From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51732) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zc80E-0002R0-Rt for qemu-devel@nongnu.org; Wed, 16 Sep 2015 04:23:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zc80B-0002hy-Pm for qemu-devel@nongnu.org; Wed, 16 Sep 2015 04:23:42 -0400 Received: from [59.151.112.132] (port=23661 helo=heian.cn.fujitsu.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zc80B-0002dM-6J for qemu-devel@nongnu.org; Wed, 16 Sep 2015 04:23:39 -0400 References: <55F91755.1010704@cn.fujitsu.com> <55F925AC.6060406@redhat.com> From: Wen Congyang Message-ID: <55F926E3.4010006@cn.fujitsu.com> Date: Wed, 16 Sep 2015 16:22:59 +0800 MIME-Version: 1.0 In-Reply-To: <55F925AC.6060406@redhat.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] nbd: wait all read/write requests finished when shutdowning nbd socket List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , qemu-devl Cc: Li Zhijian On 09/16/2015 04:17 PM, Paolo Bonzini wrote: > > > On 16/09/2015 09:16, Wen Congyang wrote: >> If the socket fd is shutdown, there may be some data which is received before >> shutdown. We will read the data and do read/write in nbd_trip(). But the exp's >> blk is NULL, and it will cause qemu crashed. >> >> Reported-by: Li Zhijian >> Signed-off-by: Wen Congyang >> --- >> nbd.c | 9 +++++++++ >> 1 file changed, 9 insertions(+) >> >> diff --git a/nbd.c b/nbd.c >> index 06b501b..d8586a1 100644 >> --- a/nbd.c >> +++ b/nbd.c >> @@ -1132,6 +1132,7 @@ void nbd_export_close(NBDExport *exp) >> nbd_export_set_name(exp, NULL); >> nbd_export_put(exp); >> if (exp->blk) { >> + bdrv_drain(blk_bs(exp->blk)); >> blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, >> blk_aio_detach, exp); >> blk_unref(exp->blk); > > I think a better fix is to move the whole "if" to nbd_export_put. In > fact, nbd_export_close is wrong because exp can be freed by > nbd_export_close's call to nbd_export_put. OK, I will fix it in the next version. Thanks Wen Congyang > >> @@ -1305,6 +1306,14 @@ static void nbd_trip(void *opaque) >> goto invalid_request; >> } >> >> + if (client->closing) { >> + /* >> + * The client may be closed when we are blocked in >> + * nbd_co_receive_request() >> + */ >> + goto done; >> + } > > This is okay. > > Paolo > >> switch (command) { >> case NBD_CMD_READ: >> TRACE("Request type is READ"); >> > . >