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From: Joshua Hudson <joshudson@gmail.com>
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Subject: Hangup calling setuid() from vfork() child
Date: Mon, 30 Sep 2019 08:29:16 -0700
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Archived-At: <http://permalink.gmane.org/gmane.linux.lib.musl.general/14752>

If there is more than one thread and vfork() calls setuid(), musl libc hangs up.

void *thfunction(void*ig) {sleep(1000);returnNULL;}

int main()
{
    pthread_t id;
    pthread_create(&id, NULL, thfunction, NULL);
    if (vfork() == 0) {
        setuid(0); /* hangup */
        _exit(0);
    }
}