[v2,3/3] eal/linux: handle uio read failure in interrupt handler
Checks
Commit Message
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@dpdk.org
Signed-off-by: Brian Russell <brussell@brocade.com>
Signed-off-by: Luca Boccassi <bluca@debian.org>
---
lib/librte_eal/linuxapp/eal/eal_interrupts.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
Comments
Looking for someone to review this patch please
19/09/2018 14:57, Luca Boccassi:
> 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@dpdk.org
>
> Signed-off-by: Brian Russell <brussell@brocade.com>
> Signed-off-by: Luca Boccassi <bluca@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 4076c6d6ca..34584db883 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_interrupts.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
> @@ -627,7 +627,7 @@ 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;
>
> @@ -701,6 +701,23 @@ 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);
>
@@ -627,7 +627,7 @@ 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;
@@ -701,6 +701,23 @@ 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);