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 693D52054F8; Thu, 12 Dec 2024 15:24:15 +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=1734017055; cv=none; b=tO3Lr4ZaDv8Sc7v46XSlmVzyR5wscDj0Dml2jr6NubY1XenWnviHkVTtZLEFTTBKkxA0Tygog3WcS8Ok73CwshLuVCtS5NaSs5PT1lOkcSB/mnC2KRo5MywZNFJW/bVIcqqcCgQuuU/n8YQtu2+R4/BS1oZzyYzgt0RPH26knNM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734017055; c=relaxed/simple; bh=5BKIWpM0xaJQnBbl76TTKNqQwRwuvK138vTt7iTsTHQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KQWc6SXryO2oQ8B5dZkP3ihyWV3xoE4wZ8J9ezhL98im6+5d5FSWJauSi5LYktKJLMfJ+MYLDzKb0/Jm4rO8Or4fcpQis9HqQ4Dz3EXagcTIioxVdHiI6RWGMZiHLTixGlgds7bQJA3dW8dZ2oh0y/i7aeSQNpf7v0Hp7MrASnw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=l7MpvXR+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="l7MpvXR+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF831C4CECE; Thu, 12 Dec 2024 15:24:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734017055; bh=5BKIWpM0xaJQnBbl76TTKNqQwRwuvK138vTt7iTsTHQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l7MpvXR+mJ0DQ9cfxHNyUIepsvU9OQhCNok3qaC9ol9lbH7qdhG/cd0kMRKQWk0kD t8vjsMlKeUgb4S9V1FTRK0CcuJp1e8yNRhORyFSVzHmkCYIs0k5KBA37wfIVpCL7U0 c4I9du/u95tLLxitDbSblGRfTcIccQiyLWIdImkw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Justin Tee , "Martin K. Petersen" , Sasha Levin Subject: [PATCH 6.12 370/466] scsi: lpfc: Prevent NDLP reference count underflow in dev_loss_tmo callback Date: Thu, 12 Dec 2024 15:58:59 +0100 Message-ID: <20241212144321.392625531@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241212144306.641051666@linuxfoundation.org> References: <20241212144306.641051666@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Justin Tee [ Upstream commit 4281f44ea8bfedd25938a0031bebba1473ece9ad ] Current dev_loss_tmo handling checks whether there has been a previous call to unregister with SCSI transport. If so, the NDLP kref count is decremented a second time in dev_loss_tmo as the final kref release. However, this can sometimes result in a reference count underflow if there is also a race to unregister with NVMe transport as well. Add a check for NVMe transport registration before decrementing the final kref. If NVMe transport is still registered, then the NVMe transport unregistration is designated as the final kref decrement. Signed-off-by: Justin Tee Link: https://lore.kernel.org/r/20241031223219.152342-8-justintee8345@gmail.com Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/scsi/lpfc/lpfc_hbadisc.c | 36 +++++++++++++++++++++----------- 1 file changed, 24 insertions(+), 12 deletions(-) diff --git a/drivers/scsi/lpfc/lpfc_hbadisc.c b/drivers/scsi/lpfc/lpfc_hbadisc.c index 9241075f72fa4..6e8d8a96c54fb 100644 --- a/drivers/scsi/lpfc/lpfc_hbadisc.c +++ b/drivers/scsi/lpfc/lpfc_hbadisc.c @@ -155,6 +155,7 @@ lpfc_dev_loss_tmo_callbk(struct fc_rport *rport) struct lpfc_hba *phba; struct lpfc_work_evt *evtp; unsigned long iflags; + bool nvme_reg = false; ndlp = ((struct lpfc_rport_data *)rport->dd_data)->pnode; if (!ndlp) @@ -177,38 +178,49 @@ lpfc_dev_loss_tmo_callbk(struct fc_rport *rport) /* Don't schedule a worker thread event if the vport is going down. */ if (test_bit(FC_UNLOADING, &vport->load_flag) || !test_bit(HBA_SETUP, &phba->hba_flag)) { + spin_lock_irqsave(&ndlp->lock, iflags); ndlp->rport = NULL; + if (ndlp->fc4_xpt_flags & NVME_XPT_REGD) + nvme_reg = true; + /* The scsi_transport is done with the rport so lpfc cannot - * call to unregister. Remove the scsi transport reference - * and clean up the SCSI transport node details. + * call to unregister. */ - if (ndlp->fc4_xpt_flags & (NLP_XPT_REGD | SCSI_XPT_REGD)) { + if (ndlp->fc4_xpt_flags & SCSI_XPT_REGD) { ndlp->fc4_xpt_flags &= ~SCSI_XPT_REGD; - /* NVME transport-registered rports need the - * NLP_XPT_REGD flag to complete an unregister. + /* If NLP_XPT_REGD was cleared in lpfc_nlp_unreg_node, + * unregister calls were made to the scsi and nvme + * transports and refcnt was already decremented. Clear + * the NLP_XPT_REGD flag only if the NVME Rport is + * confirmed unregistered. */ - if (!(ndlp->fc4_xpt_flags & NVME_XPT_REGD)) + if (!nvme_reg && ndlp->fc4_xpt_flags & NLP_XPT_REGD) { ndlp->fc4_xpt_flags &= ~NLP_XPT_REGD; + spin_unlock_irqrestore(&ndlp->lock, iflags); + lpfc_nlp_put(ndlp); /* may free ndlp */ + } else { + spin_unlock_irqrestore(&ndlp->lock, iflags); + } + } else { spin_unlock_irqrestore(&ndlp->lock, iflags); - lpfc_nlp_put(ndlp); - spin_lock_irqsave(&ndlp->lock, iflags); } + spin_lock_irqsave(&ndlp->lock, iflags); + /* Only 1 thread can drop the initial node reference. If * another thread has set NLP_DROPPED, this thread is done. */ - if (!(ndlp->fc4_xpt_flags & NVME_XPT_REGD) && - !(ndlp->nlp_flag & NLP_DROPPED)) { - ndlp->nlp_flag |= NLP_DROPPED; + if (nvme_reg || (ndlp->nlp_flag & NLP_DROPPED)) { spin_unlock_irqrestore(&ndlp->lock, iflags); - lpfc_nlp_put(ndlp); return; } + ndlp->nlp_flag |= NLP_DROPPED; spin_unlock_irqrestore(&ndlp->lock, iflags); + lpfc_nlp_put(ndlp); return; } -- 2.43.0