[v5] Some bug fixes and cleanups related to kexec

[PATCH v5 3/3] x86/kexec: use pr_err() instead of pr_debug() when an error occurs

Posted by Yuntao Wang 2 years ago

When an error is detected, use pr_err() instead of pr_debug() to output
log message.

In addition, remove the unnecessary return from set_page_address().

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
---
 arch/x86/kernel/kexec-bzimage64.c | 2 +-
 mm/highmem.c                      | 2 --
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index a61c12c01270..472a45dbc79a 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -424,7 +424,7 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
 	 * command line. Make sure it does not overflow
 	 */
 	if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
-		pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
+		pr_err("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
 		return ERR_PTR(-EINVAL);
 	}
 
diff --git a/mm/highmem.c b/mm/highmem.c
index e19269093a93..bd48ba445dd4 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -799,8 +799,6 @@ void set_page_address(struct page *page, void *virtual)
 		}
 		spin_unlock_irqrestore(&pas->lock, flags);
 	}
-
-	return;
 }
 
 void __init page_address_init(void)
-- 
2.43.0

Re: [PATCH v5 3/3] x86/kexec: use pr_err() instead of pr_debug() when an error occurs

Posted by Andrew Morton 2 years ago

On Sun, 17 Dec 2023 11:35:28 +0800 Yuntao Wang <ytcoode@gmail.com> wrote:

> When an error is detected, use pr_err() instead of pr_debug() to output
> log message.
> 
> In addition, remove the unnecessary return from set_page_address().
> 
> ...
>
> --- a/arch/x86/kernel/kexec-bzimage64.c
> +++ b/arch/x86/kernel/kexec-bzimage64.c
> @@ -424,7 +424,7 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
>  	 * command line. Make sure it does not overflow
>  	 */
>  	if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
> -		pr_debug("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
> +		pr_err("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
>  		return ERR_PTR(-EINVAL);
>  	}

https://lkml.kernel.org/r/20231213055747.61826-4-bhe@redhat.com has
already changed this to call kexec_dprintk().  I'll skip this patch.

[PATCH] x86/kexec: use pr_err() instead of kexec_dprintk() when an error occurs

Posted by Yuntao Wang 1 year, 12 months ago

When an error is detected, use pr_err() instead of kexec_dprintk() to
output log message.

In addition, remove the unnecessary return from set_page_address().

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
---
 arch/x86/kernel/kexec-bzimage64.c | 2 +-
 mm/highmem.c                      | 2 --
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index e9ae0eac6bf9..4a77d5dd4bce 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -429,7 +429,7 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
 	 * command line. Make sure it does not overflow
 	 */
 	if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
-		kexec_dprintk("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
+		pr_err("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
 		return ERR_PTR(-EINVAL);
 	}
 
diff --git a/mm/highmem.c b/mm/highmem.c
index e19269093a93..bd48ba445dd4 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -799,8 +799,6 @@ void set_page_address(struct page *page, void *virtual)
 		}
 		spin_unlock_irqrestore(&pas->lock, flags);
 	}
-
-	return;
 }
 
 void __init page_address_init(void)
-- 
2.43.0

Re: [PATCH] x86/kexec: use pr_err() instead of kexec_dprintk() when an error occurs

Posted by Andrew Morton 1 year, 12 months ago

On Tue, 19 Dec 2023 15:29:01 +0800 Yuntao Wang <ytcoode@gmail.com> wrote:

> When an error is detected, use pr_err() instead of kexec_dprintk() to
> output log message.
>
> In addition, remove the unnecessary return from set_page_address().

The above describes what the code does, which is already quite clear
from looking at the code.

Please write changelogs and code comments which describe *why* the code
does something, rather than *what* it does.

>
>
> --- a/arch/x86/kernel/kexec-bzimage64.c
> +++ b/arch/x86/kernel/kexec-bzimage64.c
> @@ -429,7 +429,7 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
>  	 * command line. Make sure it does not overflow
>  	 */
>  	if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
> -		kexec_dprintk("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
> +		pr_err("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");

ie, what are the reasons for this change?

>  		return ERR_PTR(-EINVAL);
>  	}
>  
> diff --git a/mm/highmem.c b/mm/highmem.c
> index e19269093a93..bd48ba445dd4 100644
> --- a/mm/highmem.c
> +++ b/mm/highmem.c
> @@ -799,8 +799,6 @@ void set_page_address(struct page *page, void *virtual)
>  		}
>  		spin_unlock_irqrestore(&pas->lock, flags);
>  	}
> -
> -	return;
>  }
>  
>  void __init page_address_init(void)
> -- 
> 2.43.0

[PATCH v2] x86/kexec: use pr_err() instead of kexec_dprintk() when an error occurs

Posted by Yuntao Wang 1 year, 12 months ago

When detecting an error, the current code uses kexec_dprintk() to output
log message. This is not quite appropriate as kexec_dprintk() is mainly
used for outputting debugging messages, rather than error messages.

Replace kexec_dprintk() with pr_err(). This also makes the output method
for this error log align with the output method for other error logs in
this function.

Additionally, the last return statement in set_page_address() is
unnecessary, remove it.

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
---
v1 -> v2: Rewrite changelogs

 arch/x86/kernel/kexec-bzimage64.c | 2 +-
 mm/highmem.c                      | 2 --
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index e9ae0eac6bf9..4a77d5dd4bce 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -429,7 +429,7 @@ static void *bzImage64_load(struct kimage *image, char *kernel,
 	 * command line. Make sure it does not overflow
 	 */
 	if (cmdline_len + MAX_ELFCOREHDR_STR_LEN > header->cmdline_size) {
-		kexec_dprintk("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
+		pr_err("Appending elfcorehdr=<addr> to command line exceeds maximum allowed length\n");
 		return ERR_PTR(-EINVAL);
 	}
 
diff --git a/mm/highmem.c b/mm/highmem.c
index e19269093a93..bd48ba445dd4 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -799,8 +799,6 @@ void set_page_address(struct page *page, void *virtual)
 		}
 		spin_unlock_irqrestore(&pas->lock, flags);
 	}
-
-	return;
 }
 
 void __init page_address_init(void)
-- 
2.43.0