On 2024-10-25 15:08, Jordan Rife wrote:
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 59de664e580d..1191dc1d4206 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3006,14 +3006,21 @@ static void bpf_link_free(struct bpf_link *link) bpf_prog_put(link->prog);I think we would need the same treatment with bpf_prog_put here. Something like, tracepoint_call_rcu(raw_tp->btp->tp, &link->prog->aux->rcu, bpf_link_defer_bpf_prog_put); static void bpf_link_defer_bpf_prog_put(struct rcu_head *rcu) { struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu); bpf_prog_put(aux->prox); }
Sure, I'll add this in a v2.
Alternatively, some context would need to be passed down to __bpf_prog_put_noref via the call to bpf_prog_put so it can choose whether or not to use call_rcu or call_rcu_tasks_trace.
Also possible, but more cumbersome.
-static inline void release_probes(struct tracepoint_func *old) +static bool tracepoint_is_syscall(struct tracepoint *tp) +{ + return !strcmp(tp->name, "sys_enter") || !strcmp(tp->name, "sys_exit"); +}I'm curious if it might be better to add some field to struct tracepoint like "sleepable" rather than adding a special case here based on the name? Of course, if it's only ever going to be these two cases then maybe adding a new field doesn't make sense.
I know Steven is reluctant to bloat the tracepoint struct because there are lots of tracepoint instances (thousands). So for now I thought that just comparing the name would be a good start. We can eventually go a different route as well: introduce a section just to put the syscall tracepoints, and compare the struct tracepoint pointers to the section begin/end range. But it's rather complex for what should remain a simple fix. Thanks, Mathieu
-Jordan
-- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com
