From patchwork Thu Nov 17 18:36:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bart Van Assche X-Patchwork-Id: 13047194 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 809D5C433FE for ; Thu, 17 Nov 2022 18:36:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239518AbiKQSgg (ORCPT ); Thu, 17 Nov 2022 13:36:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40004 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234730AbiKQSgf (ORCPT ); Thu, 17 Nov 2022 13:36:35 -0500 Received: from mail-pf1-f175.google.com (mail-pf1-f175.google.com [209.85.210.175]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D4AA1F53 for ; Thu, 17 Nov 2022 10:36:34 -0800 (PST) Received: by mail-pf1-f175.google.com with SMTP id g62so2591664pfb.10 for ; Thu, 17 Nov 2022 10:36:34 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=mmXJwQRNVHGp1PPjICtnasAt06V6S6CeN/C6Fru7zmk=; b=Cxt++f6flQYblegJjK2p9YZdTjiSVHHRZCR1Kf1zyOStIqIZPSiOw/l6BFSvwnMl3Z 2ZGwHA/28k11LcKBp5USO0tYuv7Gs/h2mxoRNrqnO/OtOOnxMiF7Oin/ggVYGrNdeRs0 CuLQLIZb5Efc0EEsM6vKm79iDPXjIVpALr0lf7hv/Fj4GAolxX57KwguTyLo9sVg3SKB P7iA55bz9bSd1F9gaZDbxm9jTphTHatG5L3xT4ghelrldZtsf8l5Fh0/m9N61GeLAvlg x+N5uJBaM/0u3YKH19UPNigoQqZrPfvc3vP2j2M9R/RSmUR6QVw9PSdi0fC3N4BtZdx0 tpIQ== X-Gm-Message-State: ANoB5pn+1ZfusnSQvUtVTkFxLenWAwbxMXB/s8RBZxatr4IrkmDw+RoZ FW0lbpF/QHIMrFEfsmW7MRc= X-Google-Smtp-Source: AA0mqf5Y6qDU4h07fNXCzhK1/UObBYrui5k6lgO5Zfwg3ektsEZ4Z/nkl/M97a4szEHcoSF6P/GnYA== X-Received: by 2002:a63:f455:0:b0:476:e84b:ce4c with SMTP id p21-20020a63f455000000b00476e84bce4cmr3184357pgk.171.1668710194213; Thu, 17 Nov 2022 10:36:34 -0800 (PST) Received: from bvanassche-linux.mtv.corp.google.com ([2620:15c:211:201:7b21:f8f0:283b:9d21]) by smtp.gmail.com with ESMTPSA id z11-20020aa79e4b000000b0056c0d129edfsm1479073pfq.121.2022.11.17.10.36.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Nov 2022 10:36:33 -0800 (PST) From: Bart Van Assche To: "Martin K . Petersen" Cc: linux-scsi@vger.kernel.org, Bart Van Assche , Hannes Reinecke , Martin Wilck , Sachin Sant , Benjamin Block Subject: [PATCH 1/2] scsi: alua: Revert "Move a scsi_device_put() call out of alua_check_vpd()" Date: Thu, 17 Nov 2022 10:36:25 -0800 Message-Id: <20221117183626.2656196-2-bvanassche@acm.org> X-Mailer: git-send-email 2.38.1.584.g0f3c55d4c2-goog In-Reply-To: <20221117183626.2656196-1-bvanassche@acm.org> References: <20221117183626.2656196-1-bvanassche@acm.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org There is a bug in commit 0b25e17e9018 ("scsi: alua: Move a scsi_device_put() call out of alua_check_vpd()"): that patch may cause alua_rtpg_queue() callers to call scsi_device_put() even if that function should not be called. Revert that commit to prepare for a different solution. Cc: Hannes Reinecke Cc: Martin Wilck Cc: Sachin Sant Cc: Benjamin Block Reported-by: Sachin Sant Reported-by: Benjamin Block Signed-off-by: Bart Van Assche Tested-by: Sachin Sant > --- drivers/scsi/device_handler/scsi_dh_alua.c | 23 ++++++++-------------- 1 file changed, 8 insertions(+), 15 deletions(-) diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index 693cd827e138..bd4ee294f5c7 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -324,7 +324,6 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, struct alua_port_group *pg, *old_pg = NULL; bool pg_updated = false; unsigned long flags; - bool put_sdev; group_id = scsi_vpd_tpg_id(sdev, &rel_port); if (group_id < 0) { @@ -374,14 +373,11 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, list_add_rcu(&h->node, &pg->dh_list); spin_unlock_irqrestore(&pg->lock, flags); - put_sdev = alua_rtpg_queue(rcu_dereference_protected(h->pg, + alua_rtpg_queue(rcu_dereference_protected(h->pg, lockdep_is_held(&h->pg_lock)), sdev, NULL, true); spin_unlock(&h->pg_lock); - if (put_sdev) - scsi_device_put(sdev); - if (old_pg) kref_put(&old_pg->kref, release_port_group); @@ -982,10 +978,9 @@ static void alua_rtpg_work(struct work_struct *work) * RTPG already has been scheduled. * * Returns true if and only if alua_rtpg_work() will be called asynchronously. - * That function is responsible for calling @qdata->fn(). If this function - * returns true, the caller is responsible for invoking scsi_device_put(@sdev). + * That function is responsible for calling @qdata->fn(). */ -static bool __must_check alua_rtpg_queue(struct alua_port_group *pg, +static bool alua_rtpg_queue(struct alua_port_group *pg, struct scsi_device *sdev, struct alua_queue_data *qdata, bool force) { @@ -1024,6 +1019,8 @@ static bool __must_check alua_rtpg_queue(struct alua_port_group *pg, else kref_put(&pg->kref, release_port_group); } + if (sdev) + scsi_device_put(sdev); return true; } @@ -1130,12 +1127,10 @@ static int alua_activate(struct scsi_device *sdev, rcu_read_unlock(); mutex_unlock(&h->init_mutex); - if (alua_rtpg_queue(pg, sdev, qdata, true)) { - scsi_device_put(sdev); + if (alua_rtpg_queue(pg, sdev, qdata, true)) fn = NULL; - } else { + else err = SCSI_DH_DEV_OFFLINED; - } kref_put(&pg->kref, release_port_group); out: if (fn) @@ -1161,9 +1156,7 @@ static void alua_check(struct scsi_device *sdev, bool force) return; } rcu_read_unlock(); - - if (alua_rtpg_queue(pg, sdev, NULL, force)) - scsi_device_put(sdev); + alua_rtpg_queue(pg, sdev, NULL, force); kref_put(&pg->kref, release_port_group); } From patchwork Thu Nov 17 18:36:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bart Van Assche X-Patchwork-Id: 13047195 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6ED51C433FE for ; Thu, 17 Nov 2022 18:36:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240018AbiKQSgl (ORCPT ); Thu, 17 Nov 2022 13:36:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234984AbiKQSgh (ORCPT ); Thu, 17 Nov 2022 13:36:37 -0500 Received: from mail-pf1-f181.google.com (mail-pf1-f181.google.com [209.85.210.181]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C391B60C4 for ; Thu, 17 Nov 2022 10:36:36 -0800 (PST) Received: by mail-pf1-f181.google.com with SMTP id k22so2614265pfd.3 for ; Thu, 17 Nov 2022 10:36:36 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Uq8Yp6IG9XXMBmMEItW0bckONrZKpYGzu+wpVYzUfko=; b=lLqWtUYAePje57BqsudVwTxP1czLdnSSrUDmrimbwZHH529PBHf7mTfLHugL8Z0yWB Hg7ak/c747zeJcuJqnduqloJYYIZ9HGsq9Zx3hYV5OSLSpSzKYdTld9s0PDZtxDSW6I4 aHmAc9a6gNFlDVDGhk2B3+WTmO+7RYieCkliyQHInhX7LhOLsZRwS51ueFauZBk1u5TE N1xJwz1E+KbdGEBkHxSOr+wh+mlOVASaOJAABy/E1B41lecxRLictBiH3cCy9bU7ZhB/ FObHm2mxid9eE2fk+MTUa9tZDtZK08AxAOW7bdC6RIQzhlgyRrRom4uV8NmpO2YIyWe7 OCog== X-Gm-Message-State: ANoB5pn9HniysjDgTUU0r3fZUK97KIR/l8wAKeSHXOhkLS1R+ymwnPcd UHtZxYRZ8iMHSOccftvJr8s= X-Google-Smtp-Source: AA0mqf7vulMsIf1tpPHrBLcIIl15JyFJJTId44gV2gLb1Tlo1/cTzDAve5W+NCNbO5QIJnHptYj0ug== X-Received: by 2002:a63:ec03:0:b0:46e:e210:a491 with SMTP id j3-20020a63ec03000000b0046ee210a491mr3319569pgh.96.1668710196243; Thu, 17 Nov 2022 10:36:36 -0800 (PST) Received: from bvanassche-linux.mtv.corp.google.com ([2620:15c:211:201:7b21:f8f0:283b:9d21]) by smtp.gmail.com with ESMTPSA id z11-20020aa79e4b000000b0056c0d129edfsm1479073pfq.121.2022.11.17.10.36.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Nov 2022 10:36:35 -0800 (PST) From: Bart Van Assche To: "Martin K . Petersen" Cc: linux-scsi@vger.kernel.org, Bart Van Assche , Martin Wilck , Hannes Reinecke , Sachin Sant , Benjamin Block , Dan Carpenter Subject: [PATCH 2/2] scsi: alua: Call scsi_device_put() from non-atomic context Date: Thu, 17 Nov 2022 10:36:26 -0800 Message-Id: <20221117183626.2656196-3-bvanassche@acm.org> X-Mailer: git-send-email 2.38.1.584.g0f3c55d4c2-goog In-Reply-To: <20221117183626.2656196-1-bvanassche@acm.org> References: <20221117183626.2656196-1-bvanassche@acm.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Since commit f93ed747e2c7 ("scsi: core: Release SCSI devices synchronously"), scsi_device_put() might sleep. Avoid calling it from alua_rtpg_queue() with the pg_lock held. The lock only pretects h->pg, anyway. To avoid the pg being freed under us, because of a race with another thread, take a temporary reference. In alua_rtpg_queue(), verify that the pg still belongs to the sdev being passed before actually queueing the RTPG. This patch fixes the following smatch warning: drivers/scsi/device_handler/scsi_dh_alua.c:1013 alua_rtpg_queue() warn: sleeping in atomic context alua_check_vpd() <- disables preempt -> alua_rtpg_queue() -> scsi_device_put() Cc: Martin Wilck Cc: Hannes Reinecke Cc: Sachin Sant Cc: Benjamin Block Suggested-by: Martin Wilck Reported-by: Dan Carpenter Signed-off-by: Bart Van Assche --- drivers/scsi/device_handler/scsi_dh_alua.c | 27 +++++++++++++++------- 1 file changed, 19 insertions(+), 8 deletions(-) diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index bd4ee294f5c7..49cc18a87473 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -354,6 +354,8 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, "%s: port group %x rel port %x\n", ALUA_DH_NAME, group_id, rel_port); + kref_get(&pg->kref); + /* Check for existing port group references */ spin_lock(&h->pg_lock); old_pg = rcu_dereference_protected(h->pg, lockdep_is_held(&h->pg_lock)); @@ -373,11 +375,11 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, list_add_rcu(&h->node, &pg->dh_list); spin_unlock_irqrestore(&pg->lock, flags); - alua_rtpg_queue(rcu_dereference_protected(h->pg, - lockdep_is_held(&h->pg_lock)), - sdev, NULL, true); spin_unlock(&h->pg_lock); + alua_rtpg_queue(pg, sdev, NULL, true); + kref_put(&pg->kref, release_port_group); + if (old_pg) kref_put(&old_pg->kref, release_port_group); @@ -986,6 +988,9 @@ static bool alua_rtpg_queue(struct alua_port_group *pg, { int start_queue = 0; unsigned long flags; + + might_sleep(); + if (WARN_ON_ONCE(!pg) || scsi_device_get(sdev)) return false; @@ -996,11 +1001,17 @@ static bool alua_rtpg_queue(struct alua_port_group *pg, force = true; } if (pg->rtpg_sdev == NULL) { - pg->interval = 0; - pg->flags |= ALUA_PG_RUN_RTPG; - kref_get(&pg->kref); - pg->rtpg_sdev = sdev; - start_queue = 1; + struct alua_dh_data *h = sdev->handler_data; + + rcu_read_lock(); + if (h && rcu_dereference(h->pg) == pg) { + pg->interval = 0; + pg->flags |= ALUA_PG_RUN_RTPG; + kref_get(&pg->kref); + pg->rtpg_sdev = sdev; + start_queue = 1; + } + rcu_read_unlock(); } else if (!(pg->flags & ALUA_PG_RUN_RTPG) && force) { pg->flags |= ALUA_PG_RUN_RTPG; /* Do not queue if the worker is already running */