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  1. 14 May, 2011 1 commit
    • Linus Torvalds's avatar
      fbmem: fix remove_conflicting_framebuffers races · 712f3147
      Linus Torvalds authored 
      When a register_framebuffer() call results in us removing old
conflicting framebuffers, the new registration_lock doesn't protect that
situation.  And we can't just add the same locking to the function,
because these functions call each other: register_framebuffer() calls
remove_conflicting_framebuffers, which in turn calls
unregister_framebuffer for any conflicting entry.

In order to fix it, this just creates wrapper functions around all three
functions and makes the versions that actually do the work be called
"do_xxx()", leaving just the wrapper that gets the lock and calls the
worker function.

So the rule becomes simply that "do_xxxx()" has to be called with the
lock held, and now do_register_framebuffer() can just call
do_remove_conflicting_framebuffers(), and that in turn can call
_do_unregister_framebuffer(), and there is no deadlock, and we can hold
the registration lock over the whole sequence, fixing the races.

It also makes error cases simpler, and fixes one situation where we
would return from unregister_framebuffer() without releasing the lock,
pointed out by Bruno Prémont.
Tested-by: default avatarBruno Prémont <bonbons@linux-vserver.org>
Tested-by: default avatarAnca Emanuel <anca.emanuel@gmail.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      712f3147
  3. 12 May, 2011 2 commits
    • Linus Torvalds's avatar
      fbmem: make read/write/ioctl use the frame buffer at open time · c47747fd
      Linus Torvalds authored 
      read/write/ioctl on a fbcon file descriptor has traditionally used the
fbcon not when it was opened, but as it was at the time of the call.
That makes no sense, but the lack of sense is much more obvious now that
we properly ref-count the usage - it means that the ref-counting doesn't
actually protect operations we do on the frame buffer.

This changes it to look at the fb_info that we got at open time, but in
order to avoid using a frame buffer long after it has been unregistered,
we do verify that it is still current, and return -ENODEV if not.
Acked-by: default avatarTim Gardner <tim.gardner@canonical.com>
Tested-by: default avatarDaniel J Blueman <daniel.blueman@gmail.com>
Tested-by: default avatarAnca Emanuel <anca.emanuel@gmail.com>
Cc: Bruno Prémont <bonbons@linux-vserver.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Andy Whitcroft <andy.whitcroft@canonical.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c47747fd
    • Linus Torvalds's avatar
      fbcon: add lifetime refcount to opened frame buffers · 698b3682
      Linus Torvalds authored 
      This just adds the refcount and the new registration lock logic.  It
does not (for example) actually change the read/write/ioctl routines to
actually use the frame buffer that was opened: those function still end
up alway susing whatever the current frame buffer is at the time of the
call.

Without this, if something holds the frame buffer open over a
framebuffer switch, the close() operation after the switch will access a
fb_info that has been free'd by the unregistering of the old frame
buffer.

(The read/write/ioctl operations will normally not cause problems,
because they will - illogically - pick up the new fbcon instead.  But a
switch that happens just as one of those is going on might see problems
too, the window is just much smaller: one individual op rather than the
whole open-close sequence.)

This use-after-free is apparently fairly easily triggered by the Ubuntu
11.04 boot sequence.
Acked-by: default avatarTim Gardner <tim.gardner@canonical.com>
Tested-by: default avatarDaniel J Blueman <daniel.blueman@gmail.com>
Tested-by: default avatarAnca Emanuel <anca.emanuel@gmail.com>
Cc: Bruno Prémont <bonbons@linux-vserver.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Andy Whitcroft <andy.whitcroft@canonical.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      698b3682
  5. 11 May, 2011 2 commits
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 · 9f381a61
      Linus Torvalds authored 
      * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (27 commits)
  slcan: fix ldisc->open retval
  net/usb: mark LG VL600 LTE modem ethernet interface as WWAN
  xfrm: Don't allow esn with disabled anti replay detection
  xfrm: Assign the inner mode output function to the dst entry
  net: dev_close() should check IFF_UP
  vlan: fix GVRP at dismantle time
  netfilter: revert a2361c87
  netfilter: IPv6: fix DSCP mangle code
  netfilter: IPv6: initialize TOS field in REJECT target module
  IPVS: init and cleanup restructuring
  IPVS: Change of socket usage to enable name space exit.
  netfilter: ebtables: only call xt_compat_add_offset once per rule
  netfilter: fix ebtables compat support
  netfilter: ctnetlink: fix timestamp support for new conntracks
  pch_gbe: support ML7223 IOH
  PCH_GbE : Fixed the issue of checksum judgment
  PCH_GbE : Fixed the issue of collision detection
  NET: slip, fix ldisc->open retval
  be2net: Fixed bugs related to PVID.
  ehea: fix wrongly reported speed and port
  ...
      9f381a61
    • David Rientjes's avatar
      slub: Revert "[PARISC] slub: fix panic with DISCONTIGMEM" · 21a43e39
      David Rientjes authored 
      This reverts commit 4a5fa359, which did not allow SLUB to be used
on architectures that use DISCONTIGMEM without compiling NUMA support
without CONFIG_BROKEN also set.

The slub panic that it was intended to prevent is addressed by
d9b41e0b ("[PARISC] set memory ranges in N_NORMAL_MEMORY when
onlined") on parisc so there is no further slub issues with such a
configuration.

The reverts allows SLUB now to be used on such architectures since
there haven't been any reports of additional errors.

Cc: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      21a43e39
  7. 10 May, 2011 35 commits
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