linux-kernel - [PATCH AUTOSEL 4.19 04/59] nvme: fix possible deadlock when nvme_update

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Date:   Sat, 26 Oct 2019 09:18:15 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Sagi Grimberg <sagi@...mberg.me>,
        Judy Brock <judy.brock@...sung.com>,
        Sasha Levin <sashal@...nel.org>, linux-nvme@...ts.infradead.org
Subject: [PATCH AUTOSEL 4.19 04/59] nvme: fix possible deadlock when nvme_update_formats fails

From: Sagi Grimberg <sagi@...mberg.me>

[ Upstream commit 6abff1b9f7b8884a46b7bd80b49e7af0b5625aeb ]

nvme_update_formats may fail to revalidate the namespace and
attempt to remove the namespace. This may lead to a deadlock
as nvme_ns_remove will attempt to acquire the subsystem lock
which is already acquired by the passthru command with effects.

Move the invalid namepsace removal to after the passthru command
releases the subsystem lock.

Reported-by: Judy Brock <judy.brock@...sung.com>
Signed-off-by: Sagi Grimberg <sagi@...mberg.me>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/nvme/host/core.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index ae0b01059fc6d..ddd5c72a565ad 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1201,8 +1201,6 @@ static void nvme_update_formats(struct nvme_ctrl *ctrl)
 		if (ns->disk && nvme_revalidate_disk(ns->disk))
 			nvme_set_queue_dying(ns);
 	up_read(&ctrl->namespaces_rwsem);
-
-	nvme_remove_invalid_namespaces(ctrl, NVME_NSID_ALL);
 }
 
 static void nvme_passthru_end(struct nvme_ctrl *ctrl, u32 effects)
@@ -1218,6 +1216,7 @@ static void nvme_passthru_end(struct nvme_ctrl *ctrl, u32 effects)
 		nvme_unfreeze(ctrl);
 		nvme_mpath_unfreeze(ctrl->subsys);
 		mutex_unlock(&ctrl->subsys->lock);
+		nvme_remove_invalid_namespaces(ctrl, NVME_NSID_ALL);
 		mutex_unlock(&ctrl->scan_lock);
 	}
 	if (effects & NVME_CMD_EFFECTS_CCC)
-- 
2.20.1