Commit e25ddfb3 authored by Leon Hwang's avatar Leon Hwang Committed by Alexei Starovoitov
Browse files

bpf: Reject bpf_timer for PREEMPT_RT 



When enable CONFIG_PREEMPT_RT, the kernel will warn when run timer
selftests by './test_progs -t timer':

BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48

In order to avoid such warning, reject bpf_timer in verifier when
PREEMPT_RT is enabled.

Signed-off-by: default avatarLeon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20250910125740.52172-2-leon.hwang@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent a3967baa

kernel/bpf/verifier.c

+4 −0
Original line number Diff line number Diff line
@@ -8547,6 +8547,10 @@ static int process_timer_func(struct bpf_verifier_env *env, int regno, 
		verifier_bug(env, "Two map pointers in a timer helper");

		return -EFAULT;

	}

	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {

		verbose(env, "bpf_timer cannot be used for PREEMPT_RT.\n");

		return -EOPNOTSUPP;

	}

	meta->map_uid = reg->map_uid;

	meta->map_ptr = map;

	return 0;