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 9FD4415AE7 for ; Wed, 20 Sep 2023 12:15:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1FA18C433C7; Wed, 20 Sep 2023 12:15:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1695212117; bh=a8PrbD/8g6magA2g4j87+r5VsOI/AxDNrxZyn8TQy9g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=clptlTnx/dCwey3Z920WETD4kUAVR2aKKiMwQi29CbOuxfrSw416I5clE2hLhP2Nt fflKFWQWp7/9ckFAX1aHfzs28yxNdGhCjQ/K5ovrzv2GruYMPQR5T9uL4Q0zKHhCgF 9f5BjuNw+7Hb+6jmhQgUVNeqkD5DdZzw6PHwQSNY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chengfeng Ye , Davidlohr Bueso , "Martin K. Petersen" , Sasha Levin Subject: [PATCH 4.19 156/273] scsi: fcoe: Fix potential deadlock on &fip->ctlr_lock Date: Wed, 20 Sep 2023 13:29:56 +0200 Message-ID: <20230920112851.352484070@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230920112846.440597133@linuxfoundation.org> References: <20230920112846.440597133@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chengfeng Ye [ Upstream commit 1a1975551943f681772720f639ff42fbaa746212 ] There is a long call chain that &fip->ctlr_lock is acquired by isr fnic_isr_msix_wq_copy() under hard IRQ context. Thus other process context code acquiring the lock should disable IRQ, otherwise deadlock could happen if the IRQ preempts the execution while the lock is held in process context on the same CPU. [ISR] fnic_isr_msix_wq_copy() -> fnic_wq_copy_cmpl_handler() -> fnic_fcpio_cmpl_handler() -> fnic_fcpio_flogi_reg_cmpl_handler() -> fnic_flush_tx() -> fnic_send_frame() -> fcoe_ctlr_els_send() -> spin_lock_bh(&fip->ctlr_lock) [Process Context] 1. fcoe_ctlr_timer_work() -> fcoe_ctlr_flogi_send() -> spin_lock_bh(&fip->ctlr_lock) 2. fcoe_ctlr_recv_work() -> fcoe_ctlr_recv_handler() -> fcoe_ctlr_recv_els() -> fcoe_ctlr_announce() -> spin_lock_bh(&fip->ctlr_lock) 3. fcoe_ctlr_recv_work() -> fcoe_ctlr_recv_handler() -> fcoe_ctlr_recv_els() -> fcoe_ctlr_flogi_retry() -> spin_lock_bh(&fip->ctlr_lock) 4. -> fcoe_xmit() -> fcoe_ctlr_els_send() -> spin_lock_bh(&fip->ctlr_lock) spin_lock_bh() is not enough since fnic_isr_msix_wq_copy() is a hardirq. These flaws were found by an experimental static analysis tool I am developing for irq-related deadlock. The patch fix the potential deadlocks by spin_lock_irqsave() to disable hard irq. Fixes: 794d98e77f59 ("[SCSI] libfcoe: retry rejected FLOGI to another FCF if possible") Signed-off-by: Chengfeng Ye Link: https://lore.kernel.org/r/20230817074708.7509-1-dg573847474@gmail.com Reviewed-by: Davidlohr Bueso Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/scsi/fcoe/fcoe_ctlr.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/scsi/fcoe/fcoe_ctlr.c b/drivers/scsi/fcoe/fcoe_ctlr.c index 1e087a206f48e..c49986eba47b6 100644 --- a/drivers/scsi/fcoe/fcoe_ctlr.c +++ b/drivers/scsi/fcoe/fcoe_ctlr.c @@ -330,16 +330,17 @@ static void fcoe_ctlr_announce(struct fcoe_ctlr *fip) { struct fcoe_fcf *sel; struct fcoe_fcf *fcf; + unsigned long flags; mutex_lock(&fip->ctlr_mutex); - spin_lock_bh(&fip->ctlr_lock); + spin_lock_irqsave(&fip->ctlr_lock, flags); kfree_skb(fip->flogi_req); fip->flogi_req = NULL; list_for_each_entry(fcf, &fip->fcfs, list) fcf->flogi_sent = 0; - spin_unlock_bh(&fip->ctlr_lock); + spin_unlock_irqrestore(&fip->ctlr_lock, flags); sel = fip->sel_fcf; if (sel && ether_addr_equal(sel->fcf_mac, fip->dest_addr)) @@ -709,6 +710,7 @@ int fcoe_ctlr_els_send(struct fcoe_ctlr *fip, struct fc_lport *lport, { struct fc_frame *fp; struct fc_frame_header *fh; + unsigned long flags; u16 old_xid; u8 op; u8 mac[ETH_ALEN]; @@ -742,11 +744,11 @@ int fcoe_ctlr_els_send(struct fcoe_ctlr *fip, struct fc_lport *lport, op = FIP_DT_FLOGI; if (fip->mode == FIP_MODE_VN2VN) break; - spin_lock_bh(&fip->ctlr_lock); + spin_lock_irqsave(&fip->ctlr_lock, flags); kfree_skb(fip->flogi_req); fip->flogi_req = skb; fip->flogi_req_send = 1; - spin_unlock_bh(&fip->ctlr_lock); + spin_unlock_irqrestore(&fip->ctlr_lock, flags); schedule_work(&fip->timer_work); return -EINPROGRESS; case ELS_FDISC: @@ -1723,10 +1725,11 @@ static int fcoe_ctlr_flogi_send_locked(struct fcoe_ctlr *fip) static int fcoe_ctlr_flogi_retry(struct fcoe_ctlr *fip) { struct fcoe_fcf *fcf; + unsigned long flags; int error; mutex_lock(&fip->ctlr_mutex); - spin_lock_bh(&fip->ctlr_lock); + spin_lock_irqsave(&fip->ctlr_lock, flags); LIBFCOE_FIP_DBG(fip, "re-sending FLOGI - reselect\n"); fcf = fcoe_ctlr_select(fip); if (!fcf || fcf->flogi_sent) { @@ -1737,7 +1740,7 @@ static int fcoe_ctlr_flogi_retry(struct fcoe_ctlr *fip) fcoe_ctlr_solicit(fip, NULL); error = fcoe_ctlr_flogi_send_locked(fip); } - spin_unlock_bh(&fip->ctlr_lock); + spin_unlock_irqrestore(&fip->ctlr_lock, flags); mutex_unlock(&fip->ctlr_mutex); return error; } @@ -1754,8 +1757,9 @@ static int fcoe_ctlr_flogi_retry(struct fcoe_ctlr *fip) static void fcoe_ctlr_flogi_send(struct fcoe_ctlr *fip) { struct fcoe_fcf *fcf; + unsigned long flags; - spin_lock_bh(&fip->ctlr_lock); + spin_lock_irqsave(&fip->ctlr_lock, flags); fcf = fip->sel_fcf; if (!fcf || !fip->flogi_req_send) goto unlock; @@ -1782,7 +1786,7 @@ static void fcoe_ctlr_flogi_send(struct fcoe_ctlr *fip) } else /* XXX */ LIBFCOE_FIP_DBG(fip, "No FCF selected - defer send\n"); unlock: - spin_unlock_bh(&fip->ctlr_lock); + spin_unlock_irqrestore(&fip->ctlr_lock, flags); } /** -- 2.40.1