From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57047) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZwrcH-0004VA-VW for qemu-devel@nongnu.org; Thu, 12 Nov 2015 08:08:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZwrcD-0003Pi-SU for qemu-devel@nongnu.org; Thu, 12 Nov 2015 08:08:41 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52940) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZwrcD-0003PY-L6 for qemu-devel@nongnu.org; Thu, 12 Nov 2015 08:08:37 -0500 Date: Thu, 12 Nov 2015 13:08:32 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20151112130831.GG2754@work-vm> References: <1447165546-27784-1-git-send-email-quintela@redhat.com> <1447165546-27784-43-git-send-email-quintela@redhat.com> <20151112120443.GE2754@work-vm> <20151112122318.GF2754@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] [PULL 42/57] Page request: Consume pages off the post-copy queue List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: Amit Shah , QEMU Developers , Juan Quintela * Peter Maydell (peter.maydell@linaro.org) wrote: > abort/assert doesn't print a backtrace. > > I added some OSX backtrace-gathering/printing functions to the errorpath, > and got this: > > 0 qemu-system-x86_64 0x000000010c66d203 qemu_mutex_lock + 83 > 1 qemu-system-x86_64 0x000000010c2ac7af unqueue_page + 47 OK, it is the mutex that I added in that patch. > 2 qemu-system-x86_64 0x000000010c2ac386 get_queued_page + 54 > 3 qemu-system-x86_64 0x000000010c2ac135 > ram_find_and_save_block + 165 > 4 qemu-system-x86_64 0x000000010c2ab5a2 > ram_save_iterate + 130 > 5 qemu-system-x86_64 0x000000010c2afa2e > qemu_savevm_state_iterate + 302 > 6 qemu-system-x86_64 0x000000010c53acbb > migration_thread + 571 > 7 libsystem_pthread.dylib 0x00007fff9146c05a _pthread_body + 131 > 8 libsystem_pthread.dylib 0x00007fff9146bfd7 _pthread_body + 0 > 9 libsystem_pthread.dylib 0x00007fff914693ed thread_start + 13 > > > > > > Could you also add: > > > > diff --git a/migration/migration.c b/migration/migration.c > > index 9bd2ce7..85e5766 100644 > > --- a/migration/migration.c > > +++ b/migration/migration.c > > @@ -93,6 +93,7 @@ MigrationState *migrate_get_current(void) > > }; > > > > if (!once) { > > + fprintf(stderr,"migrate_get_current do init of current_migration %d\n", getpid()); > > qemu_mutex_init(¤t_migration.src_page_req_mutex); > > once = true; > > } > > diff --git a/migration/ram.c b/migration/ram.c > > index 4266687..72b46f2 100644 > > --- a/migration/ram.c > > +++ b/migration/ram.c > > @@ -1036,6 +1036,7 @@ static RAMBlock *unqueue_page(MigrationState *ms, ram_addr_t *offset, > > { > > RAMBlock *block = NULL; > > > > + fprintf(stderr,"unqueue_page %d\n", getpid()); > > qemu_mutex_lock(&ms->src_page_req_mutex); > > if (!QSIMPLEQ_EMPTY(&ms->src_page_requests)) { > > struct MigrationSrcPageRequest *entry = > > > > > > and make sure that the init happens before the first unqueue (you'll get > > loads of calls to unqueue). > > With that change, plus the backtracing: > > /x86_64/ahci/flush/retry: OK > /x86_64/ahci/flush/migrate: migrate_get_current do init of > current_migration 60427 > migrate_get_current do init of current_migration 60428 > unqueue_page 60427 > 0 qemu-system-x86_64 0x0000000101a751c3 qemu_mutex_lock + 83 > 1 qemu-system-x86_64 0x00000001016b4749 unqueue_page + 89 OK, so the lock I added is apparently being initialised before it's being locked, so that's good. OK, can you try a simple migration by hand outside of the test harness; just something simple like: ./bin/qemu-system-x86_64 -M pc -nographic (qemu) migrate "exec: cat > /dev/null" and the same with q35 ? Dave > 2 qemu-system-x86_64 0x00000001016b42f6 get_queued_page + 54 > 3 qemu-system-x86_64 0x00000001016b40a5 > ram_find_and_save_block + 165 > 4 qemu-system-x86_64 0x00000001016b3512 > ram_save_iterate + 130 > 5 qemu-system-x86_64 0x00000001016b79be > qemu_savevm_state_iterate + 302 > 6 qemu-system-x86_64 0x0000000101942c7b > migration_thread + 571 > 7 libsystem_pthread.dylib 0x00007fff9146c05a _pthread_body + 131 > 8 libsystem_pthread.dylib 0x00007fff9146bfd7 _pthread_body + 0 > 9 libsystem_pthread.dylib 0x00007fff914693ed thread_start + 13 > qemu: qemu_mutex_lock: Invalid argument > qemu-system-x86_64:Broken pipe > Not a migration stream > qemu-system-x86_64: load of migration failed: Invalid argument > > thanks > -- PMM -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK