This set of patches fixes an proc ->open'less usage due to ->proc_fops flip in
the most part of the kernel code. The original OOPS is described in the
commit 2d3a4e3666325a9709cc8ea2e88151394e8f20fc:
Typical PDE creation code looks like:
pde = create_proc_entry("foo", 0, NULL);
if (pde)
pde->proc_fops = &foo_proc_fops;
Notice that PDE is first created, only then ->proc_fops is set up to
final value. This is a problem because right after creation
a) PDE is fully visible in /proc , and
b) ->proc_fops are proc_file_operations which do not have ->open callback. So, it's
possible to ->read without ->open (see one class of oopses below).
The fix is new API called proc_create() which makes sure ->proc_fops are
set up before gluing PDE to main tree. Typical new code looks like:
pde = proc_create("foo", 0, NULL, &foo_proc_fops);
if (!pde)
return -ENOMEM;
Fix most networking users for a start.
In the long run, create_proc_entry() for regular files will go.
In addition to this, proc_create_data is introduced to fix reading from
proc without PDE->data. The race is basically the same as above.
create_proc_entries is replaced in the entire kernel code as new method
is also simply better.
This patch:
The problem is the same as for de->proc_fops. Right now PDE becomes visible
without data set. So, the entry could be looked up without data. This, in
most cases, will simply OOPS.
proc_create_data call is created to address this issue. proc_create now
becomes a wrapper around it.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Chris Mason <chris.mason@oracle.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jaroslav Kysela <perex@suse.cz>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Kyle McMartin <kyle@parisc-linux.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Neil Brown <neilb@suse.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Osterlund <petero2@telia.com>
Cc: Pierre Peiffer <peifferp@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
59b7435149