patch 'ipc: avoid deadlock in async alarm callback' has been queued to stable release 25.11.3

[Kevin Traynor]

Hi,

FYI, your patch has been queued to stable release 25.11.3

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 08/01/26. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/kevintraynor/dpdk-stable

This queued commit can be viewed at:
https://github.com/kevintraynor/dpdk-stable/commit/b61122cf62633b8404ce3748dccb84ab1e14cf53

Thanks.

Kevin

---
>From b61122cf62633b8404ce3748dccb84ab1e14cf53 Mon Sep 17 00:00:00 2001
From: Anatoly Burakov <anatoly.burakov at intel.com>
Date: Fri, 26 Jun 2026 11:33:58 +0100
Subject: [PATCH] ipc: avoid deadlock in async alarm callback

[ upstream commit 9b0e79b868b35a62bcabe54c83faff88ed65e94d ]

async_reply_handle_thread_unsafe() can run while holding
pending_requests.lock and currently calls rte_eal_alarm_cancel().

rte_eal_alarm_cancel() may spin-wait for an executing callback, which can
deadlock if that callback is blocked on the same lock.

Remove callback-side alarm cancellation. It is safe to do so, because any
callback triggered without a pending request becomes a noop due to the
async request lookup now using numerical ID.

Fixes: daf9bfca717e ("ipc: remove thread for async requests")

Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>
---
 lib/eal/common/eal_common_proc.c | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/lib/eal/common/eal_common_proc.c b/lib/eal/common/eal_common_proc.c
index 0475aae1bf..514c928339 100644
--- a/lib/eal/common/eal_common_proc.c
+++ b/lib/eal/common/eal_common_proc.c
@@ -545,16 +545,4 @@ async_reply_handle_thread_unsafe(struct pending_request *req)
 	TAILQ_REMOVE(&pending_requests.requests, req, next);
 
-	if (rte_eal_alarm_cancel(async_reply_handle, (void *)(uintptr_t)req->id) < 0) {
-		/* if we failed to cancel the alarm because it's already in
-		 * progress, don't proceed because otherwise we will end up
-		 * handling the same message twice.
-		 */
-		if (rte_errno == EINPROGRESS) {
-			EAL_LOG(DEBUG, "Request handling is already in progress");
-			goto no_trigger;
-		}
-		EAL_LOG(ERR, "Failed to cancel alarm");
-	}
-
 	if (action == ACTION_TRIGGER)
 		return req;
-- 
2.55.0

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2026-07-28 16:54:53.012043017 +0100
+++ 0076-ipc-avoid-deadlock-in-async-alarm-callback.patch	2026-07-28 16:54:50.833803911 +0100
@@ -1 +1 @@
-From 9b0e79b868b35a62bcabe54c83faff88ed65e94d Mon Sep 17 00:00:00 2001
+From b61122cf62633b8404ce3748dccb84ab1e14cf53 Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit 9b0e79b868b35a62bcabe54c83faff88ed65e94d ]
+
@@ -17 +18,0 @@
-Cc: stable at dpdk.org
@@ -25 +26 @@
-index 31eebae204..b73e390e48 100644
+index 0475aae1bf..514c928339 100644
@@ -28 +29 @@
-@@ -549,16 +549,4 @@ async_reply_handle_thread_unsafe(struct pending_request *req)
+@@ -545,16 +545,4 @@ async_reply_handle_thread_unsafe(struct pending_request *req)