From 415433ae3b66ec27faae9f2e956159f814f639c4 Mon Sep 17 00:00:00 2001 From: kan Date: Mon, 20 Aug 2012 15:19:34 +0000 Subject: [PATCH] MFC r239095: Do not add handler to event handlers list until ithread is created. In rare event when fast and ithread interrupts share the same vector and the fast handler was registered first, we can end up trying to schedule the ithread that is not created yet. The kernel built with INVARIANTS then triggers an assertion. Change the order to create the ithread first and only then add the handler that needs it to the interrupt event handlers list. Approved by: re (kib) Reviewed by: jhb git-svn-id: svn://svn.freebsd.org/base/releng/9.1@239437 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f --- sys/kern/kern_intr.c | 52 +++++++++++++++++++++++--------------------- 1 file changed, 27 insertions(+), 25 deletions(-) diff --git a/sys/kern/kern_intr.c b/sys/kern/kern_intr.c index 08ff34b1..c3d8fcb1 100644 --- a/sys/kern/kern_intr.c +++ b/sys/kern/kern_intr.c @@ -545,17 +545,6 @@ intr_event_add_handler(struct intr_event *ie, const char *name, } } - /* Add the new handler to the event in priority order. */ - TAILQ_FOREACH(temp_ih, &ie->ie_handlers, ih_next) { - if (temp_ih->ih_pri > ih->ih_pri) - break; - } - if (temp_ih == NULL) - TAILQ_INSERT_TAIL(&ie->ie_handlers, ih, ih_next); - else - TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next); - intr_event_update(ie); - /* Create a thread if we need one. */ while (ie->ie_thread == NULL && handler != NULL) { if (ie->ie_flags & IE_ADDING_THREAD) @@ -572,6 +561,18 @@ intr_event_add_handler(struct intr_event *ie, const char *name, wakeup(ie); } } + + /* Add the new handler to the event in priority order. */ + TAILQ_FOREACH(temp_ih, &ie->ie_handlers, ih_next) { + if (temp_ih->ih_pri > ih->ih_pri) + break; + } + if (temp_ih == NULL) + TAILQ_INSERT_TAIL(&ie->ie_handlers, ih, ih_next); + else + TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next); + intr_event_update(ie); + CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name, ie->ie_name); mtx_unlock(&ie->ie_lock); @@ -618,23 +619,12 @@ intr_event_add_handler(struct intr_event *ie, const char *name, } } - /* Add the new handler to the event in priority order. */ - TAILQ_FOREACH(temp_ih, &ie->ie_handlers, ih_next) { - if (temp_ih->ih_pri > ih->ih_pri) - break; - } - if (temp_ih == NULL) - TAILQ_INSERT_TAIL(&ie->ie_handlers, ih, ih_next); - else - TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next); - intr_event_update(ie); - /* For filtered handlers, create a private ithread to run on. */ - if (filter != NULL && handler != NULL) { + if (filter != NULL && handler != NULL) { mtx_unlock(&ie->ie_lock); - it = ithread_create("intr: newborn", ih); + it = ithread_create("intr: newborn", ih); mtx_lock(&ie->ie_lock); - it->it_event = ie; + it->it_event = ie; ih->ih_thread = it; ithread_update(it); // XXX - do we really need this?!?!? } else { /* Create the global per-event thread if we need one. */ @@ -654,6 +644,18 @@ intr_event_add_handler(struct intr_event *ie, const char *name, } } } + + /* Add the new handler to the event in priority order. */ + TAILQ_FOREACH(temp_ih, &ie->ie_handlers, ih_next) { + if (temp_ih->ih_pri > ih->ih_pri) + break; + } + if (temp_ih == NULL) + TAILQ_INSERT_TAIL(&ie->ie_handlers, ih, ih_next); + else + TAILQ_INSERT_BEFORE(temp_ih, ih, ih_next); + intr_event_update(ie); + CTR3(KTR_INTR, "%s: added %s to %s", __func__, ih->ih_name, ie->ie_name); mtx_unlock(&ie->ie_lock); -- 2.42.0