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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Network Development <netdev@vger.kernel.org>
Subject: Re: [RFC][PATCHES] iov_iter.c rewrite
Date: Mon, 8 Dec 2014 18:14:04 +0000	[thread overview]
Message-ID: <20141208181401.GD22149@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CA+55aFz6izpVGxkziynRXg7zbHzteQyPJH1Kg91ZO3fzqn3LaQ@mail.gmail.com>

On Mon, Dec 08, 2014 at 10:07:55AM -0800, Linus Torvalds wrote:

> Which is in the vmalloc address space. So somebody used a vmalloc'ed
> address and tried to convert it to a physical address in order to look
> up the page.
> 
> Which is not a valid operation, and the BUG_ON() is definitely proper.
> 
> Now *why* something tried to do a virt_to_page() on a vmalloc'ed
> address, that I leave to others.

iov_iter_get_pages() in ITER_KVEC case, trying to avoid get_user_pages_fast()
and getting it wrong.  FWIW, the reproducer is finit_module(fd, ....)
where fd has been opened with O_DIRECT.  In that case we get kernel_read()
on O_DIRECT and the buffer has just been vmalloc'ed.

What's the sane way to grab struct page * for a vmalloc'ed address?

  reply	other threads:[~2014-12-08 18:14 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-04 20:20 [RFC][PATCHES] iov_iter.c rewrite Al Viro
2014-12-04 20:23 ` [RFC][PATCH 01/13] iov_iter.c: macros for iterating over iov_iter Al Viro
2014-12-04 20:23 ` [RFC][PATCH 02/13] iov_iter.c: iterate_and_advance Al Viro
2014-12-04 20:23 ` [RFC][PATCH 03/13] iov_iter.c: convert iov_iter_npages() to iterate_all_kinds Al Viro
2014-12-04 20:23 ` [RFC][PATCH 04/13] iov_iter.c: convert iov_iter_get_pages() " Al Viro
2014-12-04 20:23 ` [RFC][PATCH 05/13] iov_iter.c: convert iov_iter_get_pages_alloc() " Al Viro
2014-12-04 20:23 ` [RFC][PATCH 06/13] iov_iter.c: convert iov_iter_zero() to iterate_and_advance Al Viro
2014-12-04 20:23 ` [RFC][PATCH 07/13] iov_iter.c: get rid of bvec_copy_page_{to,from}_iter() Al Viro
2014-12-05 12:28   ` Sergei Shtylyov
2014-12-04 20:23 ` [RFC][PATCH 08/13] iov_iter.c: convert copy_from_iter() to iterate_and_advance Al Viro
2014-12-04 20:23 ` [RFC][PATCH 09/13] iov_iter.c: convert copy_to_iter() " Al Viro
2014-12-04 20:23 ` [RFC][PATCH 10/13] iov_iter.c: handle ITER_KVEC directly Al Viro
2014-12-04 20:23 ` [RFC][PATCH 11/13] csum_and_copy_..._iter() Al Viro
2014-12-04 20:23 ` [RFC][PATCH 12/13] new helper: iov_iter_kvec() Al Viro
2014-12-04 20:23 ` [RFC][PATCH 13/13] copy_from_iter_nocache() Al Viro
2014-12-08 16:46 ` [RFC][PATCHES] iov_iter.c rewrite Kirill A. Shutemov
2014-12-08 17:58   ` Al Viro
2014-12-08 18:08     ` Al Viro
2014-12-08 18:14       ` Linus Torvalds
2014-12-08 18:20         ` Al Viro
2014-12-08 18:37           ` Linus Torvalds
2014-12-08 18:46             ` Al Viro
2014-12-08 18:57               ` Linus Torvalds
2014-12-08 19:28                 ` Al Viro
2014-12-08 19:48                   ` Linus Torvalds
2014-12-09  1:56                   ` Al Viro
2014-12-09  2:21                     ` Kirill A. Shutemov
2015-04-01  2:33                 ` [RFC] iov_iter_get_pages() semantics Al Viro
2015-04-01 16:45                   ` Linus Torvalds
2015-04-01 18:08                     ` Al Viro
2015-04-01 18:15                       ` Linus Torvalds
2015-04-01 19:23                         ` Al Viro
2015-04-01 18:26                       ` Linus Torvalds
2015-04-01 18:34                         ` Linus Torvalds
2015-04-01 20:15                           ` Al Viro
2015-04-01 21:57                             ` Linus Torvalds
2015-04-01 19:50                         ` Al Viro
2014-12-08 18:56     ` [RFC][PATCHES] iov_iter.c rewrite Kirill A. Shutemov
2014-12-08 19:01       ` Linus Torvalds
2014-12-08 19:15         ` Dave Jones
2014-12-08 19:23         ` Kirill A. Shutemov
2014-12-08 22:14           ` Theodore Ts'o
2014-12-08 22:23             ` Linus Torvalds
2014-12-08 22:31               ` Dave Jones
2014-12-08 18:07   ` Linus Torvalds
2014-12-08 18:14     ` Al Viro [this message]
2014-12-08 18:23       ` Linus Torvalds
2014-12-08 18:35         ` Al Viro

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