kernel/events/core.c: perf_event_set_filter: cannot annotate due to aliasing

[bulwahn]

kernel/events/core.c:9392:3: warning: releasing mutex 'ctx->mutex' that was not held [-Wthread-safety-analysis]
                mutex_unlock(&ctx->mutex);
                ^
kernel/events/core.c:9400:2: warning: mutex 'ctx->mutex' is not held on every path through here [-Wthread-safety-analysis]
        kfree(filter_str);
        ^
kernel/events/core.c:9394:3: note: mutex acquired here
                mutex_lock(&ctx->mutex);
                ^

We cannot annotate __requires on this mutex, as ctx is a local variable (an aliasing issue).