Re: [LTP] [PATCH 2/2] syscalls/getcwd04.c: regression test for getcwd(2)

[Xiaoguang Wang <wangxg.fnst@cn.fujitsu.com>]

Hi,

I have run this test case in RHEL7.0GA, Fedora19, v3.11-7758-g232d2d6 and 3.16.0-rc4+.

RHEL7.0GA has this kernel bug, so this test case fails.
v3.11-7758-g232d2d6 has this bug, so this test case fails.
Fedora19 does not contain this bug, so this test case succeeds.
3.16.0-rc4+ has this bug fixed, so this test case also succeeds.

Regards,
Xiaoguang Wang

On 07/15/2014 06:13 PM, Xiaoguang Wang wrote:
> Note: this test has already been in xfstests generic/028 test case,
> I just port it to LTP.
> 
> Kernel commit '232d2d60aa5469bb097f55728f65146bd49c1d25' introduced a race
> condition that causes getcwd(2) to return "/" instead of correct path.
>     232d2d6 dcache: Translating dentry into pathname without
>             taking rename_lock
> 
> And these two kernel commits have fixed this bug:
>   ede4cebce16f5643c61aedd6d88d9070a1d23a68
>      prepend_path() needs to reinitialize dentry/vfsmount/mnt on restarts
>   f6500801522c61782d4990fa1ad96154cb397cd4
>      f650080 __dentry_path() fixes
> 
> This test is to check whether this bug exists in the running kernel,
> or whether this bug has been fixed.
> 
> Signed-off-by: Xiaoguang Wang <wangxg.fnst@cn.fujitsu.com>
> ---
>  runtest/ltplite                             |   1 +
>  runtest/stress.part3                        |   1 +
>  runtest/syscalls                            |   1 +
>  testcases/kernel/syscalls/.gitignore        |   1 +
>  testcases/kernel/syscalls/getcwd/getcwd04.c | 143 ++++++++++++++++++++++++++++
>  5 files changed, 147 insertions(+)
>  create mode 100644 testcases/kernel/syscalls/getcwd/getcwd04.c
> 
> diff --git a/runtest/ltplite b/runtest/ltplite
> index 50653a9..1457908 100644
> --- a/runtest/ltplite
> +++ b/runtest/ltplite
> @@ -275,6 +275,7 @@ getcontext01 getcontext01
>  getcwd01 getcwd01
>  getcwd02 getcwd02
>  getcwd03 getcwd03
> +getcwd04 getcwd04
>  
>  getdents01 getdents01
>  getdents02 getdents02
> diff --git a/runtest/stress.part3 b/runtest/stress.part3
> index 39ce807..368c640 100644
> --- a/runtest/stress.part3
> +++ b/runtest/stress.part3
> @@ -214,6 +214,7 @@ getcontext01 getcontext01
>  getcwd01 getcwd01
>  getcwd02 getcwd02
>  getcwd03 getcwd03
> +getcwd04 getcwd04
>  
>  getdents01 getdents01
>  getdents02 getdents02
> diff --git a/runtest/syscalls b/runtest/syscalls
> index fbed9cb..13218e3 100644
> --- a/runtest/syscalls
> +++ b/runtest/syscalls
> @@ -329,6 +329,7 @@ getcpu01 getcpu01
>  getcwd01 getcwd01
>  getcwd02 getcwd02
>  getcwd03 getcwd03
> +getcwd04 getcwd04
>  
>  getdents01 getdents01
>  getdents02 getdents02
> diff --git a/testcases/kernel/syscalls/.gitignore b/testcases/kernel/syscalls/.gitignore
> index b9d49cf..fd3282b 100644
> --- a/testcases/kernel/syscalls/.gitignore
> +++ b/testcases/kernel/syscalls/.gitignore
> @@ -273,6 +273,7 @@
>  /getcwd/getcwd01
>  /getcwd/getcwd02
>  /getcwd/getcwd03
> +/getcwd/getcwd04
>  /getdents/getdents01
>  /getdents/getdents01_64
>  /getdents/getdents02
> diff --git a/testcases/kernel/syscalls/getcwd/getcwd04.c b/testcases/kernel/syscalls/getcwd/getcwd04.c
> new file mode 100644
> index 0000000..a0285cb
> --- /dev/null
> +++ b/testcases/kernel/syscalls/getcwd/getcwd04.c
> @@ -0,0 +1,143 @@
> +/*
> + *   Copyright (c) 2014 Fujitsu Ltd.
> + *   Author: Xiaoguang Wang <wangxg.fnst@cn.fujitsu.com>
> + *
> + *   This program is free software;  you can redistribute it and/or modify
> + *   it under the terms of the GNU General Public License as published by
> + *   the Free Software Foundation; either version 2 of the License, or
> + *   (at your option) any later version.
> + *
> + *   This program is distributed in the hope that it will be useful,
> + *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
> + *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
> + *   the GNU General Public License for more details.
> + */
> +
> +/*
> + * Note: this test has already been in xfstests generic/028 test case,
> + * I just port it to LTP.
> + *
> + * Kernel commit '232d2d60aa5469bb097f55728f65146bd49c1d25' introduced a race
> + * condition that causes getcwd(2) to return "/" instead of correct path.
> + *     232d2d6 dcache: Translating dentry into pathname without
> + *             taking rename_lock
> + *
> + * And these two kernel commits fixed the bug:
> + *   ede4cebce16f5643c61aedd6d88d9070a1d23a68
> + *	prepend_path() needs to reinitialize dentry/vfsmount/mnt on restarts
> + *   f6500801522c61782d4990fa1ad96154cb397cd4
> + *	f650080 __dentry_path() fixes
> + *
> + * This test is to check whether this bug exists in the running kernel,
> + * or whether this bug has been fixed.
> + *
> + */
> +
> +#include <stdio.h>
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <sys/types.h>
> +#include <unistd.h>
> +
> +#include "usctest.h"
> +#include "test.h"
> +#include "safe_macros.h"
> +
> +#define TIMEOUT	5
> +
> +static void setup(void);
> +static void cleanup(void);
> +static void do_child(void);
> +static void sigproc(int sig);
> +static volatile sig_atomic_t end;
> +static char init_cwd[PATH_MAX];
> +
> +char *TCID = "getcwd04";
> +int TST_TOTAL = 1;
> +
> +int main(int ac, char **av)
> +{
> +	int status;
> +	const char *msg;
> +	char cur_cwd[PATH_MAX];
> +	pid_t child;
> +
> +	msg = parse_opts(ac, av, NULL, NULL);
> +	if (msg != NULL)
> +		tst_brkm(TBROK, NULL, "OPTION PARSING ERROR - %s", msg);
> +
> +	setup();
> +
> +	child = tst_fork();
> +	if (child < 0)
> +		tst_brkm(TBROK | TERRNO, cleanup, "fork failed");
> +
> +	if (child == 0)
> +		do_child();
> +
> +	 while (1) {
> +		SAFE_GETCWD(cleanup, cur_cwd, PATH_MAX);
> +		if (strncmp(init_cwd, cur_cwd, PATH_MAX)) {
> +			tst_resm(TFAIL, "initial current work directory is "
> +				 "%s, now is %s. Bug is reproduced!",
> +				 init_cwd, cur_cwd);
> +			break;
> +		}
> +
> +		if (end) {
> +			tst_resm(TPASS, "Bug is not reproduced!");
> +			break;
> +		}
> +	}
> +
> +	SAFE_KILL(cleanup, child, SIGKILL);
> +	SAFE_WAITPID(cleanup, child, &status, 0);
> +
> +	cleanup();
> +	tst_exit();
> +}
> +
> +static void setup(void)
> +{
> +	tst_sig(FORK, DEF_HANDLER, cleanup);
> +
> +	TEST_PAUSE;
> +
> +	tst_tmpdir();
> +
> +	if (signal(SIGALRM, sigproc) == SIG_ERR)
> +		tst_brkm(TBROK | TERRNO, cleanup, "signal(SIGALRM) failed");
> +
> +	alarm(TIMEOUT);
> +
> +	SAFE_MKDIR(cleanup, "testdir", 0755);
> +	SAFE_CHDIR(cleanup, "testdir");
> +
> +	SAFE_GETCWD(cleanup, init_cwd, PATH_MAX);
> +}
> +
> +static void sigproc(int sig)
> +{
> +	end = sig;
> +}
> +
> +static void do_child(void)
> +{
> +	unsigned int i = 0;
> +	char c_name[PATH_MAX] = "testfile", n_name[PATH_MAX];
> +
> +	SAFE_TOUCH(NULL, c_name, 0644, NULL);
> +
> +	while (1) {
> +		snprintf(n_name, PATH_MAX, "testfile%u", i++);
> +		SAFE_RENAME(NULL, c_name, n_name);
> +		strncpy(c_name, n_name, PATH_MAX);
> +	}
> +}
> +
> +static void cleanup(void)
> +{
> +	TEST_CLEANUP;
> +
> +	tst_rmdir();
> +}
> 


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