From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 69F5C31E85C; Thu, 16 Jul 2026 13:56:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784210178; cv=none; b=A6Zp0EHNgSDcrMQhOTiVxSLRADNRdYJ/+fhEfnnP9h9XOqusj4FFeKiAYX8lUBOlCGS444NzRDIz/aPsdf10YwTO0AN+eNltR9hhNcS9CbiqfBvkx9LbrjJlA60/CHpQhBn1rmex7n8BR4Egvs4popylsbDPZlBCIrOHADJ/jck= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784210178; c=relaxed/simple; bh=iEBbpSWj0uXnMRamaaLfu9bkwPeM4LGxD9c5s1IqTUI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pM5Kxg2LY0vB0brU0lRRfyL+X2OA7MvwJRkFV/rHmBq6Mom8v8esO186AO+wxS+umRtgdKZsmxY7ZjURbj8wkL+9mlbOA8zASytkaz36NuL4EH4pKI+MS+GDfoWZ38h71hJ0YXOIY3lNd1rU0MgD0bhietrSTz4EruS67tHg5nw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=CwhpFgdT; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="CwhpFgdT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF6451F000E9; Thu, 16 Jul 2026 13:56:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784210177; bh=ltE2g6kBtbETMdQPsF9Ra0qUG/RuthKzdBdn582PMBU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CwhpFgdTxaiGotkRbg7vcjKZVvm88odolVpdx2cZ4vljEPKQQUCrFAzMOZZcAibE2 jsySVyfodH773UyA+VV+KmeWS6EQOZnS7IVMv4jxyx12u8qmSlQJi4SplDk7Xen4P1 rIr/AtQnrzxV30GhqK6z4V/N43Ky6wgNVqkhtSjg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chris Mason , Chuck Lever Subject: [PATCH 7.1 467/518] svcrdma: wake sq waiters when the transport closes Date: Thu, 16 Jul 2026 15:32:15 +0200 Message-ID: <20260716133058.062490481@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260716133047.772246337@linuxfoundation.org> References: <20260716133047.772246337@linuxfoundation.org> User-Agent: quilt/0.69 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 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chuck Lever commit e5248a7426030db1e126363f72afdb3b71339a5c upstream. Threads parked in svc_rdma_sq_wait() on sc_sq_ticket_wait or sc_send_wait can hang indefinitely in TASK_UNINTERRUPTIBLE state across transport teardown, pinning svc_xprt references and blocking svc_rdma_free(). The close path sets XPT_CLOSE before invoking xpo_detach and both wait_event predicates include an XPT_CLOSE term, but the predicates are re-evaluated only on wakeup. sc_sq_ticket_wait has no completion-driven wake path; it is advanced solely by the chained ticket handoff inside svc_rdma_sq_wait() itself. Without an explicit wake at close, parked threads never observe XPT_CLOSE, hold their svc_xprt_get reference forever, and svc_rdma_free() blocks on xpt_ref dropping to zero. Two close entry points reach this transport. Local teardown runs svc_rdma_detach() from svc_handle_xprt() -> svc_delete_xprt() -> xpo_detach() on a worker thread. A remote disconnect arrives at svc_rdma_cma_handler(), which calls svc_xprt_deferred_close(): that sets XPT_CLOSE and enqueues the transport but does not access either RDMA waitqueue, so a worker already parked in svc_rdma_sq_wait() never re-evaluates its predicate. With every worker parked on this transport, no thread is available to run the local teardown either, and the wake site there is unreachable. Introduce svc_rdma_xprt_deferred_close(), a thin svcrdma wrapper that calls svc_xprt_deferred_close() and then wakes both sc_sq_ticket_wait and sc_send_wait. Convert the svcrdma producers that called svc_xprt_deferred_close() directly: svc_rdma_cma_handler(), qp_event_handler(), svc_rdma_post_send_err(), svc_rdma_wc_send(), the sendto drop path, the rw completion error paths, and the recvfrom flush and read-list error paths. Wake both waitqueues from svc_rdma_detach() as well. The synchronous svc_xprt_close() path (backchannel ENOTCONN, device removal via svc_rdma_xprt_done) reaches detach without flowing through svc_xprt_deferred_close() and therefore does not invoke the new helper. Fixes: ccc89b9d1ed2 ("svcrdma: Add fair queuing for Send Queue access") Cc: stable@vger.kernel.org Assisted-by: kres (claude-opus-4-7) Signed-off-by: Chris Mason [ cel: add svc_rdma_xprt_deferred_close() to complete the fix ] Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman --- include/linux/sunrpc/svc_rdma.h | 1 + net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 4 ++-- net/sunrpc/xprtrdma/svc_rdma_rw.c | 6 +++--- net/sunrpc/xprtrdma/svc_rdma_sendto.c | 6 +++--- net/sunrpc/xprtrdma/svc_rdma_transport.c | 30 ++++++++++++++++++++++++++++-- 5 files changed, 37 insertions(+), 10 deletions(-) --- a/include/linux/sunrpc/svc_rdma.h +++ b/include/linux/sunrpc/svc_rdma.h @@ -328,6 +328,7 @@ extern int svc_rdma_result_payload(struc unsigned int length); /* svc_rdma_transport.c */ +extern void svc_rdma_xprt_deferred_close(struct svcxprt_rdma *rdma); extern struct svc_xprt_class svc_rdma_class; #ifdef CONFIG_SUNRPC_BACKCHANNEL extern struct svc_xprt_class svc_rdma_bc_class; --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c @@ -377,7 +377,7 @@ flushed: trace_svcrdma_wc_recv_err(wc, &ctxt->rc_cid); dropped: svc_rdma_recv_ctxt_put(rdma, ctxt); - svc_xprt_deferred_close(&rdma->sc_xprt); + svc_rdma_xprt_deferred_close(rdma); } /** @@ -1001,7 +1001,7 @@ out_readlist: if (ret == -EINVAL) svc_rdma_send_error(rdma_xprt, ctxt, ret); svc_rdma_recv_ctxt_put(rdma_xprt, ctxt); - svc_xprt_deferred_close(xprt); + svc_rdma_xprt_deferred_close(rdma_xprt); return ret; } return 0; --- a/net/sunrpc/xprtrdma/svc_rdma_rw.c +++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c @@ -313,7 +313,7 @@ static void svc_rdma_reply_done(struct i trace_svcrdma_wc_reply_err(wc, &cc->cc_cid); } - svc_xprt_deferred_close(&rdma->sc_xprt); + svc_rdma_xprt_deferred_close(rdma); } /** @@ -345,7 +345,7 @@ static void svc_rdma_write_done(struct i * some of the outgoing RPC message. Signal the loss * to the client by closing the connection. */ - svc_xprt_deferred_close(&rdma->sc_xprt); + svc_rdma_xprt_deferred_close(rdma); } /** @@ -390,7 +390,7 @@ static void svc_rdma_wc_read_done(struct */ svc_rdma_cc_release(rdma, cc, DMA_FROM_DEVICE); svc_rdma_recv_ctxt_put(rdma, ctxt); - svc_xprt_deferred_close(&rdma->sc_xprt); + svc_rdma_xprt_deferred_close(rdma); } /* --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c @@ -395,7 +395,7 @@ int svc_rdma_post_send_err(struct svcxpr int sqecount, int ret) { trace_svcrdma_sq_post_err(rdma, cid, ret); - svc_xprt_deferred_close(&rdma->sc_xprt); + svc_rdma_xprt_deferred_close(rdma); /* If even one WR was posted, a Send completion will * return the reserved SQ slots. @@ -437,7 +437,7 @@ flushed: else trace_svcrdma_wc_send_flush(wc, &ctxt->sc_cid); svc_rdma_send_ctxt_put(rdma, ctxt); - svc_xprt_deferred_close(&rdma->sc_xprt); + svc_rdma_xprt_deferred_close(rdma); } /** @@ -1158,7 +1158,7 @@ put_ctxt: svc_rdma_send_ctxt_put(rdma, sctxt); drop_connection: trace_svcrdma_send_err(rqstp, ret); - svc_xprt_deferred_close(&rdma->sc_xprt); + svc_rdma_xprt_deferred_close(rdma); return -ENOTCONN; } --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c @@ -98,10 +98,27 @@ struct svc_xprt_class svc_rdma_class = { .xcl_ident = XPRT_TRANSPORT_RDMA, }; +/** + * svc_rdma_xprt_deferred_close - Close an RDMA transport (deferred) + * @rdma: transport to close + */ +void svc_rdma_xprt_deferred_close(struct svcxprt_rdma *rdma) +{ + svc_xprt_deferred_close(&rdma->sc_xprt); + + /* Release parked sc_sq_ticket_wait and sc_send_wait waiters. + * Once XPT_CLOSE is observed each returns -ENOTCONN. + */ + wake_up_all(&rdma->sc_sq_ticket_wait); + wake_up_all(&rdma->sc_send_wait); +} + /* QP event handler */ static void qp_event_handler(struct ib_event *event, void *context) { struct svc_xprt *xprt = context; + struct svcxprt_rdma *rdma = + container_of(xprt, struct svcxprt_rdma, sc_xprt); trace_svcrdma_qp_error(event, (struct sockaddr *)&xprt->xpt_remote); switch (event->event) { @@ -119,7 +136,7 @@ static void qp_event_handler(struct ib_e case IB_EVENT_QP_ACCESS_ERR: case IB_EVENT_DEVICE_FATAL: default: - svc_xprt_deferred_close(xprt); + svc_rdma_xprt_deferred_close(rdma); break; } } @@ -340,7 +357,7 @@ static int svc_rdma_cma_handler(struct r svc_xprt_enqueue(xprt); break; case RDMA_CM_EVENT_DISCONNECTED: - svc_xprt_deferred_close(xprt); + svc_rdma_xprt_deferred_close(rdma); break; default: break; @@ -597,6 +614,15 @@ static void svc_rdma_detach(struct svc_x container_of(xprt, struct svcxprt_rdma, sc_xprt); rdma_disconnect(rdma->sc_cm_id); + + /* + * Most close paths go through svc_rdma_xprt_deferred_close(), + * which wakes the SQ waitqueues. svc_xprt_close() reaches + * detach without that helper, so wake any threads parked in + * svc_rdma_sq_wait() here as well. + */ + wake_up_all(&rdma->sc_sq_ticket_wait); + wake_up_all(&rdma->sc_send_wait); } /**