There is no change of behavior: for each kfunc, we store the prog sleepable state. But this allows to declare an async non sleepable callback from a syscall, where everything is sleepable.
Signed-off-by: Benjamin Tissoires bentiss@kernel.org
---
This is an RFC, and is not meant to be fully reviewed/applied as it is. I'm posting this to show what I wanted to explain in https://lore.kernel.org/bpf/mhkzkf4e23uvljtmwizwcxyuyat2tmfxn33xb4t7waafgmsa... --- kernel/bpf/verifier.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 5d42db05315e..856cb77d0f87 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5288,8 +5288,7 @@ static int map_kptr_match_type(struct bpf_verifier_env *env,
static bool in_sleepable(struct bpf_verifier_env *env) { - return env->prog->sleepable || - (env->cur_state && env->cur_state->in_sleepable); + return env->cur_state ? env->cur_state->in_sleepable : env->prog->sleepable; }
/* The non-sleepable programs and sleepable programs with explicit bpf_rcu_read_lock() @@ -20722,6 +20721,7 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog) state->curframe = 0; state->speculative = false; state->branches = 1; + state->in_sleepable = env->prog->sleepable; state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL); if (!state->frame[0]) { kfree(state);