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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAPXgP13OyV-hT=D_-rOyuk2_4n1deQ57ZdRvooBS5Z=sHM_HuQ@mail.gmail.com>
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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/