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From: Al Viro <viro@zeniv.linux.org.uk>
To: Jens Axboe <axboe@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Christoph Hellwig <hch@lst.de>, Kyle Huey <me@kylehuey.com>
Subject: Re: [PATCH] Fix compat regression in process_vm_rw()
Date: Tue, 27 Oct 2020 00:09:20 +0000	[thread overview]
Message-ID: <20201027000920.GE3576660@ZenIV.linux.org.uk> (raw)
In-Reply-To: <f69575e0-5170-2d51-8d74-8b3453723aa3@kernel.dk>

On Mon, Oct 26, 2020 at 06:03:18PM -0600, Jens Axboe wrote:
> The removal of compat_process_vm_{readv,writev} didn't change
> process_vm_rw(), which always assumes it's not doing a compat syscall.
> Instead of passing in 'false' unconditionally for 'compat', make it
> conditional on in_compat_syscall().
> 
> Fixes: c3973b401ef2 ("mm: remove compat_process_vm_{readv,writev}")
> Reported-by: Kyle Huey <me@kylehuey.com>
> Signed-off-by: Jens Axboe <axboe@kernel.dk>

ACK with some reservations - I suspect that we want an explicit flag
for process_vm_{read,write}v() that would force the 64bit layout for
the vector refering to the foreign process.  It's not relevant for
regression fix; however, as it is these syscalls are not usable for
32bit process trying to access memory of 64bit one - there's no way
to specify the addresses past 4G.

  reply	other threads:[~2020-10-27  0:41 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-27  0:03 [PATCH] Fix compat regression in process_vm_rw() Jens Axboe
2020-10-27  0:09 ` Al Viro [this message]
2020-10-27  8:01   ` Christoph Hellwig
2020-10-27 17:00     ` Linus Torvalds
2020-10-27  0:47 ` Kyle Huey
2020-10-27  8:00 ` Christoph Hellwig
2020-10-27 19:19 ` damian
2020-10-27 19:27   ` Naresh Kamboju
2020-10-27 19:32   ` Jens Axboe

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