[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH] fuzz: fix broken qtest check at rcu_disable_atfork
From: |
Alexander Bulekov |
Subject: |
[PATCH] fuzz: fix broken qtest check at rcu_disable_atfork |
Date: |
Thu, 18 Jun 2020 12:05:16 -0400 |
The qtest_enabled check introduced in d6919e4 always returns false, as
it is called prior to configure_accelerators(). Instead of trying to
skip rcu_disable_atfork in qemu_main, simply call rcu_enable_atfork in
the fuzzer, after qemu_main returns.
Reported-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
---
softmmu/vl.c | 12 +-----------
tests/qtest/fuzz/fuzz.c | 3 +++
2 files changed, 4 insertions(+), 11 deletions(-)
diff --git a/softmmu/vl.c b/softmmu/vl.c
index f669c06ede..95e2fed7f4 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -3832,17 +3832,7 @@ void qemu_init(int argc, char **argv, char **envp)
machine_class);
os_daemonize();
-
- /*
- * 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();
- }
+ rcu_disable_atfork();
if (pid_file && !qemu_write_pidfile(pid_file, &err)) {
error_reportf_err(err, "cannot create PID file: ");
diff --git a/tests/qtest/fuzz/fuzz.c b/tests/qtest/fuzz/fuzz.c
index a44fe479db..a36d9038e0 100644
--- a/tests/qtest/fuzz/fuzz.c
+++ b/tests/qtest/fuzz/fuzz.c
@@ -211,5 +211,8 @@ int LLVMFuzzerInitialize(int *argc, char ***argv, char
***envp)
qemu_init(result.we_wordc, result.we_wordv, NULL);
+ /* re-enable the rcu atfork, which was previously disabled in qemu_init */
+ rcu_enable_atfork();
+
return 0;
}
--
2.26.2
- [PATCH] fuzz: fix broken qtest check at rcu_disable_atfork,
Alexander Bulekov <=