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 C8236287247; Sat, 11 Jul 2026 16:54:20 +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=1783788861; cv=none; b=RuURI20h4ahKVi0rQ72tKyK91PwD2+eAwz5MueCkDFwO1NSOXni3SxILZa6o43y5TQwSauUSOiJta8EOhUmfQRZpCfZwxcHfRrK6exJFo63VJkBnJIw2T2EzPy5GnAZQSa///RcNl1m7R4DsfBhllF/OIwst8qgaO5Zj5ildufM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783788861; c=relaxed/simple; bh=RPG4mK1iavRNNS/of6gO5cwEu5csBBoQKZmKdSLLxY0=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=os4yPLu5B07wfEyM4FeA970XVDvP6AfvOrgRBxpIhnJEI/yPeC6AahWrobdXqzOcO40dUHNvQokWu4BIAerCL0rbjehFj5sRrGlRYMRwIlRCT5YEIOm501WdaRyHKeIDNV+pih8oGlejDtbr/vp05j5tXy+cyha/ugnccxbwyAI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Mn1iK46k; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Mn1iK46k" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C9721F000E9; Sat, 11 Jul 2026 16:54:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783788860; bh=6uAeZnUIlVawIsyK/ey6kUbvgIVzicvXV8yWYRQ/FWU=; h=From:To:Cc:Subject:Date; b=Mn1iK46k19EV89VDyHaEV0oZTKMSvmjxIxuKOaLXJO2dVnZcLXkOq35YLlwtfVmOg NupyE0DdkHONwq4eNStSaj35jKzhJJ+bDikc4CGQLoYpcZGCGHVL2/Y71DShbOffEF 6XU4s3b7ar6QOkyuM0M8T/jBNvxiB5QkCjWdVxGmybLBe7NmaKYfU18KtEm6LhXKSO iNRN8CFoDEL7sRDQimmxZqAG5cpMR5JPGdWcGsBE24G9+T9OyUQe4amGLci5NA4cR9 eb/3YmEQJhvbZj5H7WrEsmNc3sxjXCau+p4edNnPtQzWRpe9QoAYjesAW92D2QdUdi hX/9H9BfnZqGQ== From: Allison Henderson To: Zhu Yanjun , Jason Gunthorpe , Leon Romanovsky Cc: Bob Pearson , Ian Ziemba , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, Allison Henderson Subject: [PATCH for-rc] RDMA/rxe: don't re-execute the current packet after the QP moved to error state Date: Sat, 11 Jul 2026 09:54:19 -0700 Message-Id: <20260711165419.13486-1-achender@kernel.org> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When do_complete() finds the QP in the error state it returns RESPST_CHK_RESOURCE. Before commit 49dc9c1f0c7e ("RDMA/rxe: Cleanup reset state handling in rxe_resp.c") this was the flush loop: check_resource() had an error-state branch that fetched each remaining recv WQE and completed it with IB_WC_WR_FLUSH_ERR, without touching the current packet. That commit removed the error-state branch from check_resource() (draining is now done at rxe_receiver() entry) but kept the do_complete() error-state return. As a result, when a QP moves to the error state while a packet is being completed - e.g. an rdma_cm disconnect racing with receive processing - the responder state machine loops back into the request processing chain with the already-completed packet still in hand: check_resource() fetches a fresh recv WQE, execute()/send_data_in() copies the same packet payload again, do_complete() posts another IB_WC_SUCCESS CQE (qp->resp.status is still 0), and control returns to the error-state check. The loop re-executes the same packet once per posted recv WQE (observed: ~1000 duplicate IB_WC_SUCCESS completions of one SEND, one per ~8us, matching the RQ occupancy) until the RQ is exhausted, after which qp->resp.wqe is NULL and send_data_in() dereferences it: BUG: kernel NULL pointer dereference, address: 0000000000000014 Workqueue: rxe_wq do_work RIP: copy_data+0x29/0x1f0 Call Trace: send_data_in+0x25/0x50 rxe_receiver+0xf36/0x1dd0 The duplicate completions are indistinguishable from real receives to the ULP. During an rds stress test, the message was accepted as new and delivered the same datagram to user space hundreds of times, corrupting the stream; any ULP that relies on RC exactly-once delivery is affected. A live packet reaching the error-state check in do_complete() has been executed and completed exactly once and must be consumed, not re-processed. Return RESPST_CLEANUP for it (dequeue and free); keep returning RESPST_CHK_RESOURCE for the pkt == NULL case. Fixes: 49dc9c1f0c7e ("RDMA/rxe: Cleanup reset state handling in rxe_resp.c") Assisted-by: Claude-Code:claude-fable-5 Signed-off-by: Allison Henderson --- drivers/infiniband/sw/rxe/rxe_resp.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c index d8cbdfa70cdbd..02b16e2b49b8f 100644 --- a/drivers/infiniband/sw/rxe/rxe_resp.c +++ b/drivers/infiniband/sw/rxe/rxe_resp.c @@ -1217,7 +1217,14 @@ static enum resp_states do_complete(struct rxe_qp *qp, spin_lock_irqsave(&qp->state_lock, flags); if (unlikely(qp_state(qp) == IB_QPS_ERR)) { spin_unlock_irqrestore(&qp->state_lock, flags); - return RESPST_CHK_RESOURCE; + /* The packet was executed and completed before the QP + * moved to ERROR; it must be consumed exactly once. + * Re-entering the request chain with the stale packet + * would copy it into every remaining recv WQE as a new + * completion. Remaining WQEs are flushed by the drain + * path at rxe_receiver() entry. + */ + return pkt ? RESPST_CLEANUP : RESPST_CHK_RESOURCE; } spin_unlock_irqrestore(&qp->state_lock, flags); -- 2.25.1