From: Wilco Dijkstra <wilco.dijkstra@arm.com>
Date: Fri, 10 Jun 2022 12:33:26 +0000 (+0100)
Subject: libio: Avoid RMW of flags2 outside lock (BZ #27842)
X-Git-Tag: glibc-2.36~158
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f107b7b30d815f191181617e2c14f21e6af4ddcf;p=thirdparty%2Fglibc.git

libio: Avoid RMW of flags2 outside lock (BZ #27842)

Remove an unconditional RMW on flags2 in flockfile - we don't need to change
_IO_FLAGS2_NEED_LOCK since it isn't used in flockfile or funlockfile.
This fixes BZ #27842.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
---

diff --git a/stdio-common/flockfile.c b/stdio-common/flockfile.c
index a5decb450f8..49f72c69ab7 100644
--- a/stdio-common/flockfile.c
+++ b/stdio-common/flockfile.c
@@ -22,7 +22,6 @@
 void
 __flockfile (FILE *stream)
 {
-  stream->_flags2 |= _IO_FLAGS2_NEED_LOCK;
   _IO_lock_lock (*stream->_lock);
 }
 weak_alias (__flockfile, flockfile);