[PATCH] [PATCH]Fixed: line break of pr_cont not take effect in linux-rt

[PATCH] [PATCH]Fixed: line break of pr_cont not take effect in linux-rt

[root]

From: 汪勇10269566 <wang.yong12@zte.com.cn>

Line break of pr_cont not take effect.
Use several pr_cont to print continuous paragraph, it is expected to
have line break when line ends up with  '\n', however the paragraph
does not have line break
-printk_kthread_func will not print info before log_store insert msg
 into printk_rb, and pr_cont calls cont_add to keep data in buffer.
 cont_add only when the following conditions are met insert msg to
 printk_rb
 1.cpu != c->cpu_owner || !(flags & LOG_CONT)
 2.c->len + len > sizeof(c->buf)

Signed-off-by: 汪勇10269566 <wang.yong12@zte.com.cn>
---
 kernel/printk/printk.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 0605a74..d898f50 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1871,6 +1871,7 @@ static void cont_add(int ctx, int cpu, u32 caller_id, int facility, int level,
 	// but later continuations can add a newline.
 	if (flags & LOG_NEWLINE) {
 		c->flags |= LOG_NEWLINE;
+		cont_flush(ctx);
 	}
 }
 
-- 
2.15.2

Re: [PATCH] [PATCH]Fixed: line break of pr_cont not take effect in linux-rt

[Petr Mladek]

On Thu 2020-05-21 09:37:44, root wrote:
> From: 汪勇10269566 <wang.yong12@zte.com.cn>
> 
> Line break of pr_cont not take effect.
> Use several pr_cont to print continuous paragraph, it is expected to
> have line break when line ends up with  '\n', however the paragraph
> does not have line break
> -printk_kthread_func will not print info before log_store insert msg
>  into printk_rb, and pr_cont calls cont_add to keep data in buffer.
>  cont_add only when the following conditions are met insert msg to
>  printk_rb
>  1.cpu != c->cpu_owner || !(flags & LOG_CONT)
>  2.c->len + len > sizeof(c->buf)
> 
> Signed-off-by: 汪勇10269566 <wang.yong12@zte.com.cn>
> ---
>  kernel/printk/printk.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index 0605a74..d898f50 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -1871,6 +1871,7 @@ static void cont_add(int ctx, int cpu, u32 caller_id, int facility, int level,
>  	// but later continuations can add a newline.
>  	if (flags & LOG_NEWLINE) {
>  		c->flags |= LOG_NEWLINE;
> +		cont_flush(ctx);

What kernel sources is this patch against, please?

The console_flush() call is in the current Linus' tree. It does not
have any parameter there. And there is no printk_kthread_func.

Is this against RT patchset?

Best Regards,
Petr