From bcaee0d7f05a47979cff8e7ba7f6baebdf103e05 Mon Sep 17 00:00:00 2001 From: Christopher Faulet Date: Fri, 10 Oct 2025 14:32:04 +0200 Subject: [PATCH] BUG/MEDIUM: apppet: Improve spinning loop detection with the new API Conditions to detect the spinning loop for applets based on the new API are not accurrate. We cannot continue to check the channel's buffers state to know if an applet has made some progress. At least, we must also check the applet's buffers. After digging to find the right way to do, it was clear that the best is to use something similar to what is performed for the streams, namely, checking read and write events. And in fact, it is quite easy to do with the new API. So let's do so. This patch must be backported as far as 3.0. (cherry picked from commit 54b7539d64d70f033955a0bfe7d0f19d7eef2328) Signed-off-by: Willy Tarreau (cherry picked from commit 20623769917780b8fb7a01a7aa1a2539cc60961b) Signed-off-by: Willy Tarreau (cherry picked from commit ff753da75357e2595d69570b455f8c782297eb27) Signed-off-by: Willy Tarreau --- src/applet.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/src/applet.c b/src/applet.c index 2bc3eb5..9ab14bd 100644 --- a/src/applet.c +++ b/src/applet.c @@ -873,6 +873,7 @@ struct task *task_process_applet(struct task *t, void *context, unsigned int sta struct appctx *app = context; struct stconn *sc; unsigned int rate; + int did_send, did_recv; TRACE_ENTER(APPLET_EV_PROCESS, app); @@ -900,6 +901,7 @@ struct task *task_process_applet(struct task *t, void *context, unsigned int sta sc = appctx_sc(app); sc_applet_sync_send(sc); + did_send = (sc_oc(sc)->flags & CF_WRITE_EVENT); /* We always pretend the applet can't get and doesn't want to * put, it's up to it to change this if needed. This ensures @@ -916,7 +918,7 @@ struct task *task_process_applet(struct task *t, void *context, unsigned int sta applet_fl_test(app, APPCTX_FL_EOI|APPCTX_FL_EOS|APPCTX_FL_ERROR)) applet_have_more_data(app); - sc_applet_sync_recv(sc); + did_recv = sc_applet_sync_recv(sc); /* TODO: May be move in appctx_rcv_buf or sc_applet_process ? */ if (sc_waiting_room(sc) && (sc->flags & SC_FL_ABRT_DONE)) { @@ -924,11 +926,7 @@ struct task *task_process_applet(struct task *t, void *context, unsigned int sta } /* measure the call rate and check for anomalies when too high */ - if (((b_size(sc_ib(sc)) && sc->flags & SC_FL_NEED_BUFF) || // asks for a buffer which is present - (b_size(sc_ib(sc)) && !b_data(sc_ib(sc)) && sc->flags & SC_FL_NEED_ROOM) || // asks for room in an empty buffer - (b_data(sc_ob(sc)) && sc_is_send_allowed(sc)) || // asks for data already present - (!b_data(sc_ib(sc)) && b_data(sc_ob(sc)) && // didn't return anything ... - (!(sc_oc(sc)->flags & CF_WRITE_EVENT) && (sc->flags & SC_FL_SHUT_WANTED))))) { // ... and left data pending after a shut + if (!did_recv && !did_send) { rate = update_freq_ctr(&app->call_rate, 1); if (rate >= 100000 && app->call_rate.prev_ctr) // looped like this more than 100k times over last second stream_dump_and_crash(&app->obj_type, read_freq_ctr(&app->call_rate)); -- 1.7.10.4