From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44085) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YSk3P-0002Gi-EY for qemu-devel@nongnu.org; Tue, 03 Mar 2015 05:27:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YSk3M-0003Jy-Nh for qemu-devel@nongnu.org; Tue, 03 Mar 2015 05:27:55 -0500 Received: from mail-wg0-x234.google.com ([2a00:1450:400c:c00::234]:41194) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YSk3M-0003Ju-Ge for qemu-devel@nongnu.org; Tue, 03 Mar 2015 05:27:52 -0500 Received: by wghl18 with SMTP id l18so39001583wgh.8 for ; Tue, 03 Mar 2015 02:27:51 -0800 (PST) Sender: Paolo Bonzini Message-ID: <54F58CA3.2090802@redhat.com> Date: Tue, 03 Mar 2015 11:27:47 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <33183CC9F5247A488A2544077AF1902086E48F40@SZXEMA503-MBS.china.huawei.com> <54F588D7.6060804@redhat.com> In-Reply-To: <54F588D7.6060804@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [Bug ?]Qemu segfault because of non-initial kvm_state variable List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Gonglei (Arei)" , "qemu-devel@nongnu.org" On 03/03/2015 11:11, Paolo Bonzini wrote: > > > On 03/03/2015 09:01, Gonglei (Arei) wrote: >> Hi, >> >> I encountered a Qemu segfault problem in my environment. >> >> # ./qemu-system-x86_64 -enable-kvm -m 4096 -smp 4 -name redhat6.2 -drive file=/home/win2008_ent_r2_64_01,\ >> if=none,id=drive-ide0-0-0 -device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -vnc :10 >> Segmentation fault ... and here's the right fix: ------------------- 8< --------------------------- From: Paolo Bonzini Subject: [PATCH] vl: take iothread lock very early If the iothread lock isn't taken by the main thread, the RCU callbacks might run concurrently with the main thread. QEMU's not ready for that. Signed-off-by: Paolo Bonzini diff --git a/vl.c b/vl.c index 09693f5..d743727 100644 --- a/vl.c +++ b/vl.c @@ -2763,6 +2763,9 @@ int main(int argc, char **argv, char **envp) FILE *vmstate_dump_file = NULL; Error *main_loop_err = NULL; + qemu_init_cpu_loop(); + qemu_mutex_lock_iothread(); + atexit(qemu_run_exit_notifiers); error_set_progname(argv[0]); qemu_init_exec_dir(argv[0]); @@ -4098,9 +4101,6 @@ int main(int argc, char **argv, char **envp) os_set_line_buffering(); - qemu_init_cpu_loop(); - qemu_mutex_lock_iothread(); - #ifdef CONFIG_SPICE /* spice needs the timers to be initialized by this point */ qemu_spice_init();