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fuzz: fix broken qtest check at rcu_disable_atfork 

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>
Message-Id: <20200618160516.2817-1-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Alexander Bulekov 2020-06-18 12:05:16 -04:00 committed by Thomas Huth
parent eb6490f544
commit 45222b9a90
2 changed files with 4 additions and 11 deletions
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12
softmmu/vl.c
View File

@ -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: ");

3
tests/qtest/fuzz/fuzz.c
View File

@ -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;
}