From patchwork Mon Jun 23 10:09:32 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hui Zhu X-Patchwork-Id: 1659 Received: (qmail 14960 invoked by alias); 23 Jun 2014 10:10:34 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 14949 invoked by uid 89); 23 Jun 2014 10:10:32 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.2 required=5.0 tests=AWL, BAYES_40 autolearn=ham version=3.3.2 X-HELO: relay1.mentorg.com Received: from relay1.mentorg.com (HELO relay1.mentorg.com) (192.94.38.131) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 23 Jun 2014 10:10:02 +0000 Received: from svr-orw-exc-10.mgc.mentorg.com ([147.34.98.58]) by relay1.mentorg.com with esmtp id 1Wz1CI-0005WJ-Us from Hui_Zhu@mentor.com for gdb-patches@sourceware.org; Mon, 23 Jun 2014 03:09:58 -0700 Received: from SVR-ORW-FEM-04.mgc.mentorg.com ([147.34.97.41]) by SVR-ORW-EXC-10.mgc.mentorg.com with Microsoft SMTPSVC(6.0.3790.4675); Mon, 23 Jun 2014 03:09:57 -0700 Received: from localhost (147.34.91.1) by svr-orw-fem-04.mgc.mentorg.com (147.34.97.41) with Microsoft SMTP Server id 14.2.247.3; Mon, 23 Jun 2014 03:09:32 -0700 From: Hui Zhu To: gdb-patches ml Subject: [PATCH] Fix crash of gdbserver when kill threads MIME-Version: 1.0 Message-ID: <510f2362-8d33-4c3c-9a13-5d187f26abdf@SVR-ORW-FEM-04.mgc.mentorg.com> Date: Mon, 23 Jun 2014 03:09:32 -0700 X-IsSubscribed: yes gdbserver :1234 gdb.base/watch_thread_num gdb gdb.base/watch_thread_num (gdb) b 48 Breakpoint 1 at 0x400737: file ../../../binutils-gdb/gdb/testsuite/gdb.base/watch_thread_num.c, line 48. (gdb) c Continuing. Breakpoint 1, main () at ../../../binutils-gdb/gdb/testsuite/gdb.base/watch_thread_num.c:48 48 thread_result = thread_function ((void *) i); (gdb) k Kill the program being debugged? (y or n) y gdbserver :1234 gdb.base/watch_thread_num Process gdb.base/watch_thread_num created; pid = 9719 Listening on port 1234 Remote debugging from host 127.0.0.1 Killing all inferiors Segmentation fault (core dumped) Backtrace: (gdb) bt #0 find_inferior (list=, func=func@entry=0x423990 , arg=arg@entry=0x7fffe97405dc) at ../../../binutils-gdb/gdb/gdbserver/inferiors.c:199 #1 0x0000000000425bff in linux_kill (pid=10130) at ../../../binutils-gdb/gdb/gdbserver/linux-low.c:966 #2 0x000000000040ae8c in kill_inferior_callback (entry=) at ../../../binutils-gdb/gdb/gdbserver/server.c:2934 #3 0x0000000000405c61 in for_each_inferior (list=, action=action@entry=0x40ae60 ) at ../../../binutils-gdb/gdb/gdbserver/inferiors.c:57 #4 0x000000000040d5e2 in process_serial_event () at ../../../binutils-gdb/gdb/gdbserver/server.c:3767 #5 handle_serial_event (err=, client_data=) at ../../../binutils-gdb/gdb/gdbserver/server.c:3880 #6 0x0000000000412cda in handle_file_event (event_file_desc=event_file_desc@entry=4) at ../../../binutils-gdb/gdb/gdbserver/event-loop.c:434 #7 0x000000000041357a in process_event () at ../../../binutils-gdb/gdb/gdbserver/event-loop.c:189 #8 start_event_loop () at ../../../binutils-gdb/gdb/gdbserver/event-loop.c:552 #9 0x0000000000403088 in main (argc=3, argv=0x7fffe9740938) at ../../../binutils-gdb/gdb/gdbserver/server.c:3283 The cause of this issue is when linux_kill call "find_inferior (&all_threads, kill_one_lwp_callback , &pid)" to kill all the lwp of pid. In linux_wait_for_event, it will delete_lwp any lwp in all_threads if it get exit event of it. Then it make find_inferior crash. I make a patch that let kill_one_lwp_callback return 1, then after linux_wait_for_event is called(Maybe all_threads is changed), find_inferior will return. And change call "find_inferior (&all_threads, kill_one_lwp_callback , &pid)" to be a loop. It will stop when all_threads doesn't have any lwp is pid. It pass regression test in x86_64 Linux. Thanks, Hui 2014-06-23 Hui Zhu * linux-low.c (kill_one_lwp_callback): Change last return to 1. (linux_kill): Call find_inferior with a loop. --- a/gdb/gdbserver/linux-low.c +++ b/gdb/gdbserver/linux-low.c @@ -944,7 +944,9 @@ kill_one_lwp_callback (struct inferior_l pid = linux_wait_for_event (thread->entry.id, &wstat, __WALL); } while (pid > 0 && WIFSTOPPED (wstat)); - return 0; + /* Let find_inferior return because maybe other lwp in the list will + be deleted by delete_lwp. */ + return 1; } static int @@ -963,7 +965,9 @@ linux_kill (int pid) first, as PTRACE_KILL will not work otherwise. */ stop_all_lwps (0, NULL); - find_inferior (&all_threads, kill_one_lwp_callback , &pid); + /* Keep call kill_one_lwp_callback until find_inferior cannot find any + lwps that is for pid. */ + while (find_inferior (&all_threads, kill_one_lwp_callback , &pid) != NULL); /* See the comment in linux_kill_one_lwp. We did not kill the first thread in the list, so do so now. */