[dpdk-dev] [PATCH v3 3/3] eal/linux: handle uio read failure in interrupt handler

Luca Boccassi bluca at debian.org
Wed Oct 31 19:39:45 CET 2018


If a device is unplugged while an interrupt is pending, the
read call to the uio device to remove it from the poll wait list
can fail resulting in it being continually polled forever. This
change checks for the read failing and if so, unregisters the device
as an interrupt source and causes the wait list to be rebuilt.

This race has been reported and observed in production.

Fixes: 0a45657a6794 ("pci: rework interrupt handling")
Cc: stable at dpdk.org

Signed-off-by: Brian Russell <brussell at brocade.com>
Signed-off-by: Luca Boccassi <bluca at debian.org>
---
 lib/librte_eal/linuxapp/eal/eal_interrupts.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_interrupts.c b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
index 39252a887..cbac451e1 100644
--- a/lib/librte_eal/linuxapp/eal/eal_interrupts.c
+++ b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
@@ -700,7 +700,7 @@ eal_intr_process_interrupts(struct epoll_event *events, int nfds)
 	bool call = false;
 	int n, bytes_read;
 	struct rte_intr_source *src;
-	struct rte_intr_callback *cb;
+	struct rte_intr_callback *cb, *next;
 	union rte_intr_read_buffer buf;
 	struct rte_intr_callback active_cb;
 
@@ -780,6 +780,23 @@ eal_intr_process_interrupts(struct epoll_event *events, int nfds)
 					"descriptor %d: %s\n",
 					events[n].data.fd,
 					strerror(errno));
+				/*
+				 * The device is unplugged or buggy, remove
+				 * it as an interrupt source and return to
+				 * force the wait list to be rebuilt.
+				 */
+				rte_spinlock_lock(&intr_lock);
+				TAILQ_REMOVE(&intr_sources, src, next);
+				rte_spinlock_unlock(&intr_lock);
+
+				for (cb = TAILQ_FIRST(&src->callbacks); cb;
+							cb = next) {
+					next = TAILQ_NEXT(cb, next);
+					TAILQ_REMOVE(&src->callbacks, cb, next);
+					free(cb);
+				}
+				free(src);
+				return -1;
 			} else if (bytes_read == 0)
 				RTE_LOG(ERR, EAL, "Read nothing from file "
 					"descriptor %d\n", events[n].data.fd);
-- 
2.19.1



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