From: Szabolcs Nagy <szabolcs.nagy@arm.com>
Date: Thu, 4 Feb 2021 11:38:23 +0000 (+0000)
Subject: malloc: Simplify __mtag_tag_new_usable
X-Git-Url: https://sourceware.org/git/?a=commitdiff_plain;h=67c2661c42f047abb0863c95dd385eaa656bcb47;p=glibc.git

malloc: Simplify __mtag_tag_new_usable

The chunk cannot be a dumped one here.  The only non-obvious cases
are free and realloc which may be called on a dumped area chunk,
but in both cases it can be verified that tagging is already
avoided for dumped area chunks.

Reviewed-by: DJ Delorie <dj@redhat.com>
---

diff --git a/malloc/arena.c b/malloc/arena.c
index bf17be27d4..0777dc70c6 100644
--- a/malloc/arena.c
+++ b/malloc/arena.c
@@ -298,11 +298,6 @@ __mtag_tag_new_usable (void *ptr)
   if (ptr)
     {
       mchunkptr cp = mem2chunk(ptr);
-      /* This likely will never happen, but we can't handle retagging
-	 chunks from the dumped main arena.  So just return the
-	 existing pointer.  */
-      if (DUMPED_MAIN_ARENA_CHUNK (cp))
-	return ptr;
       ptr = __libc_mtag_tag_region (__libc_mtag_new_tag (ptr),
 				    CHUNK_AVAILABLE_SIZE (cp) - CHUNK_HDR_SZ);
     }