diff options
Diffstat (limited to 'debian/patches-rt/0002-signal-Don-t-disable-preemption-in-ptrace_stop-on-PR.patch')
| -rw-r--r-- | debian/patches-rt/0002-signal-Don-t-disable-preemption-in-ptrace_stop-on-PR.patch | 48 |
1 files changed, 0 insertions, 48 deletions
diff --git a/debian/patches-rt/0002-signal-Don-t-disable-preemption-in-ptrace_stop-on-PR.patch b/debian/patches-rt/0002-signal-Don-t-disable-preemption-in-ptrace_stop-on-PR.patch deleted file mode 100644 index 01e89d97a..000000000 --- a/debian/patches-rt/0002-signal-Don-t-disable-preemption-in-ptrace_stop-on-PR.patch +++ /dev/null @@ -1,48 +0,0 @@ -From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> -Date: Thu, 3 Aug 2023 12:09:32 +0200 -Subject: [PATCH 2/2] signal: Don't disable preemption in ptrace_stop() on - PREEMPT_RT. -Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz - -On PREEMPT_RT keeping preemption disabled during the invocation of -cgroup_enter_frozen() is a problem because the function acquires css_set_lock -which is a sleeping lock on PREEMPT_RT and must not be acquired with disabled -preemption. -The preempt-disabled section is only for performance optimisation -reasons and can be avoided. - -Extend the comment and don't disable preemption before scheduling on -PREEMPT_RT. - -Acked-by: Oleg Nesterov <oleg@redhat.com> -Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> -Link: https://lore.kernel.org/r/20230803100932.325870-3-bigeasy@linutronix.de ---- - kernel/signal.c | 13 +++++++++++-- - 1 file changed, 11 insertions(+), 2 deletions(-) - ---- a/kernel/signal.c -+++ b/kernel/signal.c -@@ -2344,11 +2344,20 @@ static int ptrace_stop(int exit_code, in - * The preempt-disable section ensures that there will be no preemption - * between unlock and schedule() and so improving the performance since - * the ptracer has no reason to sleep. -+ * -+ * On PREEMPT_RT locking tasklist_lock does not disable preemption. -+ * Therefore the task can be preempted (after -+ * do_notify_parent_cldstop()) before unlocking tasklist_lock so there -+ * is no benefit in doing this. The optimisation is harmful on -+ * PEEMPT_RT because the spinlock_t (in cgroup_enter_frozen()) must not -+ * be acquired with disabled preemption. - */ -- preempt_disable(); -+ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) -+ preempt_disable(); - read_unlock(&tasklist_lock); - cgroup_enter_frozen(); -- preempt_enable_no_resched(); -+ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) -+ preempt_enable_no_resched(); - schedule(); - cgroup_leave_frozen(true); - |