linux/arch/um
Jeff Dike d79a580936 [PATCH] uml: console locking fixes
Clean up the console driver locking.  There are various problems here,
including sleeping under a spinlock and spinlock recursion, some of which are
fixed here.  This patch deals with the locking involved with opens and closes.
 The problem is that an mconsole request to change a console's configuration
can race with an open.  Changing a configuration should only be done when a
console isn't opened.  Also, an open must be looking at a stable
configuration.  In addition, a get configuration request must observe the same
locking since it must also see a stable configuration.  With the old locking,
it was possible for this to hang indefinitely in some cases because open would
block for a long time waiting for a connection from the host while holding the
lock needed by the mconsole request.

As explained in the long comment, this is fixed by adding a spinlock for the
use count and configuration and a mutex for the actual open and close.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11 10:51:21 -08:00
..
drivers [PATCH] uml: console locking fixes 2007-02-11 10:51:21 -08:00
include [PATCH] uml: console locking fixes 2007-02-11 10:51:21 -08:00
kernel [PATCH] tty: ->signal->tty locking 2006-12-08 08:28:38 -08:00
os-Linux [PATCH] uml: use get_random_bytes() after random pool is seeded 2006-12-07 08:39:29 -08:00
scripts kbuild: fix ia64 breakage after introducing make -rR 2006-07-01 09:58:02 +02:00
sys-i386 [PATCH] uml: fix signal frame alignment 2007-01-30 16:01:35 -08:00
sys-ia64 Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sys-ppc Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
sys-x86_64 [PATCH] uml: fix signal frame alignment 2007-01-30 16:01:35 -08:00
config.release Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
defconfig [PATCH] uml: remove syscall debugging 2006-07-10 13:24:24 -07:00
Kconfig [PATCH] UML: add generic BUG support 2006-12-08 08:28:39 -08:00
Kconfig.char [PATCH] uml: kconfig - silence warning 2006-10-20 10:26:36 -07:00
Kconfig.debug [PATCH] uml: remove syscall debugging 2006-07-10 13:24:24 -07:00
Kconfig.i386 [PATCH] fix indentation-related breakage in Kconfig.i386 2007-01-30 08:39:21 -08:00
Kconfig.net [PATCH] uml: Rename Kconfig files to be like the other arches 2005-09-05 00:06:19 -07:00
Kconfig.scsi [PATCH] uml: Rename Kconfig files to be like the other arches 2005-09-05 00:06:19 -07:00
Kconfig.x86_64 [PATCH] um: fix undefined reference to hweight32 2006-03-26 08:57:09 -08:00
Makefile [PATCH] uml: fix compilation options for USER_OBJS 2006-10-30 12:08:41 -08:00
Makefile-i386 [PATCH] uml: fix compilation options for USER_OBJS 2006-10-30 12:08:41 -08:00
Makefile-ia64 Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
Makefile-os-Linux Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
Makefile-ppc Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
Makefile-skas [PATCH] uml makefiles sanitized 2005-09-29 08:46:26 -07:00
Makefile-tt Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
Makefile-x86_64 [PATCH] uml: fix compilation options for USER_OBJS 2006-10-30 12:08:41 -08:00