On 29/01/2020 06.34, Bulekov, Alexander wrote: > 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 <[email protected]> > --- > vl.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/vl.c b/vl.c > index bb77935f04..cf8e2d3ebb 100644 > --- a/vl.c > +++ b/vl.c > @@ -3794,7 +3794,14 @@ 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) > + */ > + if (!qtest_enabled()) { > + rcu_disable_atfork(); > + } > > if (pid_file && !qemu_write_pidfile(pid_file, &err)) { > error_reportf_err(err, "cannot create PID file: ");
Hi Alexander, I think this patch might maybe not work as expected: The qtest_enabled() has been added before configure_accelerators() is called in main(). So qtest_enabled() should always return "false" and thus rcu_disabled_fork() is still called in any case... could you please double-check whether it works for you and I just made a mistake, or whether this is a bug indeed? Thanks, Thomas
