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From: Kees Cook <keescook@chromium.org>
To: kernel-hardening@lists.openwall.com
Cc: Kees Cook <keescook@chromium.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Rik van Riel <riel@redhat.com>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Jakub Kicinski <jakub.kicinski@netronome.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Dmitry Vyukov <dvyukov@google.com>,
	Olof Johansson <olof@lixom.net>,
	Peter Zijlstra <peterz@infradead.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 2/6] bug: Improve unlikely() in data corruption check
Date: Mon,  6 Mar 2017 11:09:42 -0800	[thread overview]
Message-ID: <1488827386-87193-3-git-send-email-keescook@chromium.org> (raw)
In-Reply-To: <1488827386-87193-1-git-send-email-keescook@chromium.org>

This improves the compiler branch-hinting used in CHECK_DATA_CORRUPTION(),
similar to how it is done in WARN_ON() and friends.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 include/linux/bug.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/bug.h b/include/linux/bug.h
index 5828489309bb..5ef65dc2ed8b 100644
--- a/include/linux/bug.h
+++ b/include/linux/bug.h
@@ -129,15 +129,15 @@ static inline enum bug_trap_type report_bug(unsigned long bug_addr,
 static inline __must_check bool check_data_corruption(bool v) { return v; }
 #define CHECK_DATA_CORRUPTION(condition, fmt, ...)			 \
 	check_data_corruption(({					 \
-		bool corruption = unlikely(condition);			 \
-		if (corruption) {					 \
+		bool corruption = !!(condition);			 \
+		if (unlikely(corruption)) {				 \
 			if (IS_ENABLED(CONFIG_BUG_ON_DATA_CORRUPTION)) { \
 				pr_err(fmt, ##__VA_ARGS__);		 \
 				BUG();					 \
 			} else						 \
 				WARN(1, fmt, ##__VA_ARGS__);		 \
 		}							 \
-		corruption;						 \
+		unlikely(corruption);					 \
 	}))
 
 #endif	/* _LINUX_BUG_H */
-- 
2.7.4

  parent reply	other threads:[~2017-03-06 19:10 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-06 19:09 [PATCH 0/6] bug: further enhance use of BUG_ON_DATA_CORRUPTION Kees Cook
2017-03-06 19:09 ` [PATCH 1/6] bug: Clarify help text for BUG_ON_DATA_CORRUPTION Kees Cook
2017-03-06 19:09 ` Kees Cook [this message]
2017-03-06 19:09 ` [PATCH 3/6] bug: Enable DEBUG_CREDENTIALS under BUG_ON_DATA_CORRUPTION Kees Cook
2017-03-06 19:09 ` [PATCH 4/6] bug: Enable DEBUG_SG " Kees Cook
2017-03-06 19:09 ` [PATCH 5/6] notifiers: Use CHECK_DATA_CORRUPTION() on checks Kees Cook
2017-03-22 19:29   ` Kees Cook
2017-03-22 19:32     ` Arjan van de Ven
2017-03-22 19:55       ` Kees Cook
2017-03-06 19:09 ` [PATCH 6/6] refcount: Check bad states with CHECK_DATA_CORRUPTION Kees Cook
2017-03-22 19:30   ` Kees Cook

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