Hello, Linus.
Sorry, I sat on this for too long.
There's an inadvertent preemption point in ptrace_stop() which was
reliably triggering for a test scenario significantly slowing it down.
This pull request contains Oleg's fix to remove the unwanted
preemption point.
Thanks.
The following changes since commit 9e208aa06c2109b45eec6be049a8e47034748c20:
Merge tag 'xfs-5.4-fixes-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux (2019-10-10 11:47:16 -0700)
are available in the Git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-5.4-fixes
for you to fetch changes up to 937c6b27c73e02cd4114f95f5c37ba2c29fadba1:
cgroup: freezer: call cgroup_enter_frozen() with preemption disabled in ptrace_stop() (2019-10-11 08:39:57 -0700)
----------------------------------------------------------------
Oleg Nesterov (1):
cgroup: freezer: call cgroup_enter_frozen() with preemption disabled in ptrace_stop()
kernel/signal.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/signal.c b/kernel/signal.c
index c4da1ef56fdf..bcd46f547db3 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2205,8 +2205,8 @@ static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t
*/
preempt_disable();
read_unlock(&tasklist_lock);
- preempt_enable_no_resched();
cgroup_enter_frozen();
+ preempt_enable_no_resched();
freezable_schedule();
cgroup_leave_frozen(true);
} else {
--
tejun
