From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEC97C433E6 for ; Tue, 2 Feb 2021 07:34:34 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0CAE764DDD for ; Tue, 2 Feb 2021 07:34:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0CAE764DDD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=ispras.ru Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:49274 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l6qCm-0006Tx-T8 for qemu-devel@archiver.kernel.org; Tue, 02 Feb 2021 02:34:32 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:46496) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l6qBp-00063I-Q0 for qemu-devel@nongnu.org; Tue, 02 Feb 2021 02:33:33 -0500 Received: from mail.ispras.ru ([83.149.199.84]:56836) by eggs.gnu.org with esmtps (TLS1.2:DHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l6qBn-0007A4-9Z for qemu-devel@nongnu.org; Tue, 02 Feb 2021 02:33:33 -0500 Received: from [192.168.0.92] (unknown [62.118.151.149]) by mail.ispras.ru (Postfix) with ESMTPSA id 574AE40D4004; Tue, 2 Feb 2021 07:33:22 +0000 (UTC) Subject: Re: [PATCH] char: don't fail when client is not connected To: =?UTF-8?Q?Marc-Andr=c3=a9_Lureau?= References: <161224971122.79781.8594358970645859667.stgit@pasha-ThinkPad-X280> From: Pavel Dovgalyuk Message-ID: <1a5d134b-c826-9620-094e-48fc6bb931b0@ispras.ru> Date: Tue, 2 Feb 2021 10:33:22 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=83.149.199.84; envelope-from=pavel.dovgalyuk@ispras.ru; helo=mail.ispras.ru X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, WEIRD_PORT=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Bonzini, Paolo" , qemu-devel Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 02.02.2021 10:27, Marc-André Lureau wrote: > Hi > > On Tue, Feb 2, 2021 at 11:18 AM Pavel Dovgalyuk > > wrote: > > This patch checks that ioc is not null before > using it in tcp socket tcp_chr_add_watch function. > > Signed-off-by: Pavel Dovgalyuk > > > > Do you have a backtrace or a reproducer when this happens? > thanks Here is the backtrace: Thread 4 "qemu-system-x86" received signal SIGSEGV, Segmentation fault. [Switching to Thread 0x7ffff2506700 (LWP 64988)] object_get_class (obj=obj@entry=0x0) at ../qom/object.c:999 999 return obj->class; (gdb) bt #0 object_get_class (obj=obj@entry=0x0) at ../qom/object.c:999 #1 0x0000555555b70e26 in QIO_CHANNEL_GET_CLASS (obj=0x0) at /home/pasha/ispras/qemu-test/include/io/channel.h:29 #2 qio_channel_create_watch (ioc=0x0, condition=(G_IO_OUT | G_IO_HUP)) at ../io/channel.c:281 #3 0x0000555555c1bf9b in qemu_chr_fe_add_watch (be=be@entry=0x555556981648, cond=cond@entry=(G_IO_OUT | G_IO_HUP), func=func@entry=0x55555597f170 , user_data=user_data@entry=0x5555569815a0) at /home/pasha/ispras/qemu-test/include/chardev/char.h:229 #4 0x000055555597f042 in serial_xmit (s=s@entry=0x5555569815a0) at ../hw/char/serial.c:265 #5 0x000055555597f437 in serial_ioport_write (opaque=0x5555569815a0, addr=, val=91, size=) at ../hw/char/serial.c:359 #6 0x0000555555ab95e0 in memory_region_write_accessor (mr=mr@entry=0x555556981700, addr=0, value=value@entry=0x7ffff2504fc8, size=size@entry=1, shift=, mask=mask@entry=255, attrs=...) at ../softmmu/memory.c:491 #7 0x0000555555ab807e in access_with_adjusted_size (addr=addr@entry=0, value=value@entry=0x7ffff2504fc8, size=size@entry=1, access_size_min=, access_size_max=, access_fn=access_fn@entry= 0x555555ab9550 , mr=0x555556981700, attrs=...) at ../softmmu/memory.c:552 #8 0x0000555555abb947 in memory_region_dispatch_write (mr=mr@entry=0x555556981700, addr=0, data=, data@entry=91, op=op@entry=MO_8, attrs=attrs@entry=...) at ../softmmu/memory.c:1501 #9 0x0000555555a721d8 in address_space_stb (as=, addr=, val=91, attrs=..., result=0x0) at /home/pasha/ispras/qemu-test/memory_ldst.c.inc:382 #10 0x00007fffa8b63022 in code_gen_buffer () #11 0x0000555555b10ab0 in cpu_tb_exec (tb_exit=, itb=, cpu=0x7fffa8635b00 ) at ../accel/tcg/cpu-exec.c:188 #12 cpu_loop_exec_tb (tb_exit=, last_tb=, tb=, cpu=0x7fffa8635b00 ) at ../accel/tcg/cpu-exec.c:700 #13 cpu_exec (cpu=cpu@entry=0x5555566b4350) at ../accel/tcg/cpu-exec.c:811 #14 0x0000555555b0ce97 in tcg_cpus_exec (cpu=cpu@entry=0x5555566b4350) at ../accel/tcg/tcg-cpus.c:57 #15 0x0000555555abfa73 in rr_cpu_thread_fn (arg=arg@entry=0x5555566b4350) at ../accel/tcg/tcg-cpus-rr.c:217 #16 0x0000555555c80573 in qemu_thread_start (args=) at ../util/qemu-thread-posix.c:521 #17 0x00007ffff6302609 in start_thread (arg=) at pthread_create.c:477 #18 0x00007ffff6229293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95 > > --- >  chardev/char-socket.c |    3 +++ >  1 file changed, 3 insertions(+) > > diff --git a/chardev/char-socket.c b/chardev/char-socket.c > index 213a4c8dd0..cef1d9438f 100644 > --- a/chardev/char-socket.c > +++ b/chardev/char-socket.c > @@ -385,6 +385,9 @@ static ssize_t tcp_chr_recv(Chardev *chr, char > *buf, size_t len) >  static GSource *tcp_chr_add_watch(Chardev *chr, GIOCondition cond) >  { >      SocketChardev *s = SOCKET_CHARDEV(chr); > +    if (!s->ioc) { > +        return NULL; > +    } >      return qio_channel_create_watch(s->ioc, cond); >  } > >