tree 4157ac7296cd23beaad7795af7116eb1cfd14856
parent aa2e999037be47f557890eb93856b85f122bd67e
author Alexei Starovoitov <ast@kernel.org> 1746063812 -0700
committer Alexei Starovoitov <ast@kernel.org> 1746068951 -0700

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>