From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1944) id 30538386F46E; Thu, 4 Mar 2021 16:25:29 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 30538386F46E Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Szabolcs Nagy To: glibc-cvs@sourceware.org Subject: [glibc/nsz/mtag] malloc: Avoid taggig mmaped memory on free X-Act-Checkin: glibc X-Git-Author: Szabolcs Nagy X-Git-Refname: refs/heads/nsz/mtag X-Git-Oldrev: 94bbedf7f5a7005d681999061f317baae91f4056 X-Git-Newrev: 3387a579c77328cd5e793da028dd432c9a01e8b1 Message-Id: <20210304162529.30538386F46E@sourceware.org> Date: Thu, 4 Mar 2021 16:25:29 +0000 (GMT) X-BeenThere: glibc-cvs@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Glibc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 Mar 2021 16:25:29 -0000 https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=3387a579c77328cd5e793da028dd432c9a01e8b1 commit 3387a579c77328cd5e793da028dd432c9a01e8b1 Author: Szabolcs Nagy Date: Thu Feb 4 11:52:14 2021 +0000 malloc: Avoid taggig mmaped memory on free Either the memory belongs to the dumped area, in which case we don't want to tag (the dumped area has the same tag as malloc internal data so tagging is unnecessary, but chunks there may not have the right alignment for the tag granule), or the memory will be unmapped immediately (and thus tagging is not useful). Diff: --- malloc/malloc.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/malloc/malloc.c b/malloc/malloc.c index 4538a01614..b4c800bd7f 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -3284,9 +3284,6 @@ __libc_free (void *mem) p = mem2chunk (mem); - /* Mark the chunk as belonging to the library again. */ - (void)TAG_REGION (chunk2rawmem (p), CHUNK_AVAILABLE_SIZE (p) - CHUNK_HDR_SZ); - if (chunk_is_mmapped (p)) /* release mmapped memory. */ { /* See if the dynamic brk/mmap threshold needs adjusting. @@ -3307,6 +3304,10 @@ __libc_free (void *mem) { MAYBE_INIT_TCACHE (); + /* Mark the chunk as belonging to the library again. */ + (void)TAG_REGION (chunk2rawmem (p), + CHUNK_AVAILABLE_SIZE (p) - CHUNK_HDR_SZ); + ar_ptr = arena_for_chunk (p); _int_free (ar_ptr, p, 0); }