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Subject[PATCH 1/5] vfork: don't freezer_count() for in-kernel users of CLONE_VFORK
Date
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.

Changes since v1:
* <20130215152840.GC30829@redhat.com> Oleg Nesterov
* Use (p->flags & PF_KTHREAD) checks instead of p->mm.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
CC: Oleg Nesterov <oleg@redhat.com>
CC: Tejun Heo <tj@kernel.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Rafael J. Wysocki <rjw@sisk.pl>
CC: Ingo Molnar <mingo@redhat.com>
---
kernel/fork.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index c535f33..c7ace33 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -722,9 +722,11 @@ static int wait_for_vfork_done(struct task_struct *child,
{
int killed;

- freezer_do_not_count();
+ if (!(current->flags & PF_KTHREAD))
+ freezer_do_not_count();
killed = wait_for_completion_killable(vfork);
- freezer_count();
+ if (!(current->flags & PF_KTHREAD))
+ freezer_count();

if (killed) {
task_lock(child);
--
1.7.12.4


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