From: Pedro Alves Date: Wed, 22 Jul 2015 17:01:46 +0000 (+0100) Subject: PR threads/18600: Inferiors left around after fork+thread spawn X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=69dde7dcb81f6baf2b823dcc03e040c29ee5de7d;p=binutils-gdb.git PR threads/18600: Inferiors left around after fork+thread spawn The new gdb.threads/fork-plus-threads.exp test exposes one more problem. When one types "info inferiors" after running the program, one see's a couple inferior left still, while there should only be inferior #1 left. E.g.: (gdb) info inferiors Num Description Executable 4 process 8393 /home/pedro/bugs/src/test 2 process 8388 /home/pedro/bugs/src/test * 1 /home/pedro/bugs/src/test (gdb) info threads Calling prune_inferiors() manually at this point (from a top gdb) does not remove them, because they still have inf->pid != 0 (while they shouldn't). This suggests that we never mourned those inferiors. Enabling logs (master + previous patch) we see: ... WL: waitpid Thread 0x7ffff7fc2740 (LWP 9513) received Trace/breakpoint trap (stopped) WL: Handling extended status 0x03057f LHEW: Got clone event from LWP 9513, new child is LWP 9579 [New Thread 0x7ffff37b8700 (LWP 9579)] WL: waitpid Thread 0x7ffff7fc2740 (LWP 9508) received 0 (exited) WL: Thread 0x7ffff7fc2740 (LWP 9508) exited. ^^^^^^^^ [Thread 0x7ffff7fc2740 (LWP 9508) exited] WL: waitpid Thread 0x7ffff7fc2740 (LWP 9499) received 0 (exited) WL: Thread 0x7ffff7fc2740 (LWP 9499) exited. [Thread 0x7ffff7fc2740 (LWP 9499) exited] RSRL: resuming stopped-resumed LWP Thread 0x7ffff37b8700 (LWP 9579) at 0x3615ef4ce1: step=0 ... (gdb) info inferiors Num Description Executable 5 process 9508 /home/pedro/bugs/src/test ^^^^ 4 process 9503 /home/pedro/bugs/src/test 3 process 9500 /home/pedro/bugs/src/test 2 process 9499 /home/pedro/bugs/src/test * 1 /home/pedro/bugs/src/test (gdb) ... Note the "Thread 0x7ffff7fc2740 (LWP 9508) exited." line. That's this in wait_lwp: /* Check if the thread has exited. */ if (WIFEXITED (status) || WIFSIGNALED (status)) { thread_dead = 1; if (debug_linux_nat) fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n", target_pid_to_str (lp->ptid)); } } That was the leader thread reporting an exit, meaning the whole process is gone. So the problem is that this code doesn't understand that an WIFEXITED status of the leader LWP should be reported to infrun as process exit. gdb/ChangeLog: 2015-07-30 Pedro Alves PR threads/18600 * linux-nat.c (wait_lwp): Report to the core when thread group leader exits. gdb/testsuite/ChangeLog: 2015-07-30 Pedro Alves PR threads/18600 * gdb.threads/fork-plus-threads.exp: Test that "info inferiors" only shows inferior 1. --- diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 40403f9c900..64fbe8e55b9 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2015-07-30 Pedro Alves + + PR threads/18600 + * linux-nat.c (wait_lwp): Report to the core when thread group + leader exits. + 2015-07-30 Pedro Alves Simon Marchi diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c index 966c6a88e9b..69cfefcae3b 100644 --- a/gdb/linux-nat.c +++ b/gdb/linux-nat.c @@ -2274,6 +2274,20 @@ wait_lwp (struct lwp_info *lp) /* Check if the thread has exited. */ if (WIFEXITED (status) || WIFSIGNALED (status)) { + if (ptid_get_pid (lp->ptid) == ptid_get_lwp (lp->ptid)) + { + if (debug_linux_nat) + fprintf_unfiltered (gdb_stdlog, "WL: Process %d exited.\n", + ptid_get_pid (lp->ptid)); + + /* This is the leader exiting, it means the whole + process is gone. Store the status to report to the + core. Store it in lp->waitstatus, because lp->status + would be ambiguous (W_EXITCODE(0,0) == 0). */ + store_waitstatus (&lp->waitstatus, status); + return 0; + } + thread_dead = 1; if (debug_linux_nat) fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n", diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 06ca98797b0..e3126edab1c 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2015-07-30 Pedro Alves + + PR threads/18600 + * gdb.threads/fork-plus-threads.exp: Test that "info inferiors" + only shows inferior 1. + 2015-07-30 Simon Marchi Pedro Alves diff --git a/gdb/testsuite/gdb.threads/fork-plus-threads.exp b/gdb/testsuite/gdb.threads/fork-plus-threads.exp index 53d110224db..8a503ec6c84 100644 --- a/gdb/testsuite/gdb.threads/fork-plus-threads.exp +++ b/gdb/testsuite/gdb.threads/fork-plus-threads.exp @@ -60,6 +60,10 @@ proc do_test { detach_on_fork } { gdb_test "info threads" "No threads\." \ "no threads left" + + gdb_test "info inferiors" \ + "Num\[ \t\]+Description\[ \t\]+Executable\[ \t\]+\r\n\\* 1 \[^\r\n\]+" \ + "only inferior 1 left" } foreach detach_on_fork {"on" "off"} {