c/r: prctl: update prctl_set_mm_exe_file() after mm->num_exe_file_vmas removal
authorKonstantin Khlebnikov <khlebnikov@openvz.org>
Thu, 7 Jun 2012 21:21:11 +0000 (14:21 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 7 Jun 2012 21:43:55 +0000 (14:43 -0700)
commitbafb282df29c1524b1617019adebd6d0c3eb7a47
treef0b9efa850b4b298ce484eead5c8d9de87dde3e9
parent6305902c2f871fd6db60af367bd7120fa977fa74
c/r: prctl: update prctl_set_mm_exe_file() after mm->num_exe_file_vmas removal

A fix for commit b32dfe377102 ("c/r: prctl: add ability to set new
mm_struct::exe_file").

After removing mm->num_exe_file_vmas kernel keeps mm->exe_file until
final mmput(), it never becomes NULL while task is alive.

We can check for other mapped files in mm instead of checking
mm->num_exe_file_vmas, and mark mm with flag MMF_EXE_FILE_CHANGED in
order to forbid second changing of mm->exe_file.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/sched.h
kernel/sys.c