From patchwork Mon Mar 7 22:48:00 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 594160 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id B468F140BFB; Wed, 9 Mar 2016 00:05:22 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1adHKB-0005Xg-17; Tue, 08 Mar 2016 13:05:19 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1ad41P-0007rk-Ri for kernel-team@lists.ubuntu.com; Mon, 07 Mar 2016 22:53:03 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1ad41P-0000Dr-0U; Mon, 07 Mar 2016 22:53:03 +0000 Received: from kamal by fourier with local (Exim 4.86) (envelope-from ) id 1ad41M-0001wj-Ae; Mon, 07 Mar 2016 14:53:00 -0800 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 4.2.y-ckt 089/273] target: Fix LUN_RESET active TMR descriptor handling Date: Mon, 7 Mar 2016 14:48:00 -0800 Message-Id: <1457391064-6660-90-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1457391064-6660-1-git-send-email-kamal@canonical.com> References: <1457391064-6660-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 X-Mailman-Approved-At: Tue, 08 Mar 2016 13:05:01 +0000 Cc: Himanshu Madhani , Kamal Mostafa , Nicholas Bellinger , Sagi Grimberg , Mike Christie , Hannes Reinecke , Andy Grover , Christoph Hellwig X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 4.2.8-ckt5 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Nicholas Bellinger commit a6d9bb1c9605cd4f44e2d8290dc4d0e88f20292d upstream. This patch fixes a NULL pointer se_cmd->cmd_kref < 0 refcount bug during TMR LUN_RESET with active TMRs, triggered during se_cmd + se_tmr_req descriptor shutdown + release via core_tmr_drain_tmr_list(). To address this bug, go ahead and obtain a local kref_get_unless_zero(&se_cmd->cmd_kref) for active I/O to set CMD_T_ABORTED, and transport_wait_for_tasks() followed by the final target_put_sess_cmd() to drop the local ->cmd_kref. Also add two new checks within target_tmr_work() to avoid CMD_T_ABORTED -> TFO->queue_tm_rsp() callbacks ahead of invoking the backend -> fabric put in transport_cmd_check_stop_to_fabric(). For good measure, also change core_tmr_release_req() to use list_del_init() ahead of se_tmr_req memory free. Reviewed-by: Quinn Tran Cc: Himanshu Madhani Cc: Sagi Grimberg Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Andy Grover Cc: Mike Christie Signed-off-by: Nicholas Bellinger Signed-off-by: Kamal Mostafa --- drivers/target/target_core_tmr.c | 22 +++++++++++++++++++++- drivers/target/target_core_transport.c | 17 +++++++++++++++++ 2 files changed, 38 insertions(+), 1 deletion(-) diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c index 6545df43..3e3b12e 100644 --- a/drivers/target/target_core_tmr.c +++ b/drivers/target/target_core_tmr.c @@ -68,7 +68,7 @@ void core_tmr_release_req(struct se_tmr_req *tmr) if (dev) { spin_lock_irqsave(&dev->se_tmr_lock, flags); - list_del(&tmr->tmr_list); + list_del_init(&tmr->tmr_list); spin_unlock_irqrestore(&dev->se_tmr_lock, flags); } @@ -194,9 +194,11 @@ static void core_tmr_drain_tmr_list( struct list_head *preempt_and_abort_list) { LIST_HEAD(drain_tmr_list); + struct se_session *sess; struct se_tmr_req *tmr_p, *tmr_pp; struct se_cmd *cmd; unsigned long flags; + bool rc; /* * Release all pending and outgoing TMRs aside from the received * LUN_RESET tmr.. @@ -222,17 +224,31 @@ static void core_tmr_drain_tmr_list( if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd)) continue; + sess = cmd->se_sess; + if (WARN_ON_ONCE(!sess)) + continue; + + spin_lock(&sess->sess_cmd_lock); spin_lock(&cmd->t_state_lock); if (!(cmd->transport_state & CMD_T_ACTIVE)) { spin_unlock(&cmd->t_state_lock); + spin_unlock(&sess->sess_cmd_lock); continue; } if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) { spin_unlock(&cmd->t_state_lock); + spin_unlock(&sess->sess_cmd_lock); continue; } + cmd->transport_state |= CMD_T_ABORTED; spin_unlock(&cmd->t_state_lock); + rc = kref_get_unless_zero(&cmd->cmd_kref); + spin_unlock(&sess->sess_cmd_lock); + if (!rc) { + printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n"); + continue; + } list_move_tail(&tmr_p->tmr_list, &drain_tmr_list); } spin_unlock_irqrestore(&dev->se_tmr_lock, flags); @@ -246,7 +262,11 @@ static void core_tmr_drain_tmr_list( (preempt_and_abort_list) ? "Preempt" : "", tmr_p, tmr_p->function, tmr_p->response, cmd->t_state); + cancel_work_sync(&cmd->work); + transport_wait_for_tasks(cmd); + transport_cmd_finish_abort(cmd, 1); + target_put_sess_cmd(cmd); } } diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 9361567..2e89168 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -2954,8 +2954,17 @@ static void target_tmr_work(struct work_struct *work) struct se_cmd *cmd = container_of(work, struct se_cmd, work); struct se_device *dev = cmd->se_dev; struct se_tmr_req *tmr = cmd->se_tmr_req; + unsigned long flags; int ret; + spin_lock_irqsave(&cmd->t_state_lock, flags); + if (cmd->transport_state & CMD_T_ABORTED) { + tmr->response = TMR_FUNCTION_REJECTED; + spin_unlock_irqrestore(&cmd->t_state_lock, flags); + goto check_stop; + } + spin_unlock_irqrestore(&cmd->t_state_lock, flags); + switch (tmr->function) { case TMR_ABORT_TASK: core_tmr_abort_task(dev, tmr, cmd->se_sess); @@ -2988,9 +2997,17 @@ static void target_tmr_work(struct work_struct *work) break; } + spin_lock_irqsave(&cmd->t_state_lock, flags); + if (cmd->transport_state & CMD_T_ABORTED) { + spin_unlock_irqrestore(&cmd->t_state_lock, flags); + goto check_stop; + } cmd->t_state = TRANSPORT_ISTATE_PROCESSING; + spin_unlock_irqrestore(&cmd->t_state_lock, flags); + cmd->se_tfo->queue_tm_rsp(cmd); +check_stop: transport_cmd_check_stop_to_fabric(cmd); }