Changeset 759ea0d in mainline for kernel/generic/src/synch/futex.c

Timestamp:

2014-11-23T10:09:32Z (10 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

235d31d

Parents:

21373712

Message:

Lock futex_ht_lock spinlock after page_table_lock()

The current locking order triggers a kernel assertion on sparc64/sun4v,
because the global page table mutex is being locked when the
futex_ht_lock spinlock is held. The locking order therefore needs to be
changed so that the mutex is acquired before the spinlock.

File:

• kernel/generic/src/synch/futex.c (modified) (2 diffs)

kernel/generic/src/synch/futex.c

@@ -288 +288 @@
 static bool find_futex_paddr(uintptr_t uaddr, uintptr_t *paddr)
 {
+        page_table_lock(AS, false);
         spinlock_lock(&futex_ht_lock);
-        page_table_lock(AS, false);
 
         bool found = false;
@@ -299 +299 @@
         }
         
+        spinlock_unlock(&futex_ht_lock);
         page_table_unlock(AS, false);
-        spinlock_unlock(&futex_ht_lock);
         
         return found;