From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BA55355E4C; Tue, 9 Jul 2024 11:17:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720523862; cv=none; b=uLg0eOm1q5CS0JUvb6gE/G6YiM7uRkoG/MSpvsz7N5lfcdGHCXctB6G5JwlGUwBbsD1wu+vtKQ/eCLj8n1h0dF7YHtNaUyFlrBQsVjyVYGUx4gIBdHIHrCWXoYHOygrwwhzWKr+EGRzxVcc94n0kO1ShacHZCfc9itYw2UcV1rM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720523862; c=relaxed/simple; bh=QbeFhw/ODNT6G6Zq/Bsq37m2o8/yRq9AfWHHWReUPQk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qhN41KhBNvQukzSQJNrvK3S5Na5uKuFCp4Aqxbo7Gan3JqHmi8PLalyagY7AEpyRycaN0byT6ywZlwWHIKhn3gBpRoqertdPofbDilg4uFWiKbosJAzQJavUrflaM/+LjyHuuO7rOvtpYu2yIHSwaHrOho1CjUdSonlfIALxnZA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mmZrZKEP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mmZrZKEP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3EE85C3277B; Tue, 9 Jul 2024 11:17:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1720523862; bh=QbeFhw/ODNT6G6Zq/Bsq37m2o8/yRq9AfWHHWReUPQk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mmZrZKEPTboLkGMxSXWnj3Q/Xsz1AtzS8Npgs/FakhBAerftyDPOVIfp5D4ayRz5I 31R2I0YYLE5ik/x05SMp3Iet/Xz8OW0I5lkqBFAGX3VtUsul3M/pb6Qp29QhXalJq1 VKFyKB0d90AwZcQjPLDFXUibp9Sz2Ec7hGxyHB6U= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alex Turin , Sagi Grimberg , Christoph Hellwig , Keith Busch , Sasha Levin Subject: [PATCH 6.6 132/139] nvmet: fix a possible leak when destroy a ctrl during qp establishment Date: Tue, 9 Jul 2024 13:10:32 +0200 Message-ID: <20240709110703.267986423@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240709110658.146853929@linuxfoundation.org> References: <20240709110658.146853929@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sagi Grimberg [ Upstream commit c758b77d4a0a0ed3a1292b3fd7a2aeccd1a169a4 ] In nvmet_sq_destroy we capture sq->ctrl early and if it is non-NULL we know that a ctrl was allocated (in the admin connect request handler) and we need to release pending AERs, clear ctrl->sqs and sq->ctrl (for nvme-loop primarily), and drop the final reference on the ctrl. However, a small window is possible where nvmet_sq_destroy starts (as a result of the client giving up and disconnecting) concurrently with the nvme admin connect cmd (which may be in an early stage). But *before* kill_and_confirm of sq->ref (i.e. the admin connect managed to get an sq live reference). In this case, sq->ctrl was allocated however after it was captured in a local variable in nvmet_sq_destroy. This prevented the final reference drop on the ctrl. Solve this by re-capturing the sq->ctrl after all inflight request has completed, where for sure sq->ctrl reference is final, and move forward based on that. This issue was observed in an environment with many hosts connecting multiple ctrls simoutanuosly, creating a delay in allocating a ctrl leading up to this race window. Reported-by: Alex Turin Signed-off-by: Sagi Grimberg Reviewed-by: Christoph Hellwig Signed-off-by: Keith Busch Signed-off-by: Sasha Levin --- drivers/nvme/target/core.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c index ce7e945cb4f7e..cfba3ec7add84 100644 --- a/drivers/nvme/target/core.c +++ b/drivers/nvme/target/core.c @@ -806,6 +806,15 @@ void nvmet_sq_destroy(struct nvmet_sq *sq) percpu_ref_exit(&sq->ref); nvmet_auth_sq_free(sq); + /* + * we must reference the ctrl again after waiting for inflight IO + * to complete. Because admin connect may have sneaked in after we + * store sq->ctrl locally, but before we killed the percpu_ref. the + * admin connect allocates and assigns sq->ctrl, which now needs a + * final ref put, as this ctrl is going away. + */ + ctrl = sq->ctrl; + if (ctrl) { /* * The teardown flow may take some time, and the host may not -- 2.43.0