All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jan Kiszka <jan.kiszka@siemens.com>
To: Jean Delvare <jdelvare@suse.de>,
	linux-watchdog@vger.kernel.org,
	LKML <linux-kernel@vger.kernel.org>,
	stable@vger.kernel.org
Cc: Guenter Roeck <linux@roeck-us.net>,
	Wim Van Sebroeck <wim@linux-watchdog.org>,
	Michael Marley <michael@michaelmarley.com>
Subject: Re: Faulty commit "watchdog: iTCO_wdt: Account for rebooting on second timeout"
Date: Tue, 3 Aug 2021 16:59:02 +0200	[thread overview]
Message-ID: <e13f45c4-70e2-e2c2-9513-ce38c8235b4f@siemens.com> (raw)
In-Reply-To: <20210803165108.4154cd52@endymion>

On 03.08.21 16:51, Jean Delvare wrote:
> Hi all,
> 
> Commit cb011044e34c ("watchdog: iTCO_wdt: Account for rebooting on
> second timeout") causes a regression on several systems. Symptoms are:
> system reboots automatically after a short period of time if watchdog
> is enabled (by systemd for example). This has been reported in bugzilla:
> 
> https://bugzilla.kernel.org/show_bug.cgi?id=213809
> 
> Unfortunately this commit was backported to all stable kernel branches
> (4.14, 4.19, 5.4, 5.10, 5.12 and 5.13). I'm not sure why that is the
> case, BTW, as there is no Fixes tag and no Cc to stable@vger either.
> And the fix is not trivial, has apparently not seen enough testing,
> and addresses a problem that has a known and simple workaround. IMHO it
> should never have been accepted as a stable patch in the first place.
> Especially when the previous attempt to fix this issue already ended
> with a regression and a revert.
> 
> Anyway... After a glance at the patch, I see what looks like a nice
> thinko:
> 
> +	if (p->smi_res &&
> +	    (SMI_EN(p) & (TCO_EN | GBL_SMI_EN)) != (TCO_EN | GBL_SMI_EN))
> 
> The author most certainly meant inl(SMI_EN(p)) (the register's value)
> and not SMI_EN(p) (the register's address).
> 

https://lkml.org/lkml/2021/7/26/349

Jan

-- 
Siemens AG, T RDA IOT
Corporate Competence Center Embedded Linux

  reply	other threads:[~2021-08-03 14:59 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-03 14:51 Faulty commit "watchdog: iTCO_wdt: Account for rebooting on second timeout" Jean Delvare
2021-08-03 14:59 ` Jan Kiszka [this message]
2021-08-03 15:01   ` Jan Kiszka
2021-08-03 15:27     ` Guenter Roeck
2021-08-03 15:32   ` Jean Delvare
2021-08-04  0:04   ` Michael Marley
2021-08-04  6:58     ` Jan Kiszka
2021-08-06  6:28 ` Greg KH

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=e13f45c4-70e2-e2c2-9513-ce38c8235b4f@siemens.com \
    --to=jan.kiszka@siemens.com \
    --cc=jdelvare@suse.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-watchdog@vger.kernel.org \
    --cc=linux@roeck-us.net \
    --cc=michael@michaelmarley.com \
    --cc=stable@vger.kernel.org \
    --cc=wim@linux-watchdog.org \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.