Adding debian version 4.19.249-2.debian/4.19.249-2debian

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 104 insertions, 0 deletions

diff --git a/debian/patches-rt/0069-list_bl-fixup-bogus-lockdep-warning.patch b/debian/patches-rt/0069-list_bl-fixup-bogus-lockdep-warning.patch
new file mode 100644
index 000000000..9fe3abb77
--- /dev/null
+++ b/debian/patches-rt/0069-list_bl-fixup-bogus-lockdep-warning.patch
@@ -0,0 +1,104 @@
+From 6702144cc338594e14d79ce9dd255f50d21840f9 Mon Sep 17 00:00:00 2001
+From: Josh Cartwright <joshc@ni.com>
+Date: Thu, 31 Mar 2016 00:04:25 -0500
+Subject: [PATCH 069/347] list_bl: fixup bogus lockdep warning
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz
+
+At first glance, the use of 'static inline' seems appropriate for
+INIT_HLIST_BL_HEAD().
+
+However, when a 'static inline' function invocation is inlined by gcc,
+all callers share any static local data declared within that inline
+function.
+
+This presents a problem for how lockdep classes are setup.  raw_spinlocks, for
+example, when CONFIG_DEBUG_SPINLOCK,
+
+	# define raw_spin_lock_init(lock)				\
+	do {								\
+		static struct lock_class_key __key;			\
+									\
+		__raw_spin_lock_init((lock), #lock, &__key);		\
+	} while (0)
+
+When this macro is expanded into a 'static inline' caller, like
+INIT_HLIST_BL_HEAD():
+
+	static inline INIT_HLIST_BL_HEAD(struct hlist_bl_head *h)
+	{
+		h->first = NULL;
+		raw_spin_lock_init(&h->lock);
+	}
+
+...the static local lock_class_key object is made a function static.
+
+For compilation units which initialize invoke INIT_HLIST_BL_HEAD() more
+than once, then, all of the invocations share this same static local
+object.
+
+This can lead to some very confusing lockdep splats (example below).
+Solve this problem by forcing the INIT_HLIST_BL_HEAD() to be a macro,
+which prevents the lockdep class object sharing.
+
+ =============================================
+ [ INFO: possible recursive locking detected ]
+ 4.4.4-rt11 #4 Not tainted
+ ---------------------------------------------
+ kswapd0/59 is trying to acquire lock:
+  (&h->lock#2){+.+.-.}, at: mb_cache_shrink_scan
+
+ but task is already holding lock:
+  (&h->lock#2){+.+.-.}, at:  mb_cache_shrink_scan
+
+ other info that might help us debug this:
+  Possible unsafe locking scenario:
+
+        CPU0
+        ----
+   lock(&h->lock#2);
+   lock(&h->lock#2);
+
+  *** DEADLOCK ***
+
+  May be due to missing lock nesting notation
+
+ 2 locks held by kswapd0/59:
+  #0:  (shrinker_rwsem){+.+...}, at: rt_down_read_trylock
+  #1:  (&h->lock#2){+.+.-.}, at: mb_cache_shrink_scan
+
+Reported-by: Luis Claudio R. Goncalves <lclaudio@uudg.org>
+Tested-by: Luis Claudio R. Goncalves <lclaudio@uudg.org>
+Signed-off-by: Josh Cartwright <joshc@ni.com>
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+---
+ include/linux/list_bl.h | 12 +++++++-----
+ 1 file changed, 7 insertions(+), 5 deletions(-)
+
+diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h
+index 69b659259bac..0b5de7d9ffcf 100644
+--- a/include/linux/list_bl.h
++++ b/include/linux/list_bl.h
+@@ -43,13 +43,15 @@ struct hlist_bl_node {
+ 	struct hlist_bl_node *next, **pprev;
+ };
+ 
+-static inline void INIT_HLIST_BL_HEAD(struct hlist_bl_head *h)
+-{
+-	h->first = NULL;
+ #ifdef CONFIG_PREEMPT_RT_BASE
+-	raw_spin_lock_init(&h->lock);
++#define INIT_HLIST_BL_HEAD(h)		\
++do {					\
++	(h)->first = NULL;		\
++	raw_spin_lock_init(&(h)->lock);	\
++} while (0)
++#else
++#define INIT_HLIST_BL_HEAD(h) (h)->first = NULL
+ #endif
+-}
+ 
+ static inline void INIT_HLIST_BL_NODE(struct hlist_bl_node *h)
+ {
+-- 
+2.36.1
+