The patch titled
Subject: watchdog: Handle the ENODEV failure case of lockup_detector_delay_init() separately
has been added to the -mm mm-nonmm-unstable branch. Its filename is
watchdog-handle-the-enodev-failure-case-of-lockup_detector_delay_init-separately.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/watchdog-handle-the-enodev-failure-case-of-lockup_detector_delay_init-separately.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Waiman Long <longman@xxxxxxxxxx>
Subject: watchdog: Handle the ENODEV failure case of lockup_detector_delay_init() separately
Date: Fri, 2 Aug 2024 11:16:21 -0400
When watchdog_hardlockup_probe() is being called by
lockup_detector_delay_init(), an error return of -ENODEV will happen
for the arm64 arch when arch_perf_nmi_is_available() returns false. This
means that NMI is not usable by the hard lockup detector and so has to
be disabled. This can be considered a deficiency in that particular
arm64 chip, but there is nothing we can do about it. That also means
the following error will always be reported when the kernel boot up.
watchdog: Delayed init of the lockup detector failed: -19
The word "failed" itself has a connotation that there is something
wrong with the kernel which is not really the case here. Handle this
special ENODEV case separately and explain the reason behind disabling
hard lockup detector without causing anxiety for those users who read
the above message and wonder about it.
Link: https://lkml.kernel.org/r/20240802151621.617244-1-longman@xxxxxxxxxx
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
Cc: Douglas Anderson <dianders@xxxxxxxxxxxx>
Cc: Joel Granados <j.granados@xxxxxxxxxxx>
Cc: Li Zhe <lizhe.67@xxxxxxxxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Thomas WeiÃ?schuh <linux@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/watchdog.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/kernel/watchdog.c~watchdog-handle-the-enodev-failure-case-of-lockup_detector_delay_init-separately
+++ a/kernel/watchdog.c
@@ -1203,7 +1203,10 @@ static void __init lockup_detector_delay
ret = watchdog_hardlockup_probe();
if (ret) {
- pr_info("Delayed init of the lockup detector failed: %d\n", ret);
+ if (ret == -ENODEV)
+ pr_info("NMI not fully supported\n");
+ else
+ pr_info("Delayed init of the lockup detector failed: %d\n", ret);
pr_info("Hard watchdog permanently disabled\n");
return;
}
_
Patches currently in -mm which might be from longman@xxxxxxxxxx are
watchdog-handle-the-enodev-failure-case-of-lockup_detector_delay_init-separately.patch
