@@ -233,8 +233,6 @@ static bool smc_llc_flow_start(struct smc_llc_flow *flow,
default:
flow->type = SMC_LLC_FLOW_NONE;
}
- if (qentry == lgr->delayed_event)
- lgr->delayed_event = NULL;
smc_llc_flow_qentry_set(flow, qentry);
spin_unlock_bh(&lgr->llc_flow_lock);
return true;
@@ -1603,13 +1601,12 @@ static void smc_llc_event_work(struct work_struct *work)
struct smc_llc_qentry *qentry;
if (!lgr->llc_flow_lcl.type && lgr->delayed_event) {
- if (smc_link_usable(lgr->delayed_event->link)) {
- smc_llc_event_handler(lgr->delayed_event);
- } else {
- qentry = lgr->delayed_event;
- lgr->delayed_event = NULL;
+ qentry = lgr->delayed_event;
+ lgr->delayed_event = NULL;
+ if (smc_link_usable(qentry->link))
+ smc_llc_event_handler(qentry);
+ else
kfree(qentry);
- }
}
again:
When a delayed event is enqueued then the event worker will send this event the next time it is running and no other flow is currently active. The event handler is called for the delayed event, and the pointer to the event keeps set in lgr->delayed_event. This pointer is cleared later in the processing by smc_llc_flow_start(). This can lead to a use-after-free condition when the processing does not reach smc_llc_flow_start(), but frees the event because of an error situation. Then the delayed_event pointer is still set but the event is freed. Fix this by always clearing the delayed event pointer when the event is provided to the event handler for processing, and remove the code to clear it in smc_llc_flow_start(). Fixes: 555da9af827d ("net/smc: add event-based llc_flow framework") Signed-off-by: Karsten Graul <kgraul@linux.ibm.com> --- net/smc/smc_llc.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-)