[GIT PULL] cgroup fix for v5.2-rc1

[Tejun Heo]

Hello, Linus.

The cgroup2 freezer pulled in this cycle broke strace.  This pull
request includes a workaround for the problem.  It's not a complete
fix in that it may cause spurious frozen state flip-flops which is
fairly minor.  Will push a full fix once it's ready.

Thanks.

The following changes since commit 8c05f3b965da14e7790711026b32cc10a4c06213:

  Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm (2019-05-16 09:41:54 -0700)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-5.2-fixes

for you to fetch changes up to 05b289263772b0698589abc47771264a685cd365:

  signal: unconditionally leave the frozen state in ptrace_stop() (2019-05-16 10:43:58 -0700)

----------------------------------------------------------------
Roman Gushchin (1):
      signal: unconditionally leave the frozen state in ptrace_stop()

 kernel/signal.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/signal.c b/kernel/signal.c
index c4dd66436fc5..a1eb44dc9ff5 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2113,6 +2113,7 @@ static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t
 		preempt_enable_no_resched();
 		cgroup_enter_frozen();
 		freezable_schedule();
+		cgroup_leave_frozen(true);
 	} else {
 		/*
 		 * By the time we got the lock, our tracer went away.

-- 
tejun