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-rw-r--r--debian/patches-rt/0274-Revert-futex-workaround-migrate_disable-enable-in-di.patch66
1 files changed, 66 insertions, 0 deletions
diff --git a/debian/patches-rt/0274-Revert-futex-workaround-migrate_disable-enable-in-di.patch b/debian/patches-rt/0274-Revert-futex-workaround-migrate_disable-enable-in-di.patch
new file mode 100644
index 000000000..b2f940fe5
--- /dev/null
+++ b/debian/patches-rt/0274-Revert-futex-workaround-migrate_disable-enable-in-di.patch
@@ -0,0 +1,66 @@
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 26 Jun 2019 17:44:27 +0200
+Subject: [PATCH 274/342] Revert "futex: workaround migrate_disable/enable in
+ different context"
+Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=188a1d1aaac5e0288814560fad22b3c638bad3bd
+
+[ Upstream commit a71221d81cc4873891ae44f3aa02df596079b786 ]
+
+Drop the RT fixup, the futex code will be changed to avoid the need for
+the workaround.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
+---
+ kernel/futex.c | 19 -------------------
+ 1 file changed, 19 deletions(-)
+
+diff --git a/kernel/futex.c b/kernel/futex.c
+index bcd01b5a47df..9bcfdcffb2dd 100644
+--- a/kernel/futex.c
++++ b/kernel/futex.c
+@@ -2998,14 +2998,6 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
+ * before __rt_mutex_start_proxy_lock() is done.
+ */
+ raw_spin_lock_irq(&q.pi_state->pi_mutex.wait_lock);
+- /*
+- * the migrate_disable() here disables migration in the in_atomic() fast
+- * path which is enabled again in the following spin_unlock(). We have
+- * one migrate_disable() pending in the slow-path which is reversed
+- * after the raw_spin_unlock_irq() where we leave the atomic context.
+- */
+- migrate_disable();
+-
+ spin_unlock(q.lock_ptr);
+ /*
+ * __rt_mutex_start_proxy_lock() unconditionally enqueues the @rt_waiter
+@@ -3014,7 +3006,6 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
+ */
+ ret = __rt_mutex_start_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter, current);
+ raw_spin_unlock_irq(&q.pi_state->pi_mutex.wait_lock);
+- migrate_enable();
+
+ if (ret) {
+ if (ret == 1)
+@@ -3149,21 +3140,11 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
+ * rt_waiter. Also see the WARN in wake_futex_pi().
+ */
+ raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+- /*
+- * Magic trickery for now to make the RT migrate disable
+- * logic happy. The following spin_unlock() happens with
+- * interrupts disabled so the internal migrate_enable()
+- * won't undo the migrate_disable() which was issued when
+- * locking hb->lock.
+- */
+- migrate_disable();
+ spin_unlock(&hb->lock);
+
+ /* drops pi_state->pi_mutex.wait_lock */
+ ret = wake_futex_pi(uaddr, uval, pi_state);
+
+- migrate_enable();
+-
+ put_pi_state(pi_state);
+
+ /*