Subject: Re: linux-next: build warning after merge of the akpm tree

From: Vijayanand Jitta <[email-masked]>
Date: Mon, 1 Feb 2021 12:44:51 +0530

On 1/28/2021 2:16 PM, Stephen Rothwell wrote:
> Hi all,
> 
> After merging the akpm tree, today's linux-next build (x86_64
> allmodconfig) produced this warning:
> 
> lib/stackdepot.c: In function 'is_stack_depot_disabled':
> lib/stackdepot.c:154:2: warning: ignoring return value of 'kstrtobool' declared with attribute 'warn_unused_result' [-Wunused-result]
>   154 |  kstrtobool(str, &stack_depot_disable);
>       |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Introduced by commit
> 
>   b9779abb09a8 ("lib: stackdepot: add support to disable stack depot")
> 
> Interestingly, we have 2 declarations of kstrtobool - one in
> linux/kernel.h (which has __must_check) and one in linux/strings.h
> (which doesn't).
> 

I have sent out the fix to lkml, Copied it below for your reference.
Please Feel free to apply or squash it to the original commit.

Thanks,
Vijay

--
From: Vijayanand Jitta <[email-masked]>

fix the below ignoring return value warning for kstrtobool
in is_stack_depot_disabled function.

lib/stackdepot.c: In function 'is_stack_depot_disabled':
lib/stackdepot.c:154:2: warning: ignoring return value of 'kstrtobool'
declared with attribute 'warn_unused_result' [-Wunused-result]

Fixes: b9779abb09a8 ("lib: stackdepot: add support to disable stack depot")
Signed-off-by: Vijayanand Jitta <[email-masked]>
---
 lib/stackdepot.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index cc21116..49f67a0 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -151,8 +151,10 @@ static struct stack_record **stack_table;

 static int __init is_stack_depot_disabled(char *str)
 {
-	kstrtobool(str, &stack_depot_disable);
-	if (stack_depot_disable) {
+	int ret;
+
+	ret = kstrtobool(str, &stack_depot_disable);
+	if (!ret && stack_depot_disable) {
 		pr_info("Stack Depot is disabled\n");
 		stack_table = NULL;
 	}
-- 
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