From: DJ Delorie <dj@delorie.com>
Date: Thu, 21 Jul 2016 01:18:10 +0000 (-0400)
Subject: Add note about the timing of recording an mremap event.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9c879c0b3140f891ac783e009d49ff8a907fcb9a;p=thirdparty%2Fglibc.git

Add note about the timing of recording an mremap event.
---

diff --git a/malloc/malloc.c b/malloc/malloc.c
index bc3f11740c8..97537311741 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -3736,6 +3736,13 @@ __libc_realloc (void *oldmem, size_t bytes)
       void *newmem;
 
 #if HAVE_MREMAP
+      /* There is no time when we own both the old and new pointers
+	 here, so we have no choice but to record the trace event in a
+	 way that might lead to an inversion.  This is a rare enough
+	 case that a double inversion is too likely to worry about,
+	 and the trace converter can fix a lone single inversion.  We
+	 choose to record it inside the 'if' because it's convient to
+	 us.  */
       newp = mremap_chunk (oldp, nb);
       if (newp)
 	{