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Groups > linux.kernel > #1297583 > unrolled thread

[PATCH] tty/serial: Skip 'NULL' char after console break when sysrq enabled

Started byVijay Kumar <vijay.ac.kumar@oracle.com>
First post2015-12-23 20:00 +0100
Last post2015-12-24 17:50 +0100
Articles 2 — 2 participants

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  [PATCH] tty/serial: Skip 'NULL' char after console break when sysrq enabled Vijay Kumar <vijay.ac.kumar@oracle.com> - 2015-12-23 20:00 +0100
    Re: [PATCH] tty/serial: Skip 'NULL' char after console break when  sysrq enabled David Miller <davem@davemloft.net> - 2015-12-24 17:50 +0100

#1297583 — [PATCH] tty/serial: Skip 'NULL' char after console break when sysrq enabled

FromVijay Kumar <vijay.ac.kumar@oracle.com>
Date2015-12-23 20:00 +0100
Subject[PATCH] tty/serial: Skip 'NULL' char after console break when sysrq enabled
Message-ID<qIWNH-4OT-1@gated-at.bofh.it>
When sysrq is triggered from console, serial driver for SUN hypervisor
console receives a console break and enables the sysrq. It expects a valid
sysrq char following with break. Meanwhile if driver receives 'NULL'
ASCII char then it disables sysrq and sysrq handler will never be invoked.

This fix skips calling uart sysrq handler when 'NULL' is received while
sysrq is enabled.

Signed-off-by: Vijay Kumar <vijay.ac.kumar@oracle.com>
Acked-by: Karl Volz <karl.volz@oracle.com>
---
 drivers/tty/serial/sunhv.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/sunhv.c b/drivers/tty/serial/sunhv.c
index 0640318..163ae5d 100644
--- a/drivers/tty/serial/sunhv.c
+++ b/drivers/tty/serial/sunhv.c
@@ -148,8 +148,10 @@ static int receive_chars_read(struct uart_port *port)
 			uart_handle_dcd_change(port, 1);
 		}
 
-		for (i = 0; i < bytes_read; i++)
-			uart_handle_sysrq_char(port, con_read_page[i]);
+		if (port->sysrq != 0 &&  *con_read_page) {
+			for (i = 0; i < bytes_read; i++)
+				uart_handle_sysrq_char(port, con_read_page[i]);
+		}
 
 		if (port->state == NULL)
 			continue;
-- 
1.7.1

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#1298008 — Re: [PATCH] tty/serial: Skip 'NULL' char after console break when sysrq enabled

FromDavid Miller <davem@davemloft.net>
Date2015-12-24 17:50 +0100
SubjectRe: [PATCH] tty/serial: Skip 'NULL' char after console break when sysrq enabled
Message-ID<qJhfr-GU-3@gated-at.bofh.it>
In reply to#1297583
From: Vijay Kumar <vijay.ac.kumar@oracle.com>
Date: Wed, 23 Dec 2015 10:55:33 -0800

> When sysrq is triggered from console, serial driver for SUN hypervisor
> console receives a console break and enables the sysrq. It expects a valid
> sysrq char following with break. Meanwhile if driver receives 'NULL'
> ASCII char then it disables sysrq and sysrq handler will never be invoked.
> 
> This fix skips calling uart sysrq handler when 'NULL' is received while
> sysrq is enabled.
> 
> Signed-off-by: Vijay Kumar <vijay.ac.kumar@oracle.com>
> Acked-by: Karl Volz <karl.volz@oracle.com>

Applied, thank you.
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