+ vfork-dont-freezer_count-for-in-kernel-users-of-clone_vfork.patch added to -mm tree

+ vfork-dont-freezer_count-for-in-kernel-users-of-clone_vfork.patch added to -mm tree

[akpm]

The patch titled
     Subject: vfork: don't freezer_count() for in-kernel users of CLONE_VFORK
has been added to the -mm tree.  Its filename is
     vfork-dont-freezer_count-for-in-kernel-users-of-clone_vfork.patch

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------------------------------------------------------
From: Mandeep Singh Baines <msb@chromium.org>
Subject: vfork: don't freezer_count() for in-kernel users of CLONE_VFORK

We don't need to call freezer_do_not_count() for in-kernel users of
CLONE_VFORK since exec will get called in bounded time.

We don't want to call freezer_count() for in-kernel users because they may
be holding locks.  freezer_count() calls try_to_freeze().  We don't want
to freeze an in-kernel user because it may be holding locks.

In a follow-up patch, I call debug_check_no_locks_held() from
try_to_freeze().  After applying this patch, I get no lockdep warnings
with that patch.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Ben Chan <benchan@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/fork.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff -puN kernel/fork.c~vfork-dont-freezer_count-for-in-kernel-users-of-clone_vfork kernel/fork.c
--- a/kernel/fork.c~vfork-dont-freezer_count-for-in-kernel-users-of-clone_vfork
+++ a/kernel/fork.c
@@ -718,9 +718,11 @@ static int wait_for_vfork_done(struct ta
 {
 	int killed;
 
-	freezer_do_not_count();
+	if (current->mm)
+		freezer_do_not_count();
 	killed = wait_for_completion_killable(vfork);
-	freezer_count();
+	if (current->mm)
+		freezer_count();
 
 	if (killed) {
 		task_lock(child);
_

Patches currently in -mm which might be from msb@chromium.org are

vfork-dont-freezer_count-for-in-kernel-users-of-clone_vfork.patch
lockdep-check-that-no-locks-held-at-freeze-time.patch
coredump-cleanup-the-waiting-for-coredump_finish-code.patch
coredump-use-a-freezable_schedule-for-the-coredump_finish-wait.patch
coredump-abort-core-dump-piping-only-due-to-a-fatal-signal.patch