LKML Archive on lore.kernel.org
 help / color / Atom feed
From: John Stultz <john.stultz@linaro.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: John Stultz <john.stultz@linaro.org>,
	Prarit Bhargava <prarit@redhat.com>,
	Richard Cochran <richardcochran@gmail.com>,
	Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: [RFC][PATCH 1/5] clocksource: Fix abs() usage w/ 64bit values
Date: Mon, 14 Sep 2015 18:05:20 -0700
Message-ID: <1442279124-7309-2-git-send-email-john.stultz@linaro.org> (raw)
In-Reply-To: <1442279124-7309-1-git-send-email-john.stultz@linaro.org>

This patch fixes one cases where abs() was being used with 64-bit
nanosecond values, where the result may be capped at 32-bits.

This potentially could cause watchdog false negatives on 32-bit
systems, so this patch addresses the issue by using abs64().

Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.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 841b72f..3a38775 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -217,7 +217,7 @@ static void clocksource_watchdog(unsigned long data)
 			continue;
 
 		/* Check the deviation from the watchdog clocksource. */
-		if ((abs(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD)) {
+		if (abs64(cs_nsec - wd_nsec) > WATCHDOG_THRESHOLD) {
 			pr_warn("timekeeping watchdog: Marking clocksource '%s' as unstable because the skew is too large:\n",
 				cs->name);
 			pr_warn("                      '%s' wd_now: %llx wd_last: %llx mask: %llx\n",
-- 
1.9.1


  reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-15  1:05 [RFC][PATCH 0/5] Fixes for abs() usage on " John Stultz
2015-09-15  1:05 ` John Stultz [this message]
2015-10-02 20:57   ` [tip:timers/urgent] clocksource: Fix abs() usage w/ " tip-bot for John Stultz
2015-09-15  1:05 ` [RFC][PATCH 2/5] time: Fix abs() usage with 64-bit values John Stultz
2015-09-15  1:05 ` [RFC][PATCH 3/5] ext4: Fix abs() usage in ext4_mb_check_group_pa John Stultz
2015-09-15  1:05 ` [RFC][PATCH 4/5] percpu: Fix abs() usage in percpu_counter_compare() John Stultz
2015-09-15  1:05 ` [RFC][PATCH 5/5] abs(): Provide build error on passing 64bit value to abs() John Stultz
2015-09-15  5:22   ` Ingo Molnar
2015-09-15 23:52     ` Linus Torvalds
2015-09-16 12:57       ` [PATCH] kernel.h: make abs() work with 64-bit types Michal Nazarewicz
2015-09-18  3:12         ` John Stultz
2015-09-15  1:49 ` [RFC][PATCH 0/5] Fixes for abs() usage on 64bit values Tejun Heo
2015-09-15  3:27   ` John Stultz
2015-09-15  3:46     ` Tejun Heo
2015-09-15 12:09       ` Jeff Epler
2015-09-15 21:21       ` Andrew Morton
2015-09-15 22:54         ` Michal Nazarewicz
2015-09-15  5:20     ` Ingo Molnar
2015-09-15 23:43       ` Linus Torvalds

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1442279124-7309-2-git-send-email-john.stultz@linaro.org \
    --to=john.stultz@linaro.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@kernel.org \
    --cc=prarit@redhat.com \
    --cc=richardcochran@gmail.com \
    --cc=tglx@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git
	git clone --mirror https://lore.kernel.org/lkml/10 lkml/git/10.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git