main: keep rcu_atfork callback enabled for qtest

The qtest-based fuzzer makes use of forking to reset-state between
tests. Keep the callback enabled, so the call_rcu thread gets created
within the child process.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20200220041118.23264-15-alxndr@bu.edu
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Alexander Bulekov 2020-02-19 23:11:10 -05:00 committed by Stefan Hajnoczi
parent a028edeaa6
commit d6919e4cb6

View File

@ -3782,7 +3782,17 @@ void qemu_init(int argc, char **argv, char **envp)
set_memory_options(&ram_slots, &maxram_size, machine_class);
os_daemonize();
rcu_disable_atfork();
/*
* If QTest is enabled, keep the rcu_atfork enabled, since system processes
* may be forked testing purposes (e.g. fork-server based fuzzing) The fork
* should happen before a signle cpu instruction is executed, to prevent
* deadlocks. See commit 73c6e40, rcu: "completely disable pthread_atfork
* callbacks as soon as possible"
*/
if (!qtest_enabled()) {
rcu_disable_atfork();
}
if (pid_file && !qemu_write_pidfile(pid_file, &err)) {
error_reportf_err(err, "cannot create PID file: ");