Question on a lockdep test case about mixed read-write ABBA

[Yuyang Du]

Hi Peter,

I observed this test case you wrote in Commit: e9149858974606
("locking/lockdep/selftests: Add mixed read-write ABBA").

static void rwsem_ABBA2(void)
{
       RSL(X1);
       ML(Y1);
       MU(Y1);
       RSU(X1);

       ML(Y1);
       RSL(X1);
       RSU(X1);
       MU(Y1); // should fail
}

Why should it fail? This is not a deadlock, right? The depencencies
would be built by lockdep though; that results in a false positive.

Thanks,
Yuyang