[PATCH] uml: fix oops related to exception table

      Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>

Prevent the kernel from oopsing during the extable sorting, as it can do
now, because the extable is in the readonly section of the binary.

Jeff says: The exception table turned RO in 2.6.11-rc3-mm1 for some reason.
Moving it causes it to land in the writable data section of the binary.

Paolo says: This patch fixes a oops on startup, which can be easily
triggered by compiling with CONFIG_MODE_TT disabled, and STATIC_LINK either
disabled or enabled.  The resulting kernel will always Oops on startup,
after printing this simple output:

I've verified, by binary search on the BitKeeper repository (synced up as
of 2.6.12-rc2), starting from the range 2.6.11-2.6.12-rc1, that this bug
shows up on BitKeeper revisions in the range [@1.1994.11.168,+inf), i.e.
starting from this:

[PATCH] lib/sort: Replace insertion sort in exception tables

Since UML does not use the exception table, it's likely that insertion sort
didn't happen to write anything on the table.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/asm-um/common.lds.S b/include/asm-um/common.lds.S
index a3d6aab..1010153 100644 (file)
--- a/include/asm-um/common.lds.S
+++ b/include/asm-um/common.lds.S
@@ -8,11 +8,6 @@
   _sdata = .;
   PROVIDE (sdata = .);
 
-  . = ALIGN(16);               /* Exception table */
-  __start___ex_table = .;
-  __ex_table : { *(__ex_table) }
-  __stop___ex_table = .;
-
   RODATA
 
   .unprotected : { *(.unprotected) }
@@ -20,6 +15,10 @@
   PROVIDE (_unprotected_end = .);
 
   . = ALIGN(4096);
+  __start___ex_table = .;
+  __ex_table : { *(__ex_table) }
+  __stop___ex_table = .;
+
   __uml_setup_start = .;
   .uml.setup.init : { *(.uml.setup.init) }
   __uml_setup_end = .;