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

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

[Wilco Dijkstra]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=f107b7b30d815f191181617e2c14f21e6af4ddcf

commit f107b7b30d815f191181617e2c14f21e6af4ddcf
Author: Wilco Dijkstra <wilco.dijkstra@arm.com>
Date:   Fri Jun 10 13:33:26 2022 +0100

    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:
---
 stdio-common/flockfile.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/stdio-common/flockfile.c b/stdio-common/flockfile.c
index a5decb450f..49f72c69ab 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);