um: remove PAGE_SIZE alignment in linker script causing kernel segfault.

commit 6915e04f8847bea16d0890f559694ad8eedd026c upstream.

The linker script cleanup that I did in commit 5d150a97f93 ("um: Clean up
linker script using standard macros.") (2.6.32) accidentally introduced an
ALIGN(PAGE_SIZE) when converting to use INIT_TEXT_SECTION; Richard
Weinberger reported that this causes the kernel to segfault with
CONFIG_STATIC_LINK=y.

I'm not certain why this extra alignment is a problem, but it seems likely
it is because previously

__init_begin = _stext = _text = _sinittext

and with the extra ALIGN(PAGE_SIZE), _sinittext becomes different from the
rest.  So there is likely a bug here where something is assuming that
_sinittext is the same as one of those other symbols.  But reverting the
accidental change fixes the regression, so it seems worth committing that
now.

Signed-off-by: Tim Abbott <tabbott@ksplice.com>
Reported-by: Richard Weinberger <richard@nod.at>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested by: Antoine Martin <antoine@nagafix.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/um/kernel/uml.lds.S b/arch/um/kernel/uml.lds.S
index ec63785506714f8059c9c7a31cf44d4875466698..9a873d765615af29fbb25779c6abb88d7af96bf2 100644 (file)
--- a/arch/um/kernel/uml.lds.S
+++ b/arch/um/kernel/uml.lds.S
@@ -22,7 +22,7 @@ SECTIONS
   _text = .;
   _stext = .;
   __init_begin = .;
-  INIT_TEXT_SECTION(PAGE_SIZE)
+  INIT_TEXT_SECTION(0)
   . = ALIGN(PAGE_SIZE);
 
   .text      :