diff mbox series

[v2,2/3] serial: Move LF -> CRLF replacement from serial console to kdb

Message ID 20241211153955.33518-3-tjarlama@gmail.com
State New
Headers show
Series Add a new command in kgdb for vmcoreinfo | expand

Commit Message

Amal Raj T Dec. 11, 2024, 3:39 p.m. UTC
From: Amal Raj T <amalrajt@meta.com>

The current implementation of `poll_put_char` in the serial console driver
performs LF -> CRLF replacement, which can corrupt binary data. Since kdb
is the only user of `poll_put_char`, this patch moves the LF -> CRLF
replacement logic to kdb.

Link: https://lore.kernel.org/linux-debuggers/Zy093jVKPs9gSVx2@telecaster/

Signed-off-by: Amal Raj T <amalrajt@meta.com>
---
 drivers/tty/serial/serial_core.c | 2 --
 kernel/debug/kdb/kdb_io.c        | 2 ++
 2 files changed, 2 insertions(+), 2 deletions(-)

Comments

Doug Anderson Dec. 13, 2024, 12:55 a.m. UTC | #1
Hi,

On Wed, Dec 11, 2024 at 7:40 AM Amal Raj T <tjarlama@gmail.com> wrote:
>
> From: Amal Raj T <amalrajt@meta.com>
>
> The current implementation of `poll_put_char` in the serial console driver
> performs LF -> CRLF replacement, which can corrupt binary data. Since kdb
> is the only user of `poll_put_char`, this patch moves the LF -> CRLF
> replacement logic to kdb.
>
> Link: https://lore.kernel.org/linux-debuggers/Zy093jVKPs9gSVx2@telecaster/
>
> Signed-off-by: Amal Raj T <amalrajt@meta.com>
> ---
>  drivers/tty/serial/serial_core.c | 2 --
>  kernel/debug/kdb/kdb_io.c        | 2 ++
>  2 files changed, 2 insertions(+), 2 deletions(-)

Looks reasonable. If someone comes out of the woodwork and says that
this breaks them then we can try to figure out a solution as talked
about previously [1]. It would be nice to include a link to the
previous conversation in your comment message...

With the reference to the previous conversation:

Reviewed-by: Douglas Anderson <dianders@chromium.org>

[1] https://lore.kernel.org/r/20241115144933.GB4408@aspen.lan
diff mbox series

Patch

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 74fa02b23772..8e702f3deffb 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2738,8 +2738,6 @@  static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
 	if (!port)
 		return;
 
-	if (ch == '\n')
-		port->ops->poll_put_char(port, '\r');
 	port->ops->poll_put_char(port, ch);
 	uart_port_deref(port);
 }
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 6a77f1c779c4..43a7c8ad741a 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -572,6 +572,8 @@  static void kdb_msg_write(const char *msg, int msg_len)
 	len = msg_len;
 
 	while (len--) {
+		if (*cp == '\n')
+			dbg_io_ops->write_char('\r');
 		dbg_io_ops->write_char(*cp);
 		cp++;
 	}