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 1889C1A01AF; Wed, 5 Jun 2024 12:02:46 +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=1717588967; cv=none; b=CRwAo5rlEZ3+HfJUz9n1E4pcyjuBtzUSdJD6mfVkJhxaEDlAxt91hBNp/NFxRziNuf/s2wb0+8ywqpaK+y4LCHEz0vbKOXmXm1dbQWT9zgfUQXe5W1GipqI4d44MOh3CstRJX1LBza9/MOBZlUr31hqXp9OGjGzIpc07V5tzIQ0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717588967; c=relaxed/simple; bh=60Kug0jDBKnuODkdJoUPwBKjkCCDWud9myyXf3mbQyQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nDi3MQSha3l1pG/2RpjjuOiLXESSb9xxSBjPKL1vKFDe6FKqkckOzSXDp9UJvJuJH7f0RY70GNGdigvEyu+ju/kk8DS4I/Ot0P9W8i1kAx+sjxiCyp18USeHc8jo0c5BQ6IqlUTkNJCUMSYkBRqlwzSb1WPlcZx51TMEIgKfHyE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gnbEImBR; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gnbEImBR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F3D3C4AF08; Wed, 5 Jun 2024 12:02:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1717588966; bh=60Kug0jDBKnuODkdJoUPwBKjkCCDWud9myyXf3mbQyQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gnbEImBRSUCsj6MrwTjt9Fm+eYapXuft/fjld0G4oAhCDMESF58JfNyrDbGbV2g/v FPWBj4me1ueMy4w02vAof2EsCiTQBpyE+cB+ySSXDNb6q3x4irJ++bRXPuzLicFnWt HWrQ+6Jeo4UWQJCi5C5c0astGqnu9eSh4md6scosM2e0aGLet048Ym62GCU8Gq8RXa SeIAM/C+cnVvaeA0YmBopUidKICL+qtRY8RCMsLY9FZ1g/6dyjUnINA99MybS3CdKl z/tbEOtSXp2mFCEDasmMWxpXvfGlM+TIPzZbsbRBazcgRmBfvyMf7+DouM0SxUuLtv rU2+Nx+wu4sog== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Sagi Grimberg , Alex Turin , Christoph Hellwig , Keith Busch , Sasha Levin , kch@nvidia.com, linux-nvme@lists.infradead.org Subject: [PATCH AUTOSEL 6.9 14/23] nvmet: fix a possible leak when destroy a ctrl during qp establishment Date: Wed, 5 Jun 2024 08:01:57 -0400 Message-ID: <20240605120220.2966127-14-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240605120220.2966127-1-sashal@kernel.org> References: <20240605120220.2966127-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.9.3 Content-Transfer-Encoding: 8bit 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 2fde22323622e..06f0c587f3437 100644 --- a/drivers/nvme/target/core.c +++ b/drivers/nvme/target/core.c @@ -818,6 +818,15 @@ 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