From patchwork Thu Apr 7 06:37:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Duoming Zhou X-Patchwork-Id: 12804501 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 C5A1BC433F5 for ; Thu, 7 Apr 2022 06:39:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240591AbiDGGlA (ORCPT ); Thu, 7 Apr 2022 02:41:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49248 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241391AbiDGGkD (ORCPT ); Thu, 7 Apr 2022 02:40:03 -0400 Received: from zju.edu.cn (mail.zju.edu.cn [61.164.42.155]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 7C97D1F630; Wed, 6 Apr 2022 23:37:31 -0700 (PDT) Received: from ubuntu.localdomain (unknown [10.15.192.164]) by mail-app4 (Coremail) with SMTP id cS_KCgC3LqaYhk5i1Z7iAA--.43371S2; Thu, 07 Apr 2022 14:37:16 +0800 (CST) From: Duoming Zhou To: linux-kernel@vger.kernel.org Cc: chris@zankel.net, jcmvbkbc@gmail.com, mustafa.ismail@intel.com, shiraz.saleem@intel.com, jgg@ziepe.ca, wg@grandegger.com, mkl@pengutronix.de, davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, jes@trained-monkey.org, gregkh@linuxfoundation.org, jirislaby@kernel.org, alexander.deucher@amd.com, linux-xtensa@linux-xtensa.org, linux-rdma@vger.kernel.org, linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-hippi@sunsite.dk, linux-staging@lists.linux.dev, linux-serial@vger.kernel.org, linux-usb@vger.kernel.org, Duoming Zhou Subject: [PATCH 09/11] drivers: infiniband: hw: Fix deadlock in irdma_cleanup_cm_core() Date: Thu, 7 Apr 2022 14:37:12 +0800 Message-Id: <4069b99042d28c8e51b941d9e698b99d1656ed33.1649310812.git.duoming@zju.edu.cn> X-Mailer: git-send-email 2.17.1 In-Reply-To: References: X-CM-TRANSID: cS_KCgC3LqaYhk5i1Z7iAA--.43371S2 X-Coremail-Antispam: 1UD129KBjvJXoW7Aw13Ar15Xw1rZry3Gry7trb_yoW8Wr4fpr WDWryS9ryq9F42ka18Ww1DZFZrXw4kWFsFvryj9395ZF1rXFyUJF1fAr9IqFWDJF9Fgrs3 uF1YvryrCFZayr7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvG1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s1l1IIY67AE w4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2 IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW0oVCq3wA2z4x0Y4vEx4A2 jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS0I0E0xvYzxvE52 x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUAVWU twAv7VC2z280aVAFwI0_Gr0_Cr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI4 8JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwACI402YVCY1x02628vn2kIc2xKxwCF04k20xvY 0x0EwIxGrwCF04k20xvE74AGY7Cv6cx26r4fKr1UJr1l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr 1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE 14v26r4a6rW5MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_JFI_Gr1lIxAIcVC0I7 IYx2IY6xkF7I0E14v26r4UJVWxJr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvE x4A2jsIE14v26r4j6F4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr1j6F4UJbIYCTnIWIevJa 73UjIFyTuYvjfU5JPEDUUUU X-CM-SenderInfo: qssqjiasttq6lmxovvfxof0/1tbiAggNAVZdtZEcMgAJsO Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org There is a deadlock in irdma_cleanup_cm_core(), which is shown below: (Thread 1) | (Thread 2) | irdma_schedule_cm_timer() irdma_cleanup_cm_core() | add_timer() spin_lock_irqsave() //(1) | (wait a time) ... | irdma_cm_timer_tick() del_timer_sync() | spin_lock_irqsave() //(2) (wait timer to stop) | ... We hold cm_core->ht_lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need cm_core->ht_lock in position (2) of thread 2. As a result, irdma_cleanup_cm_core() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_irqsave(), which could let timer handler to obtain the needed lock. Signed-off-by: Duoming Zhou --- drivers/infiniband/hw/irdma/cm.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/hw/irdma/cm.c b/drivers/infiniband/hw/irdma/cm.c index dedb3b7edd8..019dd8bfe08 100644 --- a/drivers/infiniband/hw/irdma/cm.c +++ b/drivers/infiniband/hw/irdma/cm.c @@ -3252,8 +3252,11 @@ void irdma_cleanup_cm_core(struct irdma_cm_core *cm_core) return; spin_lock_irqsave(&cm_core->ht_lock, flags); - if (timer_pending(&cm_core->tcp_timer)) + if (timer_pending(&cm_core->tcp_timer)) { + spin_unlock_irqrestore(&cm_core->ht_lock, flags); del_timer_sync(&cm_core->tcp_timer); + spin_lock_irqsave(&cm_core->ht_lock, flags); + } spin_unlock_irqrestore(&cm_core->ht_lock, flags); destroy_workqueue(cm_core->event_wq);