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authorAlexander Bulekov <alxndr@bu.edu>2020-02-19 23:11:10 -0500
committerStefan Hajnoczi <stefanha@redhat.com>2020-02-22 08:26:48 +0000
commitd6919e4cb65230b0c8081eb072893d4e8a191a59 (patch)
tree103b32504913231f87035418dc7cab7558794c8d
parenta028edeaa6f1c154f06e16440e46b0f876a64077 (diff)
downloadqemu-arm-d6919e4cb65230b0c8081eb072893d4e8a191a59.tar.gz
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>
-rw-r--r--softmmu/vl.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/softmmu/vl.c b/softmmu/vl.c
index 080d3b5106..92c7b3a6e9 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -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: ");