1 files changed, 65 insertions, 0 deletions
diff --git a/debian/patches-rt/0066-lib-test_lockup-Minimum-fix-to-get-it-compiled-on-PR.patch b/debian/patches-rt/0066-lib-test_lockup-Minimum-fix-to-get-it-compiled-on-PR.patch
new file mode 100644
index 000000000..e52831303
--- /dev/null
+++ b/debian/patches-rt/0066-lib-test_lockup-Minimum-fix-to-get-it-compiled-on-PR.patch
@@ -0,0 +1,65 @@
+From 11e632bdd63b66d70c365424a1ceb502cb0c02ef Mon Sep 17 00:00:00 2001
+From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Date: Wed, 28 Oct 2020 18:55:27 +0100
+Subject: [PATCH 066/323] lib/test_lockup: Minimum fix to get it compiled on
+ PREEMPT_RT
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
+
+On PREEMPT_RT the locks are quite different so they can't be tested as
+it is done below. The alternative is test for the waitlock within
+rtmutex.
+
+This is the bare minim to get it compiled. Problems which exists on
+PREEMP_RT:
+- none of the locks (spinlock_t, rwlock_t, mutex_t, rw_semaphore) may be
+  acquired with disabled preemption or interrupts.
+  If I read the code correct the it is possible to acquire a mutex with
+  disabled interrupts.
+  I don't know how to obtain a lock pointer. Technically they are not
+  exported to userland.
+
+- memory can not be allocated with disabled premption or interrupts even
+  with GFP_ATOMIC.
+
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ lib/test_lockup.c | 16 ++++++++++++++++
+ 1 file changed, 16 insertions(+)
+
+diff --git a/lib/test_lockup.c b/lib/test_lockup.c
+index 78a630bbd03d..d27a80502204 100644
+--- a/lib/test_lockup.c
++++ b/lib/test_lockup.c
+@@ -485,6 +485,21 @@ static int __init test_lockup_init(void)
+ 		return -EINVAL;
+ 
+ #ifdef CONFIG_DEBUG_SPINLOCK
++#ifdef CONFIG_PREEMPT_RT
++	if (test_magic(lock_spinlock_ptr,
++		       offsetof(spinlock_t, lock.wait_lock.magic),
++		       SPINLOCK_MAGIC) ||
++	    test_magic(lock_rwlock_ptr,
++		       offsetof(rwlock_t, rtmutex.wait_lock.magic),
++		       SPINLOCK_MAGIC) ||
++	    test_magic(lock_mutex_ptr,
++		       offsetof(struct mutex, lock.wait_lock.magic),
++		       SPINLOCK_MAGIC) ||
++	    test_magic(lock_rwsem_ptr,
++		       offsetof(struct rw_semaphore, rtmutex.wait_lock.magic),
++		       SPINLOCK_MAGIC))
++		return -EINVAL;
++#else
+ 	if (test_magic(lock_spinlock_ptr,
+ 		       offsetof(spinlock_t, rlock.magic),
+ 		       SPINLOCK_MAGIC) ||
+@@ -498,6 +513,7 @@ static int __init test_lockup_init(void)
+ 		       offsetof(struct rw_semaphore, wait_lock.magic),
+ 		       SPINLOCK_MAGIC))
+ 		return -EINVAL;
++#endif
+ #endif
+ 
+ 	if ((wait_state != TASK_RUNNING ||
+-- 
+2.43.0
+