PR gdb/22046: Fix T-stopped detach regression on old Linux kernels

On <=RHEL6 hosts Fedora/RHEL GDB started to 'kill -STOP' all processes it
detached.  Even those not originally T-stopped.  This is a Fedora-specific
patch which is based on upstream GDB's PROC_STATE_STOPPED state.

I believe (I did not verify) this patch did regress it:
commit d617208bb06bd461b52ce041d89f7127e3044762
Author: Pedro Alves <palves@redhat.com>
Date:   Mon Jul 25 12:42:17 2016 +0100
    linux-procfs: Introduce enum proc_state

As originally there was strstr() but now there is strcmp() and so the missing
trailing '\n' no longer matches.

The Bug was found by Michal Kolar.

Reproducibility:
$ gdb -p $PID
(gdb) quit
$ ...

Actual results:
===
RHEL6.9 x86_64 # scl enable devtoolset-7 bash
RHEL6.9 x86_64 # which gdb
/opt/rh/devtoolset-7/root/usr/bin/gdb
RHEL6.9 x86_64 # ./testcase.sh
24737 pts/0    S+     0:00 /bin/sleep 4
24737 pts/0    T+     0:00 /bin/sleep 4
RHEL6.9 x86_64 #
===

Expected results:
===
RHEL6.9 x86_64 # which gdb
/usr/bin/gdb
RHEL6.9 x86_64 # ./testcase.sh
24708 pts/0    S+     0:00 /bin/sleep 4
24708 pts/0    S+     0:00 /bin/sleep 4
./testcase.sh: line 20: kill: (24708) - No such process
RHEL6.9 x86_64 #
===

gdb/ChangeLog
2017-09-01  Jan Kratochvil  <jan.kratochvil@redhat.com>

	PR gdb/22046
	* nat/linux-procfs.c (parse_proc_status_state): Fix PROC_STATE_STOPPED
	detection.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9d153fa..44dfe5b 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2017-09-01  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+       PR gdb/22046
+       * nat/linux-procfs.c (parse_proc_status_state): Fix PROC_STATE_STOPPED
+       detection.
+
 2017-08-31  Sergio Durigan Junior  <sergiodj@redhat.com>
 
        * NEWS (Changes since GDB 8.0): Add entry mentioning new support

diff --git a/gdb/nat/linux-procfs.c b/gdb/nat/linux-procfs.c
index a12f622..cca35cb 100644 (file)
--- a/gdb/nat/linux-procfs.c
+++ b/gdb/nat/linux-procfs.c
@@ -104,10 +104,10 @@ parse_proc_status_state (const char *state)
       return PROC_STATE_TRACING_STOP;
     case 'T':
       /* Before Linux 2.6.33, tracing stop used uppercase T.  */
-      if (strcmp (state, "T (tracing stop)") == 0)
-       return PROC_STATE_TRACING_STOP;
-      else
+      if (strcmp (state, "T (stopped)\n") == 0)
        return PROC_STATE_STOPPED;
+      else /* "T (tracing stop)\n" */
+       return PROC_STATE_TRACING_STOP;
     case 'X':
       return PROC_STATE_DEAD;
     case 'Z':