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From: Al Viro <viro@zeniv.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCHSET v3 0/4] fs: Support for LOOKUP_NONBLOCK / RESOLVE_NONBLOCK (Insufficiently faking current?)
Date: Sun, 14 Feb 2021 21:24:33 +0000	[thread overview]
Message-ID: <YCmVETSedjnaxz7g@zeniv-ca.linux.org.uk> (raw)
In-Reply-To: <CAHk-=wiZuX-tyhR6rRxDfQOvyRkCVZjv0DCg1pHBUmzRZ_f1bQ@mail.gmail.com>

On Sun, Feb 14, 2021 at 12:30:07PM -0800, Linus Torvalds wrote:
> On Sun, Feb 14, 2021 at 8:38 AM Jens Axboe <axboe@kernel.dk> wrote:
> >
> > > Similarly it looks like opening of "/dev/tty" fails to
> > > return the tty of the caller but instead fails because
> > > io-wq threads don't have a tty.
> >
> > I've got a patch queued up for 5.12 that clears ->fs and ->files for the
> > thread if not explicitly inherited, and I'm working on similarly
> > proactively catching these cases that could potentially be problematic.
> 
> Well, the /dev/tty case still needs fixing somehow.
> 
> Opening /dev/tty actually depends on current->signal, and if it is
> NULL it will fall back on the first VT console instead (I think).
> 
> I wonder if it should do the same thing /proc/self does..

	I still think that entire "offload pathname resolution to helper
threads" thing is bollocks.  ->fs, ->files and ->signal is still nowhere
near enough - look at /proc/net, for example.  Or netns-sensitive parts
of sysfs, for that matter...  And that's not going into really weird crap
where opener is very special and assumed to be doing all IO.

  reply	other threads:[~2021-02-14 21:25 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-14 19:13 [PATCHSET v3 0/4] fs: Support for LOOKUP_NONBLOCK / RESOLVE_NONBLOCK Jens Axboe
2020-12-14 19:13 ` [PATCH 1/4] fs: make unlazy_walk() error handling consistent Jens Axboe
2020-12-14 19:13 ` [PATCH 2/4] fs: add support for LOOKUP_NONBLOCK Jens Axboe
2020-12-15 12:24   ` Matthew Wilcox
2020-12-15 15:29     ` Jens Axboe
2020-12-15 15:33       ` Matthew Wilcox
2020-12-15 15:37         ` Jens Axboe
2020-12-15 16:08           ` Jens Axboe
2020-12-15 16:14             ` Jens Axboe
2020-12-15 18:29             ` Linus Torvalds
2020-12-15 18:44               ` Jens Axboe
2020-12-15 18:47                 ` Linus Torvalds
2020-12-15 19:03                   ` Jens Axboe
2020-12-15 19:32                     ` Linus Torvalds
2020-12-15 19:38                       ` Jens Axboe
2020-12-16  2:36   ` Al Viro
2020-12-16  3:30     ` Jens Axboe
2020-12-16  2:43   ` Al Viro
2020-12-16  3:32     ` Jens Axboe
2020-12-14 19:13 ` [PATCH 3/4] fs: expose LOOKUP_NONBLOCK through openat2() RESOLVE_NONBLOCK Jens Axboe
2020-12-15 22:25   ` Dave Chinner
2020-12-15 22:31     ` Linus Torvalds
2020-12-15 23:25       ` Jens Axboe
2020-12-16  2:37   ` Al Viro
2020-12-16  3:39     ` Linus Torvalds
2020-12-14 19:13 ` [PATCH 4/4] io_uring: enable LOOKUP_NONBLOCK path resolution for filename lookups Jens Axboe
2020-12-15  3:06 ` [PATCHSET v3 0/4] fs: Support for LOOKUP_NONBLOCK / RESOLVE_NONBLOCK Linus Torvalds
2020-12-15  3:18   ` Jens Axboe
2020-12-15  6:11 ` Al Viro
2020-12-15 15:29   ` Jens Axboe
2021-01-04  5:31 ` Al Viro
2021-01-04 14:43   ` Jens Axboe
2021-01-04 16:54     ` Al Viro
2021-01-04 17:03       ` Jens Axboe
     [not found] ` <m1lfbrwrgq.fsf@fess.ebiederm.org>
2021-02-14 16:38   ` [PATCHSET v3 0/4] fs: Support for LOOKUP_NONBLOCK / RESOLVE_NONBLOCK (Insufficiently faking current?) Jens Axboe
2021-02-14 20:30     ` Linus Torvalds
2021-02-14 21:24       ` Al Viro [this message]
2021-02-15 18:07       ` Eric W. Biederman
2021-02-15 18:24         ` Jens Axboe
2021-02-15 21:09           ` Jens Axboe
2021-02-15 22:41             ` Eric W. Biederman
2021-02-16  2:41               ` Jens Axboe
2021-02-17  1:18                 ` Jens Axboe
2021-02-17  1:26                   ` Jens Axboe
2021-02-17  3:11                     ` Jens Axboe
2021-02-15 17:56     ` Eric W. Biederman

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