[tip:perf/urgent] perf record: Fix eternal wait for stillborn child

tip-bot for Arnaldo Carvalho de Melo
2010-12-07T07:08:25Z

Commit-ID: 18483b81ee7e70ee68d4b18be618be5cfcc0b290
Gitweb: http://git.kernel.org/tip/18483b81ee7e70ee68d4b18be618be5cfcc0b290
Author: Arnaldo Carvalho de Melo <acme@redhat.com>
AuthorDate: Mon, 6 Dec 2010 15:13:38 -0200
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 6 Dec 2010 15:13:38 -0200

perf record: Fix eternal wait for stillborn child

When execvp fails to find the specified command on the path we won't get
SIGCHLD, so send a SIGUSR1 and exit right away.

Current situation would require a SIGINT performed by the user and would
produce meaningless summary.

Now:

[acme@emilia linux]$ ./foo
-bash: ./foo: No such file or directory
[acme@emilia linux]$ perf record ./foo
./foo: No such file or directory
[acme@emilia linux]$

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-record.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index e2c2de2..564491f 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -197,7 +197,7 @@ static void sig_atexit(void)
if (child_pid > 0)
kill(child_pid, SIGTERM);

- if (signr == -1)
+ if (signr == -1 || signr == SIGUSR1)
return;

signal(signr, SIG_DFL);
@@ -515,6 +515,7 @@ static int __cmd_record(int argc, const char **argv)
atexit(sig_atexit);
signal(SIGCHLD, sig_handler);
signal(SIGINT, sig_handler);
+ signal(SIGUSR1, sig_handler);

if (forks && (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0)) {
perror("failed to create pipes");
@@ -606,6 +607,7 @@ static int __cmd_record(int argc, const char **argv)
execvp(argv[0], (char **)argv);

perror(argv[0]);
+ kill(getppid(), SIGUSR1);
exit(-1);
}

@@ -762,7 +764,7 @@ static int __cmd_record(int argc, const char **argv)
}
}

- if (quiet)
+ if (quiet || signr == SIGUSR1)
return 0;

fprintf(stderr, "[ perf record: Woken up %ld times to write data ]\n", waking);