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[binutils-gdb] PR remote/19496, interrupted syscall in forking-threads-plus-bkpt
- From: Don Breazeal <donb at sourceware dot org>
- To: gdb-cvs at sourceware dot org
- Date: 16 Mar 2016 22:17:06 -0000
- Subject: [binutils-gdb] PR remote/19496, interrupted syscall in forking-threads-plus-bkpt
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=7868401b7b63d851eea5de3b780591238d579bd1
commit 7868401b7b63d851eea5de3b780591238d579bd1
Author: Don Breazeal <donb@codesourcery.com>
Date: Wed Mar 16 15:13:44 2016 -0700
PR remote/19496, interrupted syscall in forking-threads-plus-bkpt
This patch addresses "fork:Interrupted system call" (or wait:) failures
in gdb.threads/forking-threads-plus-breakpoint.exp.
The test program spawns ten threads, each of which do ten fork/waitpid
sequences. The cause of the problem was that when one of the fork
children exited before the corresponding fork parent could initiate its
waitpid for that child, a SIGCHLD and/or SIGSTOP was delivered and
interrupted a fork or waitpid in another thread.
The fix was to wrap the system calls in a loop to retry the call if
it was interrupted, like:
do
{
pid = fork ();
}
while (pid == -1 && errno == EINTR);
Since this is a Linux-only test I figure it is OK to use errno and EINTR.
I tried a number of alternative fixes using SIG_IGN, SA_RESTART,
pthread_sigblock, and bsd_signal, but none of these worked as well.
Tested on Nios II Linux target with x86 Linux host.
gdb/testsuite/ChangeLog:
2016-03-16 Don Breazeal <donb@codesourcery.com>
* gdb.threads/forking-threads-plus-breakpoint.c (thread_forks):
Retry fork and waitpid on interrupted system call errors.
* gdb.threads/forking-threads-plus-breakpoint.exp: (do_test):
Use with_timeout_factor to increase timeout to 90.
Diff:
---
gdb/testsuite/ChangeLog | 7 ++++++
.../gdb.threads/forking-threads-plus-breakpoint.c | 14 ++++++++++--
.../forking-threads-plus-breakpoint.exp | 26 ++++++++++++----------
3 files changed, 33 insertions(+), 14 deletions(-)
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index aa5422b..62413b7 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2016-03-16 Don Breazeal <donb@codesourcery.com>
+
+ * gdb.threads/forking-threads-plus-breakpoint.c (thread_forks):
+ Retry fork and waitpid on interrupted system call errors.
+ * gdb.threads/forking-threads-plus-breakpoint.exp (do_test):
+ Use with_timeout_factor to increase timeout by factor of 10.
+
2016-03-15 Don Breazeal <donb@codesourcery.com>
* gdb.cp/scope-err.cc: New test program.
diff --git a/gdb/testsuite/gdb.threads/forking-threads-plus-breakpoint.c b/gdb/testsuite/gdb.threads/forking-threads-plus-breakpoint.c
index fc64d93..c169e18 100644
--- a/gdb/testsuite/gdb.threads/forking-threads-plus-breakpoint.c
+++ b/gdb/testsuite/gdb.threads/forking-threads-plus-breakpoint.c
@@ -22,6 +22,7 @@
#include <sys/types.h>
#include <sys/wait.h>
#include <stdlib.h>
+#include <errno.h>
/* Number of threads. Each thread continuously spawns a fork and wait
for it. If we have another thread continuously start a step over,
@@ -49,14 +50,23 @@ thread_forks (void *arg)
{
pid_t pid;
- pid = fork ();
+ do
+ {
+ pid = fork ();
+ }
+ while (pid == -1 && errno == EINTR);
if (pid > 0)
{
int status;
/* Parent. */
- pid = waitpid (pid, &status, 0);
+ do
+ {
+ pid = waitpid (pid, &status, 0);
+ }
+ while (pid == -1 && errno == EINTR);
+
if (pid == -1)
{
perror ("wait");
diff --git a/gdb/testsuite/gdb.threads/forking-threads-plus-breakpoint.exp b/gdb/testsuite/gdb.threads/forking-threads-plus-breakpoint.exp
index 3d8b308..364c5d4 100644
--- a/gdb/testsuite/gdb.threads/forking-threads-plus-breakpoint.exp
+++ b/gdb/testsuite/gdb.threads/forking-threads-plus-breakpoint.exp
@@ -115,18 +115,20 @@ proc do_test { cond_bp_target detach_on_fork displaced } {
set fork_count 0
set ok 0
- set test "inferior 1 exited"
- gdb_test_multiple "" $test {
- -re "Inferior 1 \(\[^\r\n\]+\) exited normally" {
- set ok 1
- pass $test
- }
- -re "Inferior $decimal \(\[^\r\n\]+\) exited normally" {
- incr fork_count
- if {$fork_count <= 100} {
- exp_continue
- } else {
- fail "$test (too many forks)"
+ with_timeout_factor 10 {
+ set test "inferior 1 exited"
+ gdb_test_multiple "" $test {
+ -re "Inferior 1 \(\[^\r\n\]+\) exited normally" {
+ set ok 1
+ pass $test
+ }
+ -re "Inferior $decimal \(\[^\r\n\]+\) exited normally" {
+ incr fork_count
+ if {$fork_count <= 100} {
+ exp_continue
+ } else {
+ fail "$test (too many forks)"
+ }
}
}
}