[PATCH] eal/linux: harden uevent recv error handling

[PATCH] eal/linux: harden uevent recv error handling

[Randy Tice]

The Linux uevent handler is harded for non-blocking receive behavior

Signed-off-by: Randy Tice <rtice@cisco.com>
---
 lib/eal/linux/eal_dev.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/eal/linux/eal_dev.c b/lib/eal/linux/eal_dev.c
index ec408649d0..29a889800a 100644
--- a/lib/eal/linux/eal_dev.c
+++ b/lib/eal/linux/eal_dev.c
@@ -241,9 +241,14 @@ dev_uev_handler(__rte_unused void *param)
 
 	ret = recv(rte_intr_fd_get(intr_handle), buf, EAL_UEV_MSG_LEN,
 		   MSG_DONTWAIT);
-	if (ret < 0 && errno == EAGAIN)
+	if (ret < 0 &&
+		(errno == EAGAIN || errno == EWOULDBLOCK))
 		return;
-	else if (ret <= 0) {
+	else if (ret < 0 &&
+		 (errno == ENOBUFS || errno == ENOMEM)) {
+		EAL_LOG(ERR, "unexpected error on uvent recv: %d", errno);
+		return;
+	} else if (ret <= 0) {
 		/* connection is closed or broken, can not up again. */
 		EAL_LOG(ERR, "uevent socket connection is broken.");
 		rte_eal_alarm_set(1, dev_delayed_unregister, NULL);
-- 
2.51.0

Re: [PATCH] eal/linux: harden uevent recv error handling

[Stephen Hemminger]

On Thu, 13 Aug 2026 16:16:56 -0400
Randy Tice <rtice@cisco.com> wrote:

> The Linux uevent handler is harded for non-blocking receive behavior
> 
> Signed-off-by: Randy Tice <rtice@cisco.com>
> ---

Good idea, but the code needs to unregister the uevent fd on error.
Also, fix spelling error, decode error message, and handle odd
case where recv() got interrupted.

Something like (untested):

diff --git a/lib/eal/linux/eal_dev.c b/lib/eal/linux/eal_dev.c
index ec408649d0..1985d5e122 100644
--- a/lib/eal/linux/eal_dev.c
+++ b/lib/eal/linux/eal_dev.c
@@ -241,11 +241,17 @@ dev_uev_handler(__rte_unused void *param)
 
 	ret = recv(rte_intr_fd_get(intr_handle), buf, EAL_UEV_MSG_LEN,
 		   MSG_DONTWAIT);
-	if (ret < 0 && errno == EAGAIN)
-		return;
-	else if (ret <= 0) {
-		/* connection is closed or broken, can not up again. */
-		EAL_LOG(ERR, "uevent socket connection is broken.");
+	if (ret <= 0) {
+		if (ret < 0) {
+			/* non blocking or interrupted */
+			if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
+				return;
+			EAL_ERR(ERR, "unexpected error on uevent: %s",
+				strerror(errno));
+		} else {
+			/* zero length recv is end of file */
+			EAL_LOG(ERR, "uevent socket connection is broken.");
+		}
 		rte_eal_alarm_set(1, dev_delayed_unregister, NULL);
 		return;
 	}