Do not enable CONFIG_IO_STRICT_DEVMEM by default

Larry Finger reports:
 "My PowerBook G4 Aluminum with a 32-bit PPC processor fails to boot for
  the 4.4-git series".

This is likely due to X still needing /dev/mem access on this platform.

CONFIG_IO_STRICT_DEVMEM is not yet safe to turn on when
CONFIG_STRICT_DEVMEM=y.

Remove the default so that old configurations do not change behavior.

Fixes: 90a545e98126 ("restrict /dev/mem to idle io memory ranges")
Reported-by: Larry Finger <Larry.Finger@lwfinger.net>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Link: http://marc.info/?l=linux-kernel&m=145332012023825&w=2
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index f75a33f..7d0b49c 100644 (file)
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1919,7 +1919,6 @@ config STRICT_DEVMEM
 config IO_STRICT_DEVMEM
        bool "Filter I/O access to /dev/mem"
        depends on STRICT_DEVMEM
-       default STRICT_DEVMEM
        ---help---
          If this option is disabled, you allow userspace (root) access to all
          io-memory regardless of whether a driver is actively using that