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@xxxxxxxxxxxx>
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@xxxxxxxxxxxx>
Cc: Ben Chan <benchan@xxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Rafael J. Wysocki <rjw@xxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxxxx 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
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