diff options
Diffstat (limited to 'debian/patches-rt/futex-workaround-migrate_disable-enable-in-different.patch')
-rw-r--r-- | debian/patches-rt/futex-workaround-migrate_disable-enable-in-different.patch | 61 |
1 files changed, 0 insertions, 61 deletions
diff --git a/debian/patches-rt/futex-workaround-migrate_disable-enable-in-different.patch b/debian/patches-rt/futex-workaround-migrate_disable-enable-in-different.patch deleted file mode 100644 index c9f5d342b..000000000 --- a/debian/patches-rt/futex-workaround-migrate_disable-enable-in-different.patch +++ /dev/null @@ -1,61 +0,0 @@ -From: Thomas Gleixner <tglx@linutronix.de> -Date: Wed, 8 Mar 2017 14:23:35 +0100 -Subject: [PATCH] futex: workaround migrate_disable/enable in different context -Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.0/older/patches-5.0.10-rt7.tar.xz - -migrate_disable()/migrate_enable() takes a different path in atomic() vs -!atomic() context. These little hacks ensure that we don't underflow / overflow -the migrate code counts properly while we lock the hb lockwith interrupts -enabled and unlock it with interrupts disabled. - -Signed-off-by: Thomas Gleixner <tglx@linutronix.de> -Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> ---- - kernel/futex.c | 18 ++++++++++++++++++ - 1 file changed, 18 insertions(+) - ---- a/kernel/futex.c -+++ b/kernel/futex.c -@@ -2867,6 +2867,14 @@ static int futex_lock_pi(u32 __user *uad - * 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 -@@ -2875,6 +2883,7 @@ static int futex_lock_pi(u32 __user *uad - */ - 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) -@@ -3023,10 +3032,19 @@ static int futex_unlock_pi(u32 __user *u - * 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); - |