Fix prof_{malloc,free}_sample_object() call order in prof_realloc().

Fix prof_realloc() to call prof_free_sampled_object() after calling
prof_malloc_sample_object().  Prior to this fix, if tctx and old_tctx
were the same, the tctx could have been prematurely destroyed.

2 files changed, 11 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index 95a4ac5..269d089 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -35,6 +35,9 @@ brevity.  Much more detail can be found in the git revision history:
     allocation events against concurrent prof_active changes.
   - Fix ixallocx_prof() to pass usize_max and zero to ixallocx_prof_sample() in
     the correct order.
+  - Fix prof_realloc() to call prof_free_sampled_object() after calling
+    prof_malloc_sample_object().  Prior to this fix, if tctx and old_tctx were
+    the same, the tctx could have been prematurely destroyed.
 
 * 4.0.0 (August 17, 2015)
 
diff --git a/include/jemalloc/internal/prof.h b/include/jemalloc/internal/prof.h
index c66611c..5eb5926 100644
--- a/include/jemalloc/internal/prof.h
+++ b/include/jemalloc/internal/prof.h
@@ -483,6 +483,7 @@ JEMALLOC_ALWAYS_INLINE void
 prof_realloc(tsd_t *tsd, const void *ptr, size_t usize, prof_tctx_t *tctx,
     bool prof_active, bool updated, size_t old_usize, prof_tctx_t *old_tctx)
 {
+	bool sampled, old_sampled;
 
 	cassert(config_prof);
 	assert(ptr != NULL || (uintptr_t)tctx <= (uintptr_t)1U);
@@ -501,12 +502,16 @@ prof_realloc(tsd_t *tsd, const void *ptr, size_t usize, prof_tctx_t *tctx,
 		}
 	}
 
-	if (unlikely((uintptr_t)old_tctx > (uintptr_t)1U))
-		prof_free_sampled_object(tsd, old_usize, old_tctx);
-	if (unlikely((uintptr_t)tctx > (uintptr_t)1U))
+	sampled = ((uintptr_t)tctx > (uintptr_t)1U);
+	old_sampled = ((uintptr_t)old_tctx > (uintptr_t)1U);
+
+	if (unlikely(sampled))
 		prof_malloc_sample_object(ptr, usize, tctx);
 	else
 		prof_tctx_set(ptr, usize, (prof_tctx_t *)(uintptr_t)1U);
+
+	if (unlikely(old_sampled))
+		prof_free_sampled_object(tsd, old_usize, old_tctx);
 }
 
 JEMALLOC_ALWAYS_INLINE void