Re: [PATCH] watchdog: Fix watchdog_nmi_enable_all()

From: Ulrich Obergfell
Date: Thu Apr 23 2015 - 04:30:40 EST


> ----- Original Message -----
> From: "Andrew Morton" <akpm@xxxxxxxxxxxxxxxxxxxx>
> To: "Don Zickus" <dzickus@xxxxxxxxxx>
> Cc: "LKML" <linux-kernel@xxxxxxxxxxxxxxx>, "Ulrich Obergfell" <uobergfe@xxxxxxxxxx>
> Sent: Wednesday, April 22, 2015 10:12:01 PM
> Subject: Re: [PATCH] watchdog: Fix watchdog_nmi_enable_all()
>
> On Wed, 22 Apr 2015 10:47:49 -0400 Don Zickus <dzickus@xxxxxxxxxx> wrote:
>
>> From: Ulrich Obergfell <uobergfe@xxxxxxxxxx>
>>
>> The 'watchdog_user_enabled' variable is only used as an 'interface'
>> to the /proc/sys/kernel/watchdog parameter. The actual state of the
>> watchdog is tracked by bits in the 'watchdog_enabled' variable. So,
>> watchdog_nmi_enable_all() should check the NMI_WATCHDOG_ENABLED bit
>> in 'watchdog_enabled'.
>
> What are the user-visible effects of the patch? Please always include
> this information when fixing a bug.

Andrew,

this patch has no user-visible effects. The issue that is addressed by this
patch came up during the recent merges. It is related to:

1) https://lkml.org/lkml/2015/2/5/624
2) http://lkml.kernel.org/r/1416251225-17721-12-git-send-email-eranian@xxxxxxxxxx

Patch series 1) changes the way how the code in kernel/watchdog.c uses certain
variables such as 'watchdog_user_enabled' and it also introduces a new variable
'watchdog_enabled' as described in:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/kernel/watchdog.c?id=84d56e66b9b4a646f04ec30696ca1aeea5e654d5

This patch adjusts patch 2) which introduces watchdog_nmi_enable_all() to the
new way how the code in kernel/watchdog.c should use 'watchdog_user_enabled'
and 'watchdog_enabled'. Patch 2) is here:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/kernel/watchdog.c?id=b3738d29323344da3017a91010530cf3a58590fc


Regards,

Uli
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