linux-kernel - [tip: timers/urgent] clocksource: Fix brown-bag boolean thinko in cs_watchdog

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Message-ID: <172260979799.2215.16859702418802740077.tip-bot2@tip-bot2>
Date: Fri, 02 Aug 2024 14:43:17 -0000
From: "tip-bot2 for Paul E. McKenney" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Borislav Petkov <bp@...en8.de>, "Paul E. McKenney" <paulmck@...nel.org>,
 Thomas Gleixner <tglx@...utronix.de>, stable@...r.kernel.org, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: timers/urgent] clocksource: Fix brown-bag boolean thinko in
 cs_watchdog_read()

The following commit has been merged into the timers/urgent branch of tip:

Commit-ID:     305c821c3006c1f201eb85bcfb44a35930f54a71
Gitweb:        https://git.kernel.org/tip/305c821c3006c1f201eb85bcfb44a35930f54a71
Author:        Paul E. McKenney <paulmck@...nel.org>
AuthorDate:    Thu, 01 Aug 2024 17:16:36 -07:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Fri, 02 Aug 2024 16:34:26 +02:00

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 "&&".

Fixes: db3a34e17433 ("clocksource: Retry clock read if long delays detected")
Reported-by: Borislav Petkov <bp@...en8.de>
Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: stable@...r.kernel.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 d25ba49..d0538a7 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -246,7 +246,7 @@ 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);
 			}