locking/local_lock: Introduce local_lock_irqsave_check()
Introduce local_lock_irqsave_check() to check that local_lock is
not taken recursively.
In !PREEMPT_RT local_lock_irqsave() disables IRQ, but
re-entrance is possible either from NMI or strategically placed
kprobe. The code should call local_lock_is_locked() before proceeding
to acquire a local_lock. Such local_lock_is_locked() might be called
earlier in the call graph and there could be a lot of code
between local_lock_is_locked() and local_lock_irqsave_check().
Without CONFIG_DEBUG_LOCK_ALLOC the local_lock_irqsave_check()
is equivalent to local_lock_irqsave().
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2 files changed
