[dpdk-dev] [PATCH 0/1] Avoid race with unregister interrupt hanlder if interrupt

[dpdk-dev] [PATCH 0/1] Avoid race with unregister interrupt hanlder if interrupt

[Renata Saiakhova]

For pci_vfio, while removing the device by rte_dev_remove(),
pci_vfio_disable_notifier() will call rte_intr_callback_unregister(),
which may return -EAGAIN, if an interrupt source (kernel) has some active
callbacks right now. As a result, the callback (req notifier) can be never unregistered,
and the corresponding descriptor (vfio_req_intr_handle.fd) can be never closed.
The kernel will continuously try to notify the user space using req notifier, but as
the device is already removed, in this case it even cannot find a bus for that
device, the log is full of messages "EAL: Cannot find bus for device (XX:XX.X)"

Renata Saiakhova (1):
  librte_eal: wrapper around rte_intr_callback_unregister().

 lib/librte_eal/freebsd/eal_interrupts.c | 16 ++++++++++++++--
 lib/librte_eal/linux/eal_interrupts.c   | 16 ++++++++++++++--
 2 files changed, 28 insertions(+), 4 deletions(-)

-- 
2.17.2

[dpdk-dev] [PATCH 1/1] librte_eal: wrapper around rte_intr_callback_unregister().

[Renata Saiakhova]

Avoid race with unregister interrupt hanlder if interrupt
source has some active callbacks at the moment, use wrapper
around rte_intr_callback_unregister() to check for -EAGAIN
return value.

Signed-off-by: Renata Saiakhova <Renata.Saiakhova@ekinops.com>
---
 lib/librte_eal/freebsd/eal_interrupts.c | 16 ++++++++++++++--
 lib/librte_eal/linux/eal_interrupts.c   | 16 ++++++++++++++--
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eal/freebsd/eal_interrupts.c b/lib/librte_eal/freebsd/eal_interrupts.c
index 6d53d33c8..a92a7a025 100644
--- a/lib/librte_eal/freebsd/eal_interrupts.c
+++ b/lib/librte_eal/freebsd/eal_interrupts.c
@@ -259,8 +259,8 @@ rte_intr_callback_unregister_pending(const struct rte_intr_handle *intr_handle,
 	return ret;
 }
 
-int
-rte_intr_callback_unregister(const struct rte_intr_handle *intr_handle,
+static int
+__rte_intr_callback_unregister(const struct rte_intr_handle *intr_handle,
 		rte_intr_callback_fn cb_fn, void *cb_arg)
 {
 	int ret;
@@ -345,6 +345,18 @@ rte_intr_callback_unregister(const struct rte_intr_handle *intr_handle,
 	return ret;
 }
 
+int
+rte_intr_callback_unregister(const struct rte_intr_handle *intr_handle,
+		rte_intr_callback_fn cb_fn, void *cb_arg)
+{
+	int ret = 0;
+
+	while ((ret = __rte_intr_callback_unregister(intr_handle, cb_fn, cb_arg)) == -EAGAIN)
+		rte_pause();
+
+	return ret;
+}
+
 int
 rte_intr_enable(const struct rte_intr_handle *intr_handle)
 {
diff --git a/lib/librte_eal/linux/eal_interrupts.c b/lib/librte_eal/linux/eal_interrupts.c
index 13db5c4e8..d5dcfc36b 100644
--- a/lib/librte_eal/linux/eal_interrupts.c
+++ b/lib/librte_eal/linux/eal_interrupts.c
@@ -596,8 +596,8 @@ rte_intr_callback_unregister_pending(const struct rte_intr_handle *intr_handle,
 	return ret;
 }
 
-int
-rte_intr_callback_unregister(const struct rte_intr_handle *intr_handle,
+static int
+__rte_intr_callback_unregister(const struct rte_intr_handle *intr_handle,
 			rte_intr_callback_fn cb_fn, void *cb_arg)
 {
 	int ret;
@@ -662,6 +662,18 @@ rte_intr_callback_unregister(const struct rte_intr_handle *intr_handle,
 	return ret;
 }
 
+int
+rte_intr_callback_unregister(const struct rte_intr_handle *intr_handle,
+			rte_intr_callback_fn cb_fn, void *cb_arg)
+{
+	int ret = 0;
+
+	while ((ret = __rte_intr_callback_unregister(intr_handle, cb_fn, cb_arg)) == -EAGAIN)
+		rte_pause();
+
+	return ret;
+}
+
 int
 rte_intr_enable(const struct rte_intr_handle *intr_handle)
 {
-- 
2.17.2