From: Al Viro <viro@zeniv.linux.org.uk>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v2] fput: Allow calling __fput_sync() from !PF_KTHREAD thread.
Date: Thu, 10 Sep 2020 12:25:24 +0100 [thread overview]
Message-ID: <20200910112524.GY1236603@ZenIV.linux.org.uk> (raw)
In-Reply-To: <dae15011-24b0-b382-218a-c988b435fb5c@i-love.sakura.ne.jp>
On Thu, Sep 10, 2020 at 02:26:46PM +0900, Tetsuo Handa wrote:
> Thank you for responding. I'm also waiting for your response on
> "[RFC PATCH] pipe: make pipe_release() deferrable." at
> https://lore.kernel.org/linux-fsdevel/7ba35ca4-13c1-caa3-0655-50d328304462@i-love.sakura.ne.jp/
> and "[PATCH] splice: fix premature end of input detection" at
> https://lore.kernel.org/linux-block/cf26a57e-01f4-32a9-0b2c-9102bffe76b2@i-love.sakura.ne.jp/ .
>
> >
> > NAK. The reason to defer is *NOT* to bypass that BUG_ON() - we really do not
> > want that thing done on anything other than extremely shallow stack.
> > Incidentally, why is that thing ever done _not_ in a kernel thread context?
>
> What does "that thing" refer to? acct_pin_kill() ? blob_to_mnt() ?
> I don't know the reason because I'm not the author of these functions.
The latter. What I mean, why not simply do that from inside of
fork_usermode_driver()? umd_setup is stored in sub_info->init and
eventually called from call_usermodehelper_exec_async(), right before
the created kernel thread is about to call kernel_execve() and stop
being a kernel thread...
next prev parent reply other threads:[~2020-09-10 21:58 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-08 14:24 [PATCH] fput: Allow calling __fput_sync() from !PF_KTHREAD thread Tetsuo Handa
2020-07-29 13:04 ` [PATCH v2] " Tetsuo Handa
2020-08-19 12:42 ` [PATCH v2 (resend)] " Tetsuo Handa
2020-09-09 21:59 ` Tetsuo Handa
2020-09-10 3:57 ` [PATCH v2] " Al Viro
2020-09-10 5:26 ` Tetsuo Handa
2020-09-10 11:25 ` Al Viro [this message]
2020-09-10 20:06 ` Eric W. Biederman
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