Fix bug 4994 hangs on read(). I have tested the patch extensibly on ARM/LT.old.

Thank you Chase Douglas for reporting it and for the patch.

1 files changed, 11 insertions, 11 deletions

diff --git a/libc/stdlib/malloc/free.c b/libc/stdlib/malloc/free.c
index da395331b..fd29690ad 100644
--- a/libc/stdlib/malloc/free.c
+++ b/libc/stdlib/malloc/free.c
@@ -22,7 +22,7 @@ libc_hidden_proto(sbrk)
 #include "heap.h"
 
 static void
-free_to_heap (void *mem, struct heap *heap)
+free_to_heap (void *mem, struct heap_free_area *heap, malloc_mutex_t *heap_lock)
 {
   size_t size;
   struct heap_free_area *fa;
@@ -39,7 +39,7 @@ free_to_heap (void *mem, struct heap *heap)
   size = MALLOC_SIZE (mem);
   mem = MALLOC_BASE (mem);
 
-  __heap_lock (heap);
+  __pthread_mutex_lock (heap_lock);
 
   /* Put MEM back in the heap, and get the free-area it was placed in.  */
   fa = __heap_free (heap, mem, size);
@@ -48,7 +48,7 @@ free_to_heap (void *mem, struct heap *heap)
      unmapped.  */
   if (HEAP_FREE_AREA_SIZE (fa) < MALLOC_UNMAP_THRESHOLD)
     /* Nope, nothing left to do, just release the lock.  */
-    __heap_unlock (heap);
+    __pthread_mutex_unlock (heap_lock);
   else
     /* Yup, try to unmap FA.  */
     {
@@ -81,7 +81,7 @@ free_to_heap (void *mem, struct heap *heap)
 	  MALLOC_DEBUG (-1, "not unmapping: 0x%lx - 0x%lx (%ld bytes)",
 			start, end, end - start);
 	  __malloc_unlock_sbrk ();
-	  __heap_unlock (heap);
+	  __pthread_mutex_unlock (heap_lock);
 	  return;
 	}
 #endif
@@ -108,7 +108,7 @@ free_to_heap (void *mem, struct heap *heap)
 #ifdef MALLOC_USE_SBRK
 
       /* Release the heap lock; we're still holding the sbrk lock.  */
-      __heap_unlock (heap);
+      __pthread_mutex_unlock (heap_lock);
       /* Lower the brk.  */
       sbrk (start - end);
       /* Release the sbrk lock too; now we hold no locks.  */
@@ -172,15 +172,15 @@ free_to_heap (void *mem, struct heap *heap)
 	      /* We have to unlock the heap before we recurse to free the mmb
 		 descriptor, because we might be unmapping from the mmb
 		 heap.  */
-	      __heap_unlock (heap);
+              __pthread_mutex_unlock (heap_lock);
 
 	      /* Release the descriptor block we used.  */
-	      free_to_heap (mmb, &__malloc_mmb_heap);
+	      free_to_heap (mmb, &__malloc_mmb_heap, &__malloc_mmb_heap_lock);
 
 	      /* Do the actual munmap.  */
 	      munmap ((void *)mmb_start, mmb_end - mmb_start);
 
-	      __heap_lock (heap);
+              __pthread_mutex_lock (heap_lock);
 
 #  ifdef __UCLIBC_HAS_THREADS__
 	      /* In a multi-threaded program, it's possible that PREV_MMB has
@@ -213,7 +213,7 @@ free_to_heap (void *mem, struct heap *heap)
 	}
 
       /* Finally release the lock for good.  */
-      __heap_unlock (heap);
+      __pthread_mutex_unlock (heap_lock);
 
       MALLOC_MMB_DEBUG_INDENT (-1);
 
@@ -243,7 +243,7 @@ free_to_heap (void *mem, struct heap *heap)
 	}
 
       /* Release the heap lock before we do the system call.  */
-      __heap_unlock (heap);
+      __pthread_mutex_unlock (heap_lock);
 
       if (unmap_end > unmap_start)
 	/* Finally, actually unmap the memory.  */
@@ -260,5 +260,5 @@ free_to_heap (void *mem, struct heap *heap)
 void
 free (void *mem)
 {
-  free_to_heap (mem, &__malloc_heap);
+  free_to_heap (mem, __malloc_heap, &__malloc_heap_lock);
 }