* [PATCH v2] tty: Fix lookahead_buf crash with serdev
@ 2022-08-18 11:50 Vincent Whitchurch
2022-08-18 12:00 ` Ilpo Järvinen
0 siblings, 1 reply; 2+ messages in thread
From: Vincent Whitchurch @ 2022-08-18 11:50 UTC (permalink / raw)
To: Greg Kroah-Hartman, Jiri Slaby
Cc: kernel, Vincent Whitchurch, Andy Shevchenko, Ilpo Järvinen,
linux-kernel
Do not follow a NULL pointer if the tty_port_client_operations does not
implement the ->lookahead_buf() callback, which is the case with
serdev's ttyport.
Fixes: 6bb6fa6908ebd3 ("tty: Implement lookahead to process XON/XOFF timely")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
---
Notes:
v2: Move more stuff into if block.
drivers/tty/tty_buffer.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 9fdecc795b6b..5e287dedce01 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -470,7 +470,6 @@ static void lookahead_bufs(struct tty_port *port, struct tty_buffer *head)
while (head) {
struct tty_buffer *next;
- unsigned char *p, *f = NULL;
unsigned int count;
/*
@@ -489,11 +488,16 @@ static void lookahead_bufs(struct tty_port *port, struct tty_buffer *head)
continue;
}
- p = char_buf_ptr(head, head->lookahead);
- if (~head->flags & TTYB_NORMAL)
- f = flag_buf_ptr(head, head->lookahead);
+ if (port->client_ops->lookahead_buf) {
+ unsigned char *p, *f = NULL;
+
+ p = char_buf_ptr(head, head->lookahead);
+ if (~head->flags & TTYB_NORMAL)
+ f = flag_buf_ptr(head, head->lookahead);
+
+ port->client_ops->lookahead_buf(port, p, f, count);
+ }
- port->client_ops->lookahead_buf(port, p, f, count);
head->lookahead += count;
}
}
--
2.34.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] tty: Fix lookahead_buf crash with serdev
2022-08-18 11:50 [PATCH v2] tty: Fix lookahead_buf crash with serdev Vincent Whitchurch
@ 2022-08-18 12:00 ` Ilpo Järvinen
0 siblings, 0 replies; 2+ messages in thread
From: Ilpo Järvinen @ 2022-08-18 12:00 UTC (permalink / raw)
To: Vincent Whitchurch
Cc: Greg Kroah-Hartman, Jiri Slaby, kernel, Andy Shevchenko, LKML
[-- Attachment #1: Type: text/plain, Size: 1635 bytes --]
On Thu, 18 Aug 2022, Vincent Whitchurch wrote:
> Do not follow a NULL pointer if the tty_port_client_operations does not
> implement the ->lookahead_buf() callback, which is the case with
> serdev's ttyport.
>
> Fixes: 6bb6fa6908ebd3 ("tty: Implement lookahead to process XON/XOFF timely")
> Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
--
i.
> ---
>
> Notes:
> v2: Move more stuff into if block.
>
> drivers/tty/tty_buffer.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
> index 9fdecc795b6b..5e287dedce01 100644
> --- a/drivers/tty/tty_buffer.c
> +++ b/drivers/tty/tty_buffer.c
> @@ -470,7 +470,6 @@ static void lookahead_bufs(struct tty_port *port, struct tty_buffer *head)
>
> while (head) {
> struct tty_buffer *next;
> - unsigned char *p, *f = NULL;
> unsigned int count;
>
> /*
> @@ -489,11 +488,16 @@ static void lookahead_bufs(struct tty_port *port, struct tty_buffer *head)
> continue;
> }
>
> - p = char_buf_ptr(head, head->lookahead);
> - if (~head->flags & TTYB_NORMAL)
> - f = flag_buf_ptr(head, head->lookahead);
> + if (port->client_ops->lookahead_buf) {
> + unsigned char *p, *f = NULL;
> +
> + p = char_buf_ptr(head, head->lookahead);
> + if (~head->flags & TTYB_NORMAL)
> + f = flag_buf_ptr(head, head->lookahead);
> +
> + port->client_ops->lookahead_buf(port, p, f, count);
> + }
>
> - port->client_ops->lookahead_buf(port, p, f, count);
> head->lookahead += count;
> }
> }
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-08-18 11:50 [PATCH v2] tty: Fix lookahead_buf crash with serdev Vincent Whitchurch
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