Revert fwalk/sfp locking to fix concurrent reads
The locking can fail in a couple of ways:
- A concurrent fread from an unbuffered or line-buffered file flushes
the output of other line-buffered files, and if _fwalk locks every
file, then the fread blocks until other file reads have completed.
- __sfp can initialize a file lock while _fwalk is locking/unlocking it.
For now, revert to the behavior Bionic had in previous releases. This
commit reverts the file locking parts of commit
468efc80da2504f4ae7de8b5e137426d44dda9d7.
Bug: http://b/131251441
Bug: http://b/130189834
Test: bionic unit tests
Change-Id: I9e20b9cd8ccd14e7962f7308e174f08af72b56c6
diff --git a/libc/stdio/refill.c b/libc/stdio/refill.c
index cfa2bfd..1df4191 100644
--- a/libc/stdio/refill.c
+++ b/libc/stdio/refill.c
@@ -40,7 +40,7 @@
lflush(FILE *fp)
{
if ((fp->_flags & (__SLBF|__SWR)) == (__SLBF|__SWR))
- return (__sflush(fp)); /* ignored... */
+ return (__sflush_locked(fp)); /* ignored... */
return (0);
}