ed495f0945
running nolibc-test with glibc on x86_64 got such print issue:
29 execve_root = -1 EACCES [OK]
30 fork30 fork = 0 [OK]
31 getdents64_root = 712 [OK]
The fork test case has three printf calls:
(1) llen += printf("%d %s", test, #name);
(2) llen += printf(" = %d %s ", expr, errorname(errno));
(3) llen += pad_spc(llen, 64, "[FAIL]\n"); --> vfprintf()
In the following scene, the above issue happens:
(a) The parent calls (1)
(b) The parent calls fork()
(c) The child runs and shares the print buffer of (1)
(d) The child exits, flushs the print buffer and closes its own stdout/stderr
* "30 fork" is printed at the first time.
(e) The parent calls (2) and (3), with "\n" in (3), it flushs the whole buffer
* "30 fork = 0 ..." is printed
Therefore, there are two "30 fork" in the stdout.
Between (a) and (b), if flush the stdout (and the sterr), the child in
stage (c) will not be able to 'see' the print buffer.
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.