[IA64] Change SET_PERSONALITY to comply with comment in binfmt_elf.c.

We have a customer application which trips a bug.  The problem arises
when a driver attempts to call do_munmap on an area which is mapped, but
because current->thread.task_size has been set to 0xC0000000, the call
to do_munmap fails thinking it is an unmap beyond the user's address
space.

The comment in fs/binfmt_elf.c in load_elf_library() before the call
to SET_PERSONALITY() indicates that task_size must not be changed for
the running application until flush_thread, but is for ia64 executing
ia32 binaries.

This patch moves the setting of task_size from SET_PERSONALITY() to
flush_thread() as indicated.  The customer application no longer is able
to trip the bug.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 2e33665d9c1..a4da715a360 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -721,8 +721,11 @@ flush_thread (void)
         /* drop floating-point and debug-register state if it exists: */
         current->thread.flags &= ~(IA64_THREAD_FPH_VALID | IA64_THREAD_DBG_VALID);
         ia64_drop_fpu(current);
-        if (IS_IA32_PROCESS(ia64_task_regs(current)))
+        if (IS_IA32_PROCESS(ia64_task_regs(current))) {
                 ia32_drop_partial_page_list(current);
+                current->thread.task_size = IA32_PAGE_OFFSET;
+                set_fs(USER_DS);
+        }
 }
 
 /*