From: Ilya Maximets Date: Mon, 8 Oct 2018 16:05:35 +0000 (+0300) Subject: migration: Stop postcopy fault thread before notifying X-Git-Tag: qemu-xen-4.13.0-rc1~628^2~4 X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=55d0fe8254984321a126efd8db358f754737aa63;p=qemu-xen.git migration: Stop postcopy fault thread before notifying POSTCOPY_NOTIFY_INBOUND_END handlers will remove userfault fds from the postcopy_remote_fds array which could be still in use by the fault thread. Let's stop the thread before notification to avoid possible accessing wrong memory. Fixes: 46343570c06e ("vhost+postcopy: Wire up POSTCOPY_END notify") Cc: qemu-stable@nongnu.org Signed-off-by: Ilya Maximets Message-Id: <20181008160536.6332-2-i.maximets@samsung.com> Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Maxime Coquelin Signed-off-by: Dr. David Alan Gilbert --- diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index 853d8b32ca..e5c02a32c5 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -533,6 +533,12 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis) if (mis->have_fault_thread) { Error *local_err = NULL; + /* Let the fault thread quit */ + atomic_set(&mis->fault_thread_quit, 1); + postcopy_fault_thread_notify(mis); + trace_postcopy_ram_incoming_cleanup_join(); + qemu_thread_join(&mis->fault_thread); + if (postcopy_notify(POSTCOPY_NOTIFY_INBOUND_END, &local_err)) { error_report_err(local_err); return -1; @@ -541,11 +547,6 @@ int postcopy_ram_incoming_cleanup(MigrationIncomingState *mis) if (qemu_ram_foreach_migratable_block(cleanup_range, mis)) { return -1; } - /* Let the fault thread quit */ - atomic_set(&mis->fault_thread_quit, 1); - postcopy_fault_thread_notify(mis); - trace_postcopy_ram_incoming_cleanup_join(); - qemu_thread_join(&mis->fault_thread); trace_postcopy_ram_incoming_cleanup_closeuf(); close(mis->userfault_fd);