From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f54.google.com (mail-wr1-f54.google.com [209.85.221.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 322793914EB for ; Wed, 7 Oct 2026 22:32:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.54 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791412355; cv=none; b=QbNY7zh+oxA4XkYECM+UZXWm61rShltSSzCiFYjK0qWdyf14BnCF11g5BTV6+KW7EN8eq/Ljrp2Kdq2Ek6PUH8mK9VSNZbqfyvB0aQRhwpTdd5phYdYY73sNADSs3uT/BOWd6AOoq9Z71GIrF5TUlE+UUIoJIXJqNaptombfj8A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791412355; c=relaxed/simple; bh=8+U5D2e5SYzZrGrK1iL1HrfwBcX1Qkb57io62ZvQyms=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XKdwvL4LMDTK4ELX6ox7HuM4I/HQTmpF4EDN67/fpL+SJi5U9Sg9wxb2lP8axEIAu3wFyK01s6hCoUdL1ZXOr+7y9XkJzmlk2UFglaRcqrLdgAxc0Bm/EzYuvyj3qO55jVPTgHoSlCtH+DjGZKuGYg7mZzQT5FTpXaq3MpM/4e8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=BNGdMFKk; arc=none smtp.client-ip=209.85.221.54 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BNGdMFKk" Received: by mail-wr1-f54.google.com with SMTP id ffacd0b85a97d-48c14a06c95so1894075f8f.1 for ; Wed, 07 Oct 2026 15:32:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1791412351; x=1792017151; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=ijnB+OFRCY2MBDBmpyYwGFKzVgbk/JgZe3RlorNey9w=; b=BNGdMFKk58gaT3jjcwzDxxRlH8sWxuMmQel35qZfTOGZYQZS4E33wksR86SdYNoA+S S/jlJqf50D9+xlv7m20j2tunQSbngJubUkozLyPqPwguJPdTHZwzEjtBFLXn0oPSPoKp Nw//cyiiGCxhWUVnqQGxDPPVSDFg+XPlSWBH8qGoXp3b3HkkB71aJW47Ij9f59PsZKJh gumS6QxXhAUB8jwyCGudqjt5Q4DxEeVmQMAIWfwELFDVK6PP+X6RffgWeW8w4iUADJrf uENasNX9J/zGyAikFmSEKn3qIQJZrXxreJRlbD6xSrUVB3etpUhAjMQGYHkP7YO7c5rt 0igg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791412351; x=1792017151; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=ijnB+OFRCY2MBDBmpyYwGFKzVgbk/JgZe3RlorNey9w=; b=DQ+ofEK+rL9UQJhDeOh/Rbbp6KJl3gGWRxlbARyeNWaGaejxp3uqRycaE3JlcK6+p4 qDzmwwn50SMPPkWCAjIbG07WnN1OO/LbxGhcxK2bjKKefehNbaqWr8lKHe8S4fxJ3rTp VqBeBQL7gMevUWrC40TRNJL0N4bmupO/1g89XtRUJWTHoprn6wyqzUKEf6GPNajG8Zjl N8DlUXXtCZVyH2nVFjofNbMLXd/E98QTHZDtqa3KBdXw5uXEn/PZRTTiI+5g2sLInQ9v dbA2GjRw9n/qlm+yV0biyzVgmfjF8NXIg99c+A9byqHRILwIvyZd/uNLpIhiGBEougqh N1PA== X-Gm-Message-State: AFq9FYKcmw0NUbqX16o+uihHwcKNzFJyRgkdGr8g3wehfQrrD+mM1RF7 f2JsOry0pQhPCnPgHirsj8h40svWLwqrl3rX46qTU6UpXaHsruzU+UuiwfGQ X-Gm-Gg: AYBFou3c8IJX6qvftMccc3Zktg1JUAdZkpPJ9FKZQsLzljApunF9p6qqRyMyr4YHcNl 38+3s1plNNaiTxJbB5fapoBCAIyvVsQM4Q3R3/mprIedGWMpOsrsjlW5xEKyjZpUA91VETt1Gpt s3Fk2+QGlCL3TX77PxwEbdreevq7OP189bz/t+EGNr8abKEOUnP/xZtg7mFW8h+lwYqypJF4+4x wOb4MHzQwCVAMgPuEy/HnPYmpFdLYavsmEY38tnW7q0depnIsF7bMNDzZIKk6z686HTMTELmIuU SAiI8UO1KYuH2Pw3QYQUHJd86N0bXA+dUnI7oRTG5z6dMF2xJumMQIW0XDiXqhijn6OI2VHd+ne ULtL5D1LyKMWIO2lCtghzUUvFeGy424wE8EvsvnGl5KRRTEaVMSExYd2k6/e5QPpz0/GdOgovSt mAQH2xupPF+S0wijfp6JB9WgAHJBMu+l/Za6X/+HM= X-Received: by 2002:a05:6000:26c8:b0:48a:fc9a:3765 with SMTP id ffacd0b85a97d-48c7289b124mr7353204f8f.46.1791412351306; Wed, 07 Oct 2026 15:32:31 -0700 (PDT) Received: from debian.. ([2001:41d0:303:db6b::]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-48c71d1fec3sm7743500f8f.37.2026.10.07.15.32.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Oct 2026 15:32:30 -0700 (PDT) From: Tristan Madani To: linux-rdma@vger.kernel.org Cc: jgg@ziepe.ca, leon@kernel.org, zyjzyj2000@gmail.com, bob.pearson@hpe.com, Tristan Madani , stable@vger.kernel.org Subject: [PATCH v4 2/2] RDMA/rxe: copy send WQE to kernel buffer in completer path Date: Wed, 7 Oct 2026 22:32:22 +0000 Message-ID: <20261007223222.2342804-3-tristmd@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261007223222.2342804-1-tristmd@gmail.com> References: <20261007223222.2342804-1-tristmd@gmail.com> Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Tristan Madani The completer reads send WQEs from the same userspace-mapped shared queue as the requester. Even after the requester copies the WQE to a kernel-private buffer (previous patch), the completer still reads directly from shared memory, leaving it exposed to the same TOCTOU races. Fix by copying the WQE in get_wqe() to a completer-private buffer using the full queue element size (max_sge SGEs). The local copy is reused when the same WQE is being processed with unchanged state, which preserves DMA progress across multi-packet RDMA READ responses. A fresh copy is taken when the state changes or a new WQE appears. State transitions from the requester are observed through an smp_load_acquire() / smp_store_release() pair. Completion status and rd_atomic state are written back through WRITE_ONCE() before the consumer index advances. The copy is invalidated on QP reset and when the completion advances to the next WQE. Fixes: 8700e3e7c485 ("Soft RoCE driver") Cc: stable@vger.kernel.org Signed-off-by: Tristan Madani --- drivers/infiniband/sw/rxe/rxe_comp.c | 53 ++++++++++++++++++++++++++- drivers/infiniband/sw/rxe/rxe_qp.c | 1 + drivers/infiniband/sw/rxe/rxe_verbs.h | 6 +++ 3 files changed, 58 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/sw/rxe/rxe_comp.c b/drivers/infiniband/sw/rxe/rxe_comp.c index 1390e861bd1d7..ca31093fdf3aa 100644 --- a/drivers/infiniband/sw/rxe/rxe_comp.c +++ b/drivers/infiniband/sw/rxe/rxe_comp.c @@ -137,22 +137,69 @@ void rxe_comp_queue_pkt(struct rxe_qp *qp, struct sk_buff *skb) rxe_sched_task(&qp->send_task); } +/* Write back completer WQE fields to shared memory */ +static void rxe_comp_writeback_wqe(struct rxe_qp *qp) +{ + struct rxe_send_wqe *shared = qp->comp.shared_wqe; + struct rxe_send_wqe *local = &qp->comp.comp_wqe.wqe; + + if (!qp->comp.comp_wqe_valid || !shared) + return; + + WRITE_ONCE(shared->status, local->status); + WRITE_ONCE(shared->has_rd_atomic, local->has_rd_atomic); +} + static inline enum comp_state get_wqe(struct rxe_qp *qp, struct rxe_pkt_info *pkt, struct rxe_send_wqe **wqe_p) { struct rxe_send_wqe *wqe; + u32 state; /* we come here whether or not we found a response packet to see if * there are any posted WQEs */ wqe = queue_head(qp->sq.queue, QUEUE_TYPE_FROM_CLIENT); - *wqe_p = wqe; /* no WQE or requester has not started it yet */ - if (!wqe || wqe->state == wqe_state_posted) + if (!wqe) { + *wqe_p = NULL; return pkt ? COMPST_DONE : COMPST_EXIT; + } + + /* Pairs with smp_store_release() in rxe_req_writeback_wqe() */ + state = smp_load_acquire(&wqe->state); + if (state == wqe_state_posted) { + *wqe_p = wqe; + return pkt ? COMPST_DONE : COMPST_EXIT; + } + + /* Reuse existing local copy if still processing same WQE + * with unchanged state (preserves DMA progress for multi-packet ops) + */ + if (qp->comp.comp_wqe_valid && qp->comp.shared_wqe == wqe && + qp->comp.comp_wqe.wqe.state == state) { + wqe = &qp->comp.comp_wqe.wqe; + *wqe_p = wqe; + goto check_state; + } + + /* Copy shared WQE to kernel-private buffer. Copy the full + * element (max_sge SGEs) so that inline data, which shares + * the flex array with SGEs, is always captured. + */ + qp->comp.shared_wqe = wqe; + memcpy(&qp->comp.comp_wqe.wqe, wqe, + sizeof(*wqe) + qp->sq.max_sge * sizeof(struct rxe_sge)); + qp->comp.comp_wqe_valid = true; + if (qp->comp.comp_wqe.wqe.dma.num_sge > qp->sq.max_sge) + qp->comp.comp_wqe.wqe.dma.num_sge = qp->sq.max_sge; + + wqe = &qp->comp.comp_wqe.wqe; + *wqe_p = wqe; +check_state: /* WQE does not require an ack */ if (wqe->state == wqe_state_done) return COMPST_COMP_WQE; @@ -454,6 +501,8 @@ static void do_complete(struct rxe_qp *qp, struct rxe_send_wqe *wqe) if (post) make_send_cqe(qp, wqe, &cqe); + rxe_comp_writeback_wqe(qp); + qp->comp.comp_wqe_valid = false; queue_advance_consumer(qp->sq.queue, QUEUE_TYPE_FROM_CLIENT); if (post) diff --git a/drivers/infiniband/sw/rxe/rxe_qp.c b/drivers/infiniband/sw/rxe/rxe_qp.c index 77606c4a039b1..450254a131017 100644 --- a/drivers/infiniband/sw/rxe/rxe_qp.c +++ b/drivers/infiniband/sw/rxe/rxe_qp.c @@ -582,6 +582,7 @@ static void rxe_qp_reset(struct rxe_qp *qp) qp->req.wait_for_rnr_timer = 0; qp->req.noack_pkts = 0; qp->req.send_wqe_valid = false; + qp->comp.comp_wqe_valid = false; qp->resp.msn = 0; qp->resp.opcode = -1; qp->resp.drop_msg = 0; diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.h b/drivers/infiniband/sw/rxe/rxe_verbs.h index a22dfc6e5ae3c..6205dbc29dff6 100644 --- a/drivers/infiniband/sw/rxe/rxe_verbs.h +++ b/drivers/infiniband/sw/rxe/rxe_verbs.h @@ -130,6 +130,12 @@ struct rxe_comp_info { int started_retry; u32 retry_cnt; u32 rnr_retry; + struct rxe_send_wqe *shared_wqe; + bool comp_wqe_valid; + struct { + struct rxe_send_wqe wqe; + struct ib_sge sge[RXE_MAX_SGE]; + } comp_wqe; }; /* responder states */ -- 2.47.3