From: Sergei Trofimovich <slyich@gmail.com>
To: Ian Lance Taylor <iant@google.com>
Cc: gcc-patches@gcc.gnu.org, Ian Lance Taylor <ian@airs.com>,
Sergei Trofimovich <siarheit@google.com>
Subject: Re: [PATCH] libbacktrace: fix fd leak tests on systems with extra descriptors
Date: Fri, 13 Aug 2021 08:05:08 +0100 [thread overview]
Message-ID: <20210813080508.09afde43@zn3> (raw)
In-Reply-To: <CAKOQZ8xWJwLOvhQiywApBuW=EDU7hkQXNfHYANnnD_4rp1Bn6w@mail.gmail.com>
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On Thu, 12 Aug 2021 16:16:04 -0700
Ian Lance Taylor <iant@google.com> wrote:
> On Thu, Aug 12, 2021 at 3:34 PM Sergei Trofimovich via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
> >
> > From: Sergei Trofimovich <siarheit@google.com>
> >
> > I noticed test failures when ran gcc test suite from under mc shell.
> > mc opens fd=9 and exposes it to child processes. As a result a few
> > tests failes:
> > FAIL: b2test_buildid
> > FAIL: btest_gnudebuglink
> > FAIL: btest
> > FAIL: btest_lto
> > FAIL: btest_alloc
> > FAIL: ctestg
> > FAIL: ctesta
> > FAIL: ctestg_alloc
> > FAIL: ctesta_alloc
> > FAIL: dwarf5
> > FAIL: dwarf5_alloc
> >
> > Instead of trying to close file descripts in range test polls for
> > first available file descriptor by creating it via dup(1).
> >
> > libbacktrace/
> >
> > * btest.c (check_open_files): Use last free file descriptor as a
> > signal for flie descriptor leak.
>
> This isn't a useful replacement, as this will pass as long as
> libbacktrace closes the first file descriptor that it opens. It won't
> check whether libbacktrace left any other file descriptors open.
>
> Perhaps at program startup we could fstat descriptors up to 10 and
> record whether they are valid, and then skip those files in
> check_open_files.
Oh, great point! Completely missed it. Changed the patch to poll for present
file descriptors with fcntl(fd, F_GETFD) to compare before/after.
--
Sergei
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From dba67cc728d6be521f59a4c0d3abe7879de2db4c Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <siarheit@google.com>
Date: Thu, 12 Aug 2021 23:27:00 +0100
Subject: [PATCH v2] libbacktrace: fix fd leak tests on systems with extra
descriptors
I noticed test failures when ran gcc test suite from under mc shell.
mc opens fd=9 and exposes it to child processes. As a result a few
tests failes:
FAIL: b2test_buildid
FAIL: btest_gnudebuglink
FAIL: btest
FAIL: btest_lto
FAIL: btest_alloc
FAIL: ctestg
FAIL: ctesta
FAIL: ctestg_alloc
FAIL: ctesta_alloc
FAIL: dwarf5
FAIL: dwarf5_alloc
Instead of trying to close file descripts in range test polls for
their presence with with fcntl(fd, F_GETFD) before and after test.
libbacktrace/
* btest.c (check_open_files): Use fcntl to poll for file
descriptor presence.
---
libbacktrace/btest.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/libbacktrace/btest.c b/libbacktrace/btest.c
index 9f9c03babf3..c08c1540fa6 100644
--- a/libbacktrace/btest.c
+++ b/libbacktrace/btest.c
@@ -34,6 +34,7 @@ POSSIBILITY OF SUCH DAMAGE. */
libbacktrace library. */
#include <assert.h>
+#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -458,6 +459,18 @@ test5 (void)
return failures;
}
+#define MAX_FDS 10
+static int fd_states[MAX_FDS];
+
+static void
+store_open_files (void)
+{
+ int i;
+
+ for (i = 0; i < MAX_FDS; i++)
+ fd_states[i] = fcntl (i, F_GETFD);
+}
+
/* Check that are no files left open. */
static void
@@ -465,9 +478,9 @@ check_open_files (void)
{
int i;
- for (i = 3; i < 10; i++)
+ for (i = 0; i < MAX_FDS; i++)
{
- if (close (i) == 0)
+ if (fcntl (i, F_GETFD) != fd_states[i])
{
fprintf (stderr,
"ERROR: descriptor %d still open after tests complete\n",
@@ -484,6 +497,7 @@ main (int argc ATTRIBUTE_UNUSED, char **argv)
{
state = backtrace_create_state (argv[0], BACKTRACE_SUPPORTS_THREADS,
error_callback_create, NULL);
+ store_open_files ();
#if BACKTRACE_SUPPORTED
test1 ();
--
2.32.0
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next prev parent reply other threads:[~2021-08-13 7:05 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-12 22:33 Sergei Trofimovich
2021-08-12 23:16 ` Ian Lance Taylor
2021-08-13 7:05 ` Sergei Trofimovich [this message]
2021-08-13 16:52 ` Ian Lance Taylor
2021-08-13 22:05 ` Sergei Trofimovich
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