| Message ID | DB6PR0801MB18796AC2183729447CDEA9C583D49@DB6PR0801MB1879.eurprd08.prod.outlook.com |
|---|---|
| State | Committed |
| Commit | f107b7b30d815f191181617e2c14f21e6af4ddcf |
| Headers | show |
| Series | [v2] Avoid RMW of flags2 outside lock (BZ #27842) | expand |
| Context | Check | Description |
|---|---|---|
| dj/TryBot-apply_patch | success | Patch applied to master at the time it was sent |
| dj/TryBot-32bit | success | Build for i686 |
On 23/05/2022 12:47, Wilco Dijkstra wrote: > v2: remove flags2 update altogether since it isn't needed. > > 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. I think it should be ok, although POSIX states that: "All functions that reference (FILE *) objects, except those with names ending in _unlocked, shall behave as if they use flockfile() and funlockfile() internally to obtain ownership of these (FILE *) objects." Skipping the locks on single-thread case should not issue any visible side-effects (since flockfile does take the lock regardless). Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > > --- > > diff --git a/stdio-common/flockfile.c b/stdio-common/flockfile.c > index a5decb450f8d477e3105d02661282afeab58f88b..49f72c69ab7a4ccca6f21d443c6fc3a0eca76376 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);
diff --git a/stdio-common/flockfile.c b/stdio-common/flockfile.c index a5decb450f8d477e3105d02661282afeab58f88b..49f72c69ab7a4ccca6f21d443c6fc3a0eca76376 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);