From: Matthew Wilcox <willy@infradead.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>,
Pavel Begunkov <asml.silence@gmail.com>,
io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 3/3] io_uring: refactor io_sq_offload_create()
Date: Sat, 24 Jul 2021 00:45:12 +0100 [thread overview]
Message-ID: <YPtUiLg7n8I+dpCT@casper.infradead.org> (raw)
In-Reply-To: <YPskZS1uLctRWz/f@zeniv-ca.linux.org.uk>
On Fri, Jul 23, 2021 at 08:19:49PM +0000, Al Viro wrote:
> To elaborate: ->release() instance may not assume anything about current->mm,
> or assume anything about current, for that matter. It is entirely possible
> to arrange its execution in context of a process that is not yours and had not
> consent to doing that. In particular, it's a hard bug to have _any_ visible
> effects depending upon the memory mappings, memory contents or the contents of
> descriptor table of the process in question.
Hmm. Could we add a poison_current() function? Something like ...
static inline void call_release(struct file *file, struct inode *inode)
{
void *tmp = poison_current();
if (file->f_op->release)
file->f_op->release(inode, file);
restore_current(tmp);
}
Should be straightforward for asm-generic/current.h and for x86 too.
Probably have to disable preemption? Maybe interrupts too? Not sure
what's kept in current these days that an interrupt handler might
rely on being able to access temporarily.
next prev parent reply other threads:[~2021-07-23 23:45 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-20 11:03 [PATCH 0/3] small 5.13 cleanups Pavel Begunkov
2021-04-20 11:03 ` [PATCH 1/3] io_uring: move inflight un-tracking into cleanup Pavel Begunkov
2021-04-20 11:03 ` [PATCH 2/3] io_uring: safer sq_creds putting Pavel Begunkov
2021-04-20 11:03 ` [PATCH 3/3] io_uring: refactor io_sq_offload_create() Pavel Begunkov
2021-07-22 21:59 ` Al Viro
2021-07-22 23:06 ` Jens Axboe
2021-07-22 23:30 ` Al Viro
2021-07-22 23:42 ` Jens Axboe
2021-07-23 0:10 ` Al Viro
2021-07-23 0:12 ` Al Viro
2021-07-23 16:17 ` Jens Axboe
2021-07-23 17:11 ` Al Viro
2021-07-23 17:32 ` Jens Axboe
2021-07-23 17:36 ` Jens Axboe
2021-07-23 17:56 ` Jens Axboe
2021-07-23 19:00 ` Al Viro
2021-07-23 20:10 ` Jens Axboe
2021-07-23 20:24 ` Al Viro
2021-07-23 22:32 ` Jens Axboe
2021-07-23 20:19 ` Al Viro
2021-07-23 23:45 ` Matthew Wilcox [this message]
2021-07-23 23:57 ` Jens Axboe
2021-07-24 1:31 ` Al Viro
2021-07-23 0:03 ` Al Viro
2021-07-23 9:59 ` Pavel Begunkov
2021-04-20 18:55 ` [PATCH 0/3] small 5.13 cleanups Jens Axboe
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