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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Alexander Lobakin <alexandr.lobakin@intel.com>,
        Michal Kubiak <michal.kubiak@intel.com>,
        Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
        Tony Nguyen <anthony.l.nguyen@intel.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0638/1017] ice: dont allow to run ice_send_event_to_aux() in atomic ctx
Date:   Tue,  5 Apr 2022 09:25:51 +0200
Message-Id: <20220405070413.221449890@linuxfoundation.org>
In-Reply-To: <20220405070354.155796697@linuxfoundation.org>
References: <20220405070354.155796697@linuxfoundation.org>
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From: Alexander Lobakin <alexandr.lobakin@intel.com>

[ Upstream commit 5a3156932da06f09953764de113419f254086faf ]

ice_send_event_to_aux() eventually descends to mutex_lock()
(-> might_sched()), so it must not be called under non-task
context. However, at least two fixes have happened already for the
bug splats occurred due to this function being called from atomic
context.
To make the emergency landings softer, bail out early when executed
in non-task context emitting a warn splat only once. This way we
trade some events being potentially lost for system stability and
avoid any related hangs and crashes.

Fixes: 348048e724a0e ("ice: Implement iidc operations")
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Tested-by: Michal Kubiak <michal.kubiak@intel.com>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Acked-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/intel/ice/ice_idc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/intel/ice/ice_idc.c b/drivers/net/ethernet/intel/ice/ice_idc.c
index adcc9a251595..a2714988dd96 100644
--- a/drivers/net/ethernet/intel/ice/ice_idc.c
+++ b/drivers/net/ethernet/intel/ice/ice_idc.c
@@ -34,6 +34,9 @@ void ice_send_event_to_aux(struct ice_pf *pf, struct iidc_event *event)
 {
 	struct iidc_auxiliary_drv *iadrv;
 
+	if (WARN_ON_ONCE(!in_task()))
+		return;
+
 	if (!pf->adev)
 		return;
 
-- 
2.34.1