From: Alan Cox <alan@linux.intel.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: lkml <linux-kernel@vger.kernel.org>,
"Greg Kroah-Hartman" <gregkh@suse.de>
Subject: Re: possible locking bug in tty_open
Date: Tue, 4 May 2010 10:43:05 +0100 [thread overview]
Message-ID: <20100504104305.29e7ada7@linux.intel.com> (raw)
In-Reply-To: <201005022247.33857.arnd@arndb.de>
On Sun, 2 May 2010 22:47:33 +0200
Arnd Bergmann <arnd@arndb.de> wrote:
> While playing some more with my TTY BKL patches, I stumbled over
> what looks like a bug in tty_open, introduced in e8c6210
> "tty: push the BKL down into the handlers a bit":
>
> After the "retry_open:" label, we first get the tty_mutex
> and then the BKL. However a the end of tty_open, we jump
> back to retry_open with the BKL still held. If we run into
> this case, the tty_open function will be left with the BKL
> still held.
>
> It may be impossible to actually trigger this bug, because
> the path is only taken if a tty driver open function returns
> -ERESTARTSYS without setting signal_pending().
It looks pretty much impossible to trigger but it's definitely a bug.
I'll send Greg a patch
next prev parent reply other threads:[~2010-05-04 10:21 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-02 20:47 possible locking bug in tty_open Arnd Bergmann
2010-05-04 9:43 ` Alan Cox [this message]
2010-05-04 19:42 ` Alan Cox
2010-05-04 20:26 ` Arnd Bergmann
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