From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5FABC3A5A2 for ; Mon, 19 Aug 2019 15:02:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BAF0A206BB for ; Mon, 19 Aug 2019 15:02:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="IIWESImL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727341AbfHSPCs (ORCPT ); Mon, 19 Aug 2019 11:02:48 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:45252 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726343AbfHSPCr (ORCPT ); Mon, 19 Aug 2019 11:02:47 -0400 Received: by mail-pf1-f193.google.com with SMTP id w26so1311320pfq.12 for ; Mon, 19 Aug 2019 08:02:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=+9CFzHn8s+laxI8BbiaNVGIUIea83s76+v8r3smRCVQ=; b=IIWESImL05HMdmUWCk7CdXrrVK8p5KTTQdpU+vD0tyj6k4l5CVrh7/SOYo0/Nh+qgE fb/MR66i9vge+5vwNE6dzWU9Xw/R3JCtnaV+N351JYa8E6+N5+Zd+g7zhq/JYrpy+ZMM 29J2lx5q6HOXKXBvJVA+P3JdMJrF+Jw+NEhIA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=+9CFzHn8s+laxI8BbiaNVGIUIea83s76+v8r3smRCVQ=; b=CbHbc9+31eyjgf8oXHX37jAgmvzlr4H3BMhM2Au7a5M5CtmkOEj0jDvmg1WktyEGnX /b5lpAgK+H7yMgd4A3S2iWsGpVC2m2NNsnNlwogO/Rhy9KJC5ECsJHBFnnfLfnoLG4zQ oLn50tziEGuA2lttuqg2zni6WHoyo8QdMEea6vmfKhzHXQHI9NfVwfIkuTtjH38p4m6/ Y9qCSuv1b0N1B6AJbiwktnqn8+jBQKZa4N+EDY3Tk4eFtCRPwiKHgfGscVKVb+72xej8 pGeYUuHbBWbgq44l4GfDivOG3g3dRtc/iWiPiCsYzheCTeGRP7pEh/EzRI3YAZpzs8V6 Ec7A== X-Gm-Message-State: APjAAAVhh7qlNZrp5yV1f+vVEtSJKT8MbRE29DDGaDfue0Nm17FQV9Bt RQuJ/uwmjshqiNwp6Xl6ccVvNw== X-Google-Smtp-Source: APXvYqzs2lOTNxW35ufSm0/m7vXPfoTFMAUBPDgN2Ry7bYC+9vBffiCW4vSFFWlMZJF4Wsf0xiGRKw== X-Received: by 2002:a63:c03:: with SMTP id b3mr20765485pgl.23.1566226966877; Mon, 19 Aug 2019 08:02:46 -0700 (PDT) Received: from smtp.gmail.com ([2620:15c:202:1:fa53:7765:582b:82b9]) by smtp.gmail.com with ESMTPSA id w2sm22773353pjr.27.2019.08.19.08.02.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Aug 2019 08:02:46 -0700 (PDT) From: Stephen Boyd To: Herbert Xu Cc: linux-kernel@vger.kernel.org, "Theodore Ts'o" , linux-crypto@vger.kernel.org, Matt Mackall , Keerthy Subject: [PATCH] random: Support freezable kthreads in add_hwgenerator_randomness() Date: Mon, 19 Aug 2019 08:02:45 -0700 Message-Id: <20190819150245.176587-1-swboyd@chromium.org> X-Mailer: git-send-email 2.23.0.rc1.153.gdeed80330f-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The kthread calling this function is freezable after commit 03a3bb7ae631 ("hwrng: core - Freeze khwrng thread during suspend") is applied. Unfortunately, this function uses wait_event_interruptible() but doesn't check for the kthread being woken up by the fake freezer signal. When a user suspends the system, this kthread will wake up and if it fails the entropy size check it will immediately go back to sleep and not go into the freezer. Eventually, suspend will fail because the task never froze and a warning message like this may appear: PM: suspend entry (deep) Filesystems sync: 0.000 seconds Freezing user space processes ... (elapsed 0.001 seconds) done. OOM killer disabled. Freezing remaining freezable tasks ... Freezing of tasks failed after 20.003 seconds (1 tasks refusing to freeze, wq_busy=0): hwrng R running task 0 289 2 0x00000020 [] (__schedule) from [] (schedule+0x3c/0xc0) [] (schedule) from [] (add_hwgenerator_randomness+0xb0/0x100) [] (add_hwgenerator_randomness) from [] (hwrng_fillfn+0xc0/0x14c [rng_core]) [] (hwrng_fillfn [rng_core]) from [] (kthread+0x134/0x148) [] (kthread) from [] (ret_from_fork+0x14/0x2c) Check for a freezer signal here and skip adding any randomness if the task wakes up because it was frozen. This should make the kthread freeze properly and suspend work again. Fixes: 03a3bb7ae631 ("hwrng: core - Freeze khwrng thread during suspend") Reported-by: Keerthy Tested-by: Keerthy Signed-off-by: Stephen Boyd --- Probably needs to go via Herbert who routed the patch this is fixing. drivers/char/random.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index 5d5ea4ce1442..e2e85ca16410 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -2429,6 +2429,7 @@ void add_hwgenerator_randomness(const char *buffer, size_t count, size_t entropy) { struct entropy_store *poolp = &input_pool; + bool frozen = false; if (unlikely(crng_init == 0)) { crng_fast_load(buffer, count); @@ -2439,9 +2440,12 @@ void add_hwgenerator_randomness(const char *buffer, size_t count, * We'll be woken up again once below random_write_wakeup_thresh, * or when the calling thread is about to terminate. */ - wait_event_interruptible(random_write_wait, kthread_should_stop() || + wait_event_interruptible(random_write_wait, + kthread_freezable_should_stop(&frozen) || ENTROPY_BITS(&input_pool) <= random_write_wakeup_bits); - mix_pool_bytes(poolp, buffer, count); - credit_entropy_bits(poolp, entropy); + if (!frozen) { + mix_pool_bytes(poolp, buffer, count); + credit_entropy_bits(poolp, entropy); + } } EXPORT_SYMBOL_GPL(add_hwgenerator_randomness); -- Sent by a computer through tubes