From: Max Filippov <jcmvbkbc@xxxxxxxxx>
This patch has been added to the 4.1 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit 362014c8d9d51d504c167c44ac280169457732be ]
Simulator stdin may be connected to a file, when its end is reached
kernel hangs in infinite loop inside rs_poll, because simc_poll always
signals that descriptor 0 is readable and simc_read always returns 0.
Check simc_read return value and exit loop if it's not positive. Also
don't rewind polling timer if it's zero.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Max Filippov <jcmvbkbc@xxxxxxxxx>
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
arch/xtensa/platforms/iss/console.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/xtensa/platforms/iss/console.c b/arch/xtensa/platforms/iss/console.c
index 70cb408..92d785f 100644
--- a/arch/xtensa/platforms/iss/console.c
+++ b/arch/xtensa/platforms/iss/console.c
@@ -100,21 +100,23 @@ static void rs_poll(unsigned long priv)
{
struct tty_port *port = (struct tty_port *)priv;
int i = 0;
+ int rd = 1;
unsigned char c;
spin_lock(&timer_lock);
while (simc_poll(0)) {
- simc_read(0, &c, 1);
+ rd = simc_read(0, &c, 1);
+ if (rd <= 0)
+ break;
tty_insert_flip_char(port, c, TTY_NORMAL);
i++;
}
if (i)
tty_flip_buffer_push(port);
-
-
- mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
+ if (rd)
+ mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
spin_unlock(&timer_lock);
}
--
2.5.0
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