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From: Arnd Bergmann <arnd@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>, Waiman Long <longman@redhat.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	"Steven Rostedt (VMware)" <rostedt@goodmis.org>,
	linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com
Subject: [PATCH] lockdep: address clang -Wformat warning printing for %hd
Date: Mon, 22 Mar 2021 12:55:25 +0100	[thread overview]
Message-ID: <20210322115531.3987555-1-arnd@kernel.org> (raw)

From: Arnd Bergmann <arnd@arndb.de>

Clang doesn't like format strings that truncate a 32-bit
value to something shorter:

kernel/locking/lockdep.c:709:4: error: format specifies type 'short' but the argument has type 'int' [-Werror,-Wformat]

In this case, the warning is a slightly questionable, as it could realize
that both class->wait_type_outer and class->wait_type_inner are in fact
8-bit struct members, even though the result of the ?: operator becomes an
'int'.

However, there is really no point in printing the number as a 16-bit
'short' rather than either an 8-bit or 32-bit number, so just change
it to a normal %d.

Fixes: de8f5e4f2dc1 ("lockdep: Introduce wait-type checks")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 kernel/locking/lockdep.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 70bf3e48eae3..bb3b0bc6ee17 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -705,7 +705,7 @@ static void print_lock_name(struct lock_class *class)
 
 	printk(KERN_CONT " (");
 	__print_lock_name(class);
-	printk(KERN_CONT "){%s}-{%hd:%hd}", usage,
+	printk(KERN_CONT "){%s}-{%d:%d}", usage,
 			class->wait_type_outer ?: class->wait_type_inner,
 			class->wait_type_inner);
 }
-- 
2.29.2


             reply	other threads:[~2021-03-22 11:56 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-22 11:55 Arnd Bergmann [this message]
2021-03-22 21:11 ` [tip: perf/urgent] lockdep: Address clang -Wformat warning printing for %hd tip-bot2 for Arnd Bergmann
2021-03-29 18:25 ` [PATCH] lockdep: address " Nick Desaulniers

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