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From: Jan Kiszka <jan.kiszka@siemens.com>
To: Fabian Scheler <Fabian.Scheler@siemens.com>, xenomai@lists.linux.dev
Subject: Re: [PATCH v2] testsuite/smokey/gdb: Fix race-condition
Date: Wed, 20 Mar 2024 08:40:41 +0100	[thread overview]
Message-ID: <62f6cf88-2aac-4300-8e9e-b868c42ebbf6@siemens.com> (raw)
In-Reply-To: <20240314134411.28121-2-Fabian.Scheler@siemens.com>

On 14.03.24 14:44, Fabian Scheler wrote:
> When quitting gdb by sending the quit-command, gdb may actually finish before
> the father-process calls pause. In that case the father-process would wait
> endlessly.
> 
> The fix now uses waitpid instead of pause to explicitly wait for the
> child-process, in contrast to pause waitpid also handles child-processes that
> already have been terminated.
> 
> Signed-off-by: Fabian Scheler <Fabian.Scheler@siemens.com>
> ---
>  testsuite/smokey/gdb/gdb.c | 23 +++++++++++++++--------
>  1 file changed, 15 insertions(+), 8 deletions(-)
> 
> diff --git a/testsuite/smokey/gdb/gdb.c b/testsuite/smokey/gdb/gdb.c
> index b09b78b4e..1daa7ee4c 100644
> --- a/testsuite/smokey/gdb/gdb.c
> +++ b/testsuite/smokey/gdb/gdb.c
> @@ -78,7 +78,7 @@ static void handle_sigchld(int signum)
>  	if (WEXITSTATUS(status) == ESRCH)
>  		smokey_note("gdb: skipped (gdb not available)");
>  	else
> -		check("gdb execution", WEXITSTATUS(status), 0);
> +		check("gdb terminated unexpectedly", 0, 1);
>  	child_terminated = 1;
>  	close(pipe_out[0]);
>  }
> @@ -202,6 +202,8 @@ static int run_gdb(struct smokey_test *t, int argc, char *const argv[])
>  	pthread_attr_t attr;
>  	char run_param[32];
>  	cpu_set_t cpu_set;
> +	pid_t childpid;
> +	int status;
>  	int err;
>  
>  	smokey_parse_args(t, argc, argv);
> @@ -257,7 +259,8 @@ static int run_gdb(struct smokey_test *t, int argc, char *const argv[])
>  		err = pipe(pipe_out);
>  		check_no_error("pipe_out", err);
>  
> -		switch (do_fork()) {
> +		childpid = do_fork();
> +		switch (childpid) {
>  		case -1:
>  			error(1, errno, "fork/vfork");
>  
> @@ -283,8 +286,14 @@ static int run_gdb(struct smokey_test *t, int argc, char *const argv[])
>  
>  		default:
>  			wait_for_pattern("(gdb) ");
> +
> +			/* the signal handler only is used to skip the test if
> +			   gdb is missing */
>  			if (child_terminated)
>  				break;
> +			else
> +				signal(SIGCHLD, SIG_DFL);
> +
>  			send_command("b breakpoint_target\n", 1);
>  			send_command("r\n", 1);
>  
> @@ -301,13 +310,11 @@ static int run_gdb(struct smokey_test *t, int argc, char *const argv[])
>  			eval_expression("thread_loops==expected_loops", "1");
>  
>  			send_command("q\n", 0);
> -			pause();
>  
> -			if (!child_terminated) {
> -				fprintf(stderr,
> -					"FAILURE: gdb still running?!\n");
> -				exit(1);
> -			}
> +			err = waitpid(childpid, &status, 0);
> +			check("waitpid", err, childpid);
> +			check("gdb execution", WEXITSTATUS(status), 0);
> +			close(pipe_out[0]);
>  		}
>  
>  		signal(SIGCHLD, SIG_DFL);

Thanks, applied.

Jan

-- 
Siemens AG, Technology
Linux Expert Center


      reply	other threads:[~2024-03-20  7:40 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-12  6:38 [PATCH] testsuite/smokey/gdb: Fix race-condition Fabian Scheler
2024-03-12  7:48 ` Florian Bezdeka
2024-03-12  7:59   ` Scheler, Fabian (T CED SES-DE)
2024-03-12  7:49 ` Jan Kiszka
2024-03-12  8:15   ` Scheler, Fabian (T CED SES-DE)
2024-03-14 13:44     ` [PATCH v2] " Fabian Scheler
2024-03-20  7:40       ` Jan Kiszka [this message]

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