Changeset 57322 in vbox

Timestamp:

Aug 13, 2015 1:22:09 PM (9 years ago)

Author:

vboxsync

Message:

spinlock-r0drv-linux.c: Fixed saving and restoring EFLAGS.AC, must do it when calling both spin_unlock variants as they may perhaps preempt. Also making sure it's not messed up when acquiring the lock, just for good measure.

File:

• trunk/src/VBox/Runtime/r0drv/linux/spinlock-r0drv-linux.c (modified) (4 diffs)

trunk/src/VBox/Runtime/r0drv/linux/spinlock-r0drv-linux.c

@@ -132 +132 @@
     AssertMsg(pThis && pThis->u32Magic == RTSPINLOCK_MAGIC,
               ("pThis=%p u32Magic=%08x\n", pThis, pThis ? (int)pThis->u32Magic : 0));
+    IPRT_LINUX_SAVE_EFL_AC();
 
 #ifdef CONFIG_PROVE_LOCKING
@@ -143 +144 @@
     }
     else
-    {
-        IPRT_LINUX_SAVE_EFL_AC();
         spin_lock(&pThis->Spinlock);
-        IPRT_LINUX_RESTORE_EFL_ONLY_AC();
-    }
 #ifdef CONFIG_PROVE_LOCKING
     lockdep_on();
 #endif
 
+    IPRT_LINUX_RESTORE_EFL_ONLY_AC();
     RT_ASSERT_PREEMPT_CPUID_SPIN_ACQUIRED(pThis);
 }
@@ -164 +162 @@
               ("pThis=%p u32Magic=%08x\n", pThis, pThis ? (int)pThis->u32Magic : 0));
     RT_ASSERT_PREEMPT_CPUID_SPIN_RELEASE(pThis);
+    IPRT_LINUX_SAVE_EFL_AC();           /* spin_unlock* may preempt and trash eflags.ac. */
 
 #ifdef CONFIG_PROVE_LOCKING
@@ -175 +174 @@
     }
     else
-    {
-        IPRT_LINUX_SAVE_EFL_AC();
         spin_unlock(&pThis->Spinlock);
-        IPRT_LINUX_RESTORE_EFL_ONLY_AC();
-    }
 #ifdef CONFIG_PROVE_LOCKING
     lockdep_on();
 #endif
 
+    IPRT_LINUX_RESTORE_EFL_ONLY_AC();
     RT_ASSERT_PREEMPT_CPUID();
 }