[Xenomai-core] [PATCH] native: Properly update lockcnt on recursive call from secondary mode

[Xenomai-core] [PATCH] native: Properly update lockcnt on recursive call from secondary mode

[Jan Kiszka]

We cannot assume that only non-recursive rt_mutex_acquire calls will
happen; the application may be buggy and come from secondary mode. Make
sure to update the user space recursion counter correctly in any case so
that at least the mutex is kept in a valid state.

Signed-off-by: Jan Kiszka <jan.kiszka@domain.hid>
---

Can be pulled from 'for-upstream' as well.

 src/skins/native/mutex.c |   14 ++++++++++++++
 1 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/src/skins/native/mutex.c b/src/skins/native/mutex.c
index 29843c7..98844ef 100644
--- a/src/skins/native/mutex.c
+++ b/src/skins/native/mutex.c
@@ -96,6 +96,20 @@ static int rt_mutex_acquire_inner(RT_MUTEX *mutex, RTIME timeout, xntmode_t mode
 
 		if (timeout == TM_NONBLOCK && mode == XN_RELATIVE)
 			return -EWOULDBLOCK;
+	} else if (xnsynch_fast_owner_check(mutex->fastlock, cur) == 0) {
+		/*
+		 * The application is buggy as it jumped to secondary mode
+		 * while holding the mutex. Nevertheless, we have to keep the
+		 * mutex state consistent.
+		 *
+		 * We make no efforts to migrate or warn here. There is
+		 * CONFIG_XENO_OPT_DEBUG_SYNCH_RELAX to catch such bugs.
+		 */
+		if (mutex->lockcnt == UINT_MAX)
+			return -EAGAIN;
+
+		mutex->lockcnt++;
+		return 0;
 	}
 #endif /* CONFIG_XENO_FASTSYNCH */
 
-- 
1.6.0.2