From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Long Li <longli@microsoft.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.18 0886/1250] net: mana: Clear RDMA teardown and suspend state in mana_rdma_probe()
Date: Thu, 17 Sep 2026 16:11:21 +0100
Message-ID: <20260917151615.997595207@linuxfoundation.org>
In-Reply-To: <20260917151551.901433442@linuxfoundation.org>
References: <20260917151551.901433442@linuxfoundation.org>
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6.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Long Li <longli@microsoft.com>

[ Upstream commit f6d61fe4c19cf448e5cba6d8767b4e6966f58606 ]

mana_rdma_remove() sets gd->rdma_teardown to stop
mana_rdma_service_handle() from acting on servicing events, but nothing
ever clears it. A hardware service reset (GDMA_EQE_HWC_RESET_REQUEST)
goes through mana_gd_suspend() -> mana_rdma_remove() and mana_gd_resume()
-> mana_rdma_probe(), so from the first reset onwards every
GDMA_EQE_HWC_SOC_SERVICE event returns early and RDMA suspend/resume
servicing is silently dropped for the life of the device.

gd->is_suspended has the same problem: it is set when servicing removes
the adev and is cleared only by a matching resume. A reset while RDMA is
suspended re-adds the adev but leaves is_suspended set, so a later resume
event calls add_adev() on top of a live gd->adev and leaks it. This is
currently masked by the rdma_teardown bug.

Clear both in mana_rdma_probe(). On the reset path mana_rdma_remove()
has closed the gate and drained the service workqueue, so clear
is_suspended first and re-open the gate with smp_store_release(), paired
with smp_load_acquire() in the handler, so the handler cannot observe an
open gate with a stale is_suspended. On the initial probe path the gate
was never closed and both flags are already clear.

This does not order gd->adev, which add_adev() publishes afterwards. A
servicing event arriving in that window is still dropped, as it is in
mainline today on the initial probe path; closing it needs probe and the
handler to be serialized and is left to a separate change.

Fixes: 505cc26bcae0 ("net: mana: Add support for auxiliary device servicing events")
Signed-off-by: Long Li <longli@microsoft.com>
Link: https://patch.msgid.link/20260902175153.3410560-1-longli@microsoft.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/microsoft/mana/mana_en.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index b61da240ac1bb..a7c1b965c0e95 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -3541,7 +3541,8 @@ static void mana_rdma_service_handle(struct work_struct *work)
 	struct device *dev = gd->gdma_context->dev;
 	int ret;
 
-	if (READ_ONCE(gd->rdma_teardown))
+	/* Pairs with the smp_store_release() in mana_rdma_probe(). */
+	if (smp_load_acquire(&gd->rdma_teardown))
 		goto out;
 
 	switch (serv_work->event) {
@@ -3823,6 +3824,21 @@ int mana_rdma_probe(struct gdma_dev *gd)
 	if (err)
 		return err;
 
+	/* Clear the state left by a previous mana_rdma_remove() so servicing
+	 * events are handled again after a reset cycle.
+	 */
+	gd->is_suspended = false;
+
+	/* Publish is_suspended before re-opening the gate, so the handler
+	 * cannot observe an open gate with a stale is_suspended.  Pairs
+	 * with the smp_load_acquire() in mana_rdma_service_handle().  This
+	 * matters on the reset path, where mana_rdma_remove() closed the
+	 * gate and drained the workqueue; on the initial probe path the
+	 * gate was never closed and both flags are already clear.  It does
+	 * not order gd->adev, which add_adev() publishes below.
+	 */
+	smp_store_release(&gd->rdma_teardown, false);
+
 	err = add_adev(gd, "rdma");
 	if (err)
 		mana_gd_deregister_device(gd);
-- 
2.53.0