[glibc] elf: Call free from base namespace on error in dl-libc.c [BZ #27646]

[Florian Weimer <fw@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=832f50be6c9c010e46180d14126bbb81f35e808c

commit 832f50be6c9c010e46180d14126bbb81f35e808c
Author: Florian Weimer <fweimer@redhat.com>
Date:   Tue Jul 6 13:22:01 2021 +0200

    elf: Call free from base namespace on error in dl-libc.c [BZ #27646]
    
    In dlerror_run, free corresponds to the local malloc in the
    namespace, but GLRO (dl_catch_error) uses the malloc from the base
    namespace.  elf/tst-dlmopen-gethostbyname triggers this mismatch,
    but it does not crash, presumably because of a fastbin deallocation.
    
    Fixes commit c2059edce20c124d1a99f1a94cc52e83b77a917a ("elf: Use
    _dl_catch_error from base namespace in dl-libc.c [BZ #27646]") and
    commit b2964eb1d9a6b8ab1250e8a881cf406182da5875 ("dlfcn: Failures
    after dlmopen should not terminate process [BZ #24772]").

Diff:
---
 elf/dl-libc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/elf/dl-libc.c b/elf/dl-libc.c
index a49df22029..ba792e9589 100644
--- a/elf/dl-libc.c
+++ b/elf/dl-libc.c
@@ -48,7 +48,7 @@ dlerror_run (void (*operate) (void *), void *args)
 		?: last_errstring != NULL);
 
   if (result && malloced)
-    free ((char *) last_errstring);
+    GLRO (dl_error_free) ((char *) last_errstring);
 
   return result;
 }