From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:38896) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RqtR0-0003am-8h for qemu-devel@nongnu.org; Fri, 27 Jan 2012 16:34:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RqtQy-00008x-LX for qemu-devel@nongnu.org; Fri, 27 Jan 2012 16:34:14 -0500 Received: from v220110690675601.yourvserver.net ([78.47.199.172]:56484) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RqtQy-00008p-CU for qemu-devel@nongnu.org; Fri, 27 Jan 2012 16:34:12 -0500 Message-ID: <4F231851.4070708@weilnetz.de> Date: Fri, 27 Jan 2012 22:34:09 +0100 From: Stefan Weil MIME-Version: 1.0 References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------020500040609080105000508" Subject: Re: [Qemu-devel] [PATCH] Init win32 CRITICAL_SECTION before starting thread; crash when attaching disks List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Bogdan Harjoc Cc: qemu-devel@nongnu.org This is a multi-part message in MIME format. --------------020500040609080105000508 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Am 29.12.2011 18:29, schrieb Bogdan Harjoc: > Git commit 8d3bc51 crashes on win32 on startup because > qemu_tcg_init_vcpu calls: > > qemu_thread_create(th, qemu_tcg_cpu_thread_fn, ... > ... > qemu_thread_get_handle(th) > > which locks th->data->cs, a CRITICAL_SECTION which is initialized only > in the thread_fn, so it finds garbage. > > Attached patch initializes it before calling _beginthreadex. > GDB/windbg probably start newly created threads sooner, because this > doesn't happen under a debugger. > > With the patch below it boots until it crashes somewhere while > attaching disks (-hda raw_img). > > "bt" in gdb only returns "#0 0x00000000 in ??" and generate-core-file > didn't work. > > Cheers, > > diff -du qemu-8d3bc51\qemu-thread-win32.c > qemu-8d3bc51-new\qemu-thread-win32.c > --- qemu-8d3bc51\qemu-thread-win32.c Tue Dec 27 17:28:58 2011 > +++ qemu-8d3bc51-new\qemu-thread-win32.c Thu Dec 29 18:59:50 2011 > @@ -215,8 +215,6 @@ > if (data->mode == QEMU_THREAD_DETACHED) { > g_free(data); > data = NULL; > - } else { > - InitializeCriticalSection(&data->cs); > } > TlsSetValue(qemu_thread_tls_index, data); > qemu_thread_exit(start_routine(thread_arg)); > @@ -287,6 +285,10 @@ > data->arg = arg; > data->mode = mode; > data->exited = false; > + > + if (data->mode != QEMU_THREAD_DETACHED) { > + InitializeCriticalSection(&data->cs); > + } > > hThread = (HANDLE) _beginthreadex(NULL, 0, win32_start_routine, > data, 0, &thread->tid); > Tested-by: Stefan Weil Hi Bogdan, I can confirm that your patch fixes a crash which otherwise makes QEMU unusable on Windows hosts. Could you please sign your patch with a Signed-off-by line including your name and e-mail address (similar to my Tested-by above)? We need this before we can commit your patch to QEMU master. See http://wiki.qemu.org/Contribute/SubmitAPatch for more information. Please contact me if you need more information. Regards, Stefan --------------020500040609080105000508 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Am 29.12.2011 18:29, schrieb Bogdan Harjoc:
Git commit 8d3bc51 crashes on win32 on startup because qemu_tcg_init_vcpu calls:

qemu_thread_create(th, qemu_tcg_cpu_thread_fn, ...
...
qemu_thread_get_handle(th)

which locks th->data->cs, a CRITICAL_SECTION which is initialized only in the thread_fn, so it finds garbage.

Attached patch initializes it before calling _beginthreadex. GDB/windbg probably start newly created threads sooner, because this doesn't happen under a debugger.

With the patch below it boots until it crashes somewhere while attaching disks (-hda raw_img).

"bt" in gdb only returns "#0  0x00000000 in ??" and generate-core-file didn't work.

Cheers,

diff -du qemu-8d3bc51\qemu-thread-win32.c qemu-8d3bc51-new\qemu-thread-win32.c
--- qemu-8d3bc51\qemu-thread-win32.c    Tue Dec 27 17:28:58 2011
+++ qemu-8d3bc51-new\qemu-thread-win32.c    Thu Dec 29 18:59:50 2011
@@ -215,8 +215,6 @@
     if (data->mode == QEMU_THREAD_DETACHED) {
         g_free(data);
         data = NULL;
-    } else {
-        InitializeCriticalSection(&data->cs);
     }
     TlsSetValue(qemu_thread_tls_index, data);
     qemu_thread_exit(start_routine(thread_arg));
@@ -287,6 +285,10 @@
     data->arg = arg;
     data->mode = mode;
     data->exited = false;
+
+    if (data->mode != QEMU_THREAD_DETACHED) {
+        InitializeCriticalSection(&data->cs);
+    }
 
     hThread = (HANDLE) _beginthreadex(NULL, 0, win32_start_routine,
                                       data, 0, &thread->tid);


Tested-by: Stefan Weil <sw@weilnetz.de>


Hi Bogdan,

I can confirm that your patch fixes a crash which otherwise makes
QEMU unusable on Windows hosts.

Could you please sign your patch with a Signed-off-by line including
your name and e-mail address (similar to my Tested-by above)?
We need this before we can commit your patch to QEMU master.

See http://wiki.qemu.org/Contribute/SubmitAPatch for more information.

Please contact me if you need more information.

Regards,

Stefan

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