linux-kernel - [PATCH v2 TSC and clocksource-watchdog updates for v6.12 2/5] clocksource: Fix brown-bag boolean thinko in cs_watchdog

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Message-Id: <20240802154618.4149953-2-paulmck@kernel.org>
Date: Fri,  2 Aug 2024 08:46:15 -0700
From: "Paul E. McKenney" <paulmck@...nel.org>
To: Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>
Cc: "H. Peter Anvin" <hpa@...or.com>,
	John Stultz <jstultz@...gle.com>,
	Stephen Boyd <sboyd@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Feng Tang <feng.tang@...el.com>,
	Waiman Long <longman@...hat.com>,
	Neeraj Upadhyay <Neeraj.Upadhyay@....com>,
	x86@...nel.org,
	kernel-team@...a.com,
	linux-kernel@...r.kernel.org,
	"Paul E. McKenney" <paulmck@...nel.org>
Subject: [PATCH v2 TSC and clocksource-watchdog updates for v6.12 2/5]  clocksource: Fix brown-bag boolean thinko in cs_watchdog_read()

The current "nretries > 1 || nretries >= max_retries" check in
cs_watchdog_read() will always evaluate to true, and thus pr_warn(), if
nretries is greater than 1.  The intent is instead to never warn on the
first try, but otherwise warn if the successful retry was the last retry.

Therefore, change that "||" to "&&".

Reported-by: Borislav Petkov <bp@...en8.de>
Fixes: db3a34e17433 ("clocksource: Retry clock read if long delays detected")
Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
---
 kernel/time/clocksource.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 9ca4e8d2a70f8..581cdbb538448 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -253,7 +253,7 @@ static enum wd_read_status cs_watchdog_read(struct clocksource *cs, u64 *csnow,
 
 		wd_delay = cycles_to_nsec_safe(watchdog, *wdnow, wd_end);
 		if (wd_delay <= WATCHDOG_MAX_SKEW) {
-			if (nretries > 1 || nretries >= max_retries) {
+			if (nretries > 1 && nretries >= max_retries) {
 				pr_warn("timekeeping watchdog on CPU%d: %s retried %d times before success\n",
 					smp_processor_id(), watchdog->name, nretries);
 			}
-- 
2.40.1