
 {
 	unsigned int n = port->uartclk / (mode * baud);
-	int abs_diff = baud - (port->uartclk / (mode * n));
+	int abs_diff;
 
+	if (n == 0)
+		n = 1;
+
+	abs_diff = baud - (port->uartclk / (mode * n));
 	if (abs_diff < 0)
 		abs_diff = -abs_diff;
 
-- 
2.1.0
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help