linux-kernel - Re: /proc/kmsg giving eof on blocking read

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Date:	Thu, 22 Nov 2012 13:29:00 +0100
From:	Kay Sievers <kay@...y.org>
To:	Jan Schmidt <list.lkml@...-o-sch.net>
Cc:	LKML <linux-kernel@...r.kernel.org>
Subject: Re: /proc/kmsg giving eof on blocking read

On Thu, Nov 22, 2012 at 11:44 AM, Jan Schmidt <list.lkml@...-o-sch.net> wrote:
> I'm currently debugging something in btrfs in good old printk style, generating
> around 10MB/min. I'm seeing /proc/kmsg returning eof on a blocking read (and,
> side note, syslog-ng won't reopen it, effectively stopping logging kernel
> messages silently).

Are you sure there is not something else that opens the same file?
Even once might be enough to return 0. The too simple locking logic in
/proc/kmsg cannot support multiple readers properly, it never did.

Kay
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