From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58094) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cTAdC-0000yl-0j for qemu-devel@nongnu.org; Mon, 16 Jan 2017 11:59:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cTAdB-00007g-4d for qemu-devel@nongnu.org; Mon, 16 Jan 2017 11:59:42 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45058) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cTAdA-00007X-S0 for qemu-devel@nongnu.org; Mon, 16 Jan 2017 11:59:41 -0500 From: Paolo Bonzini Date: Mon, 16 Jan 2017 17:59:04 +0100 Message-Id: <20170116165916.8575-21-pbonzini@redhat.com> In-Reply-To: <20170116165916.8575-1-pbonzini@redhat.com> References: <20170116165916.8575-1-pbonzini@redhat.com> Subject: [Qemu-devel] [PULL 20/32] qemu-thread: fix qemu_thread_set_name() race in qemu_thread_create() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Caoxinhua , zhanghailiang From: Caoxinhua QEMU will crash with the follow backtrace if the new created thread exited before we call qemu_thread_set_name() for it. (gdb) bt #0 0x00007f9a68b095d7 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56 #1 0x00007f9a68b0acc8 in __GI_abort () at abort.c:90 #2 0x00007f9a69cda389 in PAT_abort () from /usr/lib64/libuvpuserhotfix.so #3 0x00007f9a69cdda0d in patchIllInsHandler () from /usr/lib64/libuvpuserhotfix.so #4 #5 pthread_setname_np (th=140298470549248, name=name@entry=0x8cc74a "io-task-worker") at ../nptl/sysdeps/unix/sysv/linux/pthread_setname.c:49 #6 0x00000000007f5f20 in qemu_thread_set_name (thread=thread@entry=0x7ffd2ac09680, name=name@entry=0x8cc74a "io-task-worker") at util/qemu_thread_posix.c:459 #7 0x00000000007f679e in qemu_thread_create (thread=thread@entry=0x7ffd2ac09680, name=name@entry=0x8cc74a "io-task-worker",start_routine=start_routine@entry=0x7c1300 , arg=arg@entry=0x7f99b8001720, mode=mode@entry=1) at util/qemu_thread_posix.c:498 #8 0x00000000007c15b6 in qio_task_run_in_thread (task=task@entry=0x7f99b80033d0, worker=worker@entry=0x7bd920 , opaque=0x7f99b8003370, destroy=0x7c6220 ) at io/task.c:133 #9 0x00000000007bda04 in qio_channel_socket_connect_async (ioc=0x7f99b80014c0, addr=0x37235d0, callback=callback@entry=0x54ad00 , opaque=opaque@entry=0x38118b0, destroy=destroy@entry=0x0) at io/channel_socket.c:191 #10 0x00000000005487f6 in socket_reconnect_timeout (opaque=0x38118b0) at qemu_char.c:4402 #11 0x00007f9a6a1533b3 in g_timeout_dispatch () from /usr/lib64/libglib-2.0.so.0 #12 0x00007f9a6a15299a in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0 #13 0x0000000000747386 in glib_pollfds_poll () at main_loop.c:227 #14 0x0000000000747424 in os_host_main_loop_wait (timeout=404000000) at main_loop.c:272 #15 0x0000000000747575 in main_loop_wait (nonblocking=nonblocking@entry=0) at main_loop.c:520 #16 0x0000000000557d31 in main_loop () at vl.c:2170 #17 0x000000000041c8b7 in main (argc=, argv=, envp=) at vl.c:5083 Let's detach the new thread after calling qemu_thread_set_name(). Signed-off-by: Caoxinhua Signed-off-by: zhanghailiang Message-Id: <1483493521-9604-1-git-send-email-zhang.zhanghailiang@huawei.com> Signed-off-by: Paolo Bonzini --- util/qemu-thread-posix.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c index d20cdde..d31793d 100644 --- a/util/qemu-thread-posix.c +++ b/util/qemu-thread-posix.c @@ -481,12 +481,6 @@ void qemu_thread_create(QemuThread *thread, const char *name, if (err) { error_exit(err, __func__); } - if (mode == QEMU_THREAD_DETACHED) { - err = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); - if (err) { - error_exit(err, __func__); - } - } /* Leave signal handling to the iothread. */ sigfillset(&set); @@ -499,6 +493,12 @@ void qemu_thread_create(QemuThread *thread, const char *name, qemu_thread_set_name(thread, name); } + if (mode == QEMU_THREAD_DETACHED) { + err = pthread_detach(thread->thread); + if (err) { + error_exit(err, __func__); + } + } pthread_sigmask(SIG_SETMASK, &oldset, NULL); pthread_attr_destroy(&attr); -- 2.9.3