Changeset 2209

Timestamp:

Jul 4, 2017, 5:00:23 PM (8 years ago)

Author:

dmik

Message:

nspr: Use PM-friendly WinWaitEventSem and WinRequestMutexSem.

This avoids PM deadlocks when NSPR blocking functions are used
on a GUI thread processing PM messages. Closes #166.

Location:

nspr/trunk/pr

Files:

• include/md/_os2.h (modified) (2 diffs)
• src/md/os2/os2cv.c (modified) (2 diffs)
• src/md/os2/os2io.c (modified) (2 diffs)
• src/md/os2/os2sem.c (modified) (1 diff)
• src/md/os2/os2thred.c (modified) (2 diffs)

nspr/trunk/pr/include/md/_os2.h ¶

@@ -303 +303 @@
 #define _MD_NEW_LOCK                  (_PR_MD_NEW_LOCK)
 #define _MD_FREE_LOCK(lock)           (DosCloseMutexSem((lock)->mutex))
-#define _MD_LOCK(lock)                (DosRequestMutexSem((lock)->mutex, SEM_INDEFINITE_WAIT))
-#define _MD_TEST_AND_LOCK(lock)       (DosRequestMutexSem((lock)->mutex, SEM_INDEFINITE_WAIT),0)
+#define _MD_LOCK(lock)                (SafeRequestMutexSem((lock)->mutex, SEM_INDEFINITE_WAIT))
+#define _MD_TEST_AND_LOCK(lock)       (SafeRequestMutexSem((lock)->mutex, SEM_INDEFINITE_WAIT),0)
 #define _MD_UNLOCK                    (_PR_MD_UNLOCK)
 
@@ -488 +488 @@
 
 extern APIRET (* APIENTRY QueryThreadContext)(TID, ULONG, PCONTEXTRECORD);
+extern ULONG (* APIENTRY SafeWaitEventSem)(HEV hev, ULONG ulTimeout);
+extern ULONG (* APIENTRY SafeRequestMutexSem)(HMTX hmtx, ULONG ulTimeout);
 
 /*

nspr/trunk/pr/src/md/os2/os2cv.c ¶

@@ -246 +246 @@
 
     /* Wait for notification or timeout; don't really care which */
-    rv = DosWaitEventSem(thred->md.blocked_sema, msecs);
+    rv = SafeWaitEventSem(thred->md.blocked_sema, msecs);
     if (rv == NO_ERROR) {
         DosResetEventSem(thred->md.blocked_sema, &count);
     }
 
-    DosRequestMutexSem((lock->mutex), SEM_INDEFINITE_WAIT);
+    SafeRequestMutexSem((lock->mutex), SEM_INDEFINITE_WAIT);
 
     PR_ASSERT(rv == NO_ERROR || rv == ERROR_TIMEOUT);
@@ -287 +287 @@
             * non-signaled.  We assume this wait won't take long.
             */
-           rv = DosWaitEventSem(thred->md.blocked_sema, SEM_INDEFINITE_WAIT);
+           rv = SafeWaitEventSem(thred->md.blocked_sema, SEM_INDEFINITE_WAIT);
            if (rv == NO_ERROR) {
                DosResetEventSem(thred->md.blocked_sema, &count);

nspr/trunk/pr/src/md/os2/os2io.c ¶

@@ -34 +34 @@
     PRUint32 msecs = (ticks == PR_INTERVAL_NO_TIMEOUT) ?
         SEM_INDEFINITE_WAIT : PR_IntervalToMilliseconds(ticks);
-    rv = DosWaitEventSem(thread->md.blocked_sema, msecs);
+    rv = SafeWaitEventSem(thread->md.blocked_sema, msecs);
     DosResetEventSem(thread->md.blocked_sema, &count); 
     switch(rv) 
@@ -55 +55 @@
                      */
                     _PR_THREAD_UNLOCK(thread);
-                    rv = DosWaitEventSem(thread->md.blocked_sema, 0);
+                    rv = SafeWaitEventSem(thread->md.blocked_sema, 0);
                     DosResetEventSem(thread->md.blocked_sema, &count); 
                     PR_ASSERT(rv == NO_ERROR);

nspr/trunk/pr/src/md/os2/os2sem.c ¶

@@ -37 +37 @@
 {
     int rv;
-    rv = DosWaitEventSem(md->sem, PR_IntervalToMilliseconds(ticks));
+    rv = SafeWaitEventSem(md->sem, PR_IntervalToMilliseconds(ticks));
 
     if (rv == NO_ERROR)

nspr/trunk/pr/src/md/os2/os2thred.c ¶

@@ -12 +12 @@
 _NSPR_TLS*        pThreadLocalStorage = 0;
 _PRInterruptTable             _pr_interruptTable[] = { { 0 } };
-APIRET (* APIENTRY QueryThreadContext)(TID, ULONG, PCONTEXTRECORD);
+APIRET (* APIENTRY QueryThreadContext)(TID, ULONG, PCONTEXTRECORD) = NULL;
+ULONG (* APIENTRY SafeWaitEventSem)(HEV hev, ULONG ulTimeout) = DosWaitEventSem;
+ULONG (* APIENTRY SafeRequestMutexSem)(HMTX hmtx, ULONG ulTimeout) = DosRequestMutexSem;
 
 void
@@ -31 +33 @@
 _PR_MD_EARLY_INIT()
 {
-   HMODULE hmod;
-
-   if (DosLoadModule(NULL, 0, "DOSCALL1", &hmod) == 0)
-       DosQueryProcAddr(hmod, 877, "DOSQUERYTHREADCONTEXT",
-                        (PFN *)&QueryThreadContext);
+    HMODULE hmod;
+
+    /*
+     * TODO QueryThreadContext usage is SERIOUSLY broken because:
+     * - QueryThreadContext will remain unitialized if missing in DOSCALL1;
+     * - a call to QueryThreadContext in os2gc.c incorrectly treats its return
+     *   value as BOOL.
+     */
+    if (DosLoadModule(NULL, 0, "DOSCALL1", &hmod) == NO_ERROR)
+        DosQueryProcAddr(hmod, 877, "DOSQUERYTHREADCONTEXT",
+                         (PFN *)&QueryThreadContext);
+
+    /*
+     * Use PM-friendly variants for DosWaitEventSem and DosRequestMutexSem when
+     * they are available. This avoids blocking the entire PM when NSPR blocking
+     * APIs are called on a GUI thread that is supposed to process all incoming
+     * PM messages.
+     */
+
+    if (DosLoadModule(NULL, 0, "PMWIN", &hmod) == NO_ERROR) {
+        DosQueryProcAddr(hmod, 978, "WINWAITEVENTSEM",
+                             (PFN *)&SafeWaitEventSem);
+    }
+
+    if (DosLoadModule(NULL, 0, "PMWIN", &hmod) == NO_ERROR) {
+        DosQueryProcAddr(hmod, 979, "WINREQUESTMUTEXSEM",
+                             (PFN *)&SafeRequestMutexSem);
+    }
 }