Re: "blocked for more than 120 secs" --> a valid situation, how toprevent?

From: Kyle McMartin
Date: Thu Sep 23 2010 - 22:08:53 EST


On Thu, Sep 23, 2010 at 07:41:28PM -0400, Mark Lord wrote:
> What's the purpose of this stack dump,
> and how can it be prevented in this NORMAL situation??
>
> The command was "hdparm --security-erase NULL /dev/sdb",
> which takes about 66 minutes to complete on this particular drive.
>
> I don't see any obvious way for the task to mark itself
> as needing longer than 120 secs to complete the operation.
>

It's an excellent question, a large number of bug reports I see against
Fedora are the result of this firing on some long-running task (like a
huge 'sync') and the user getting scared by the message assuming the
universe was imploding and reporting a bug.

I'd suggest we add a new task_struct flag for it, but we appear to be
out of bits! Perhaps we can abuse one of the other ones (PF_FROZEN seems
the likely choice since the watchdog bails out if it sees it, but that
likely has other ramifications.)

--Kyle
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