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 159F144DB64; Tue, 16 Jun 2026 15:58:03 +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=1781625484; cv=none; b=eIRvAZ/T1GaYnD9BO6oWuRQCkfA3bRggc7WAkvv10Jn2A2YeWjy6+W1OOsF598Sq3npM7IgbV6pPSHvyw1EGfZr1yH1eRoJjW/i3MMLVCSQfOIWHnlMYGEjjcwI7oBOZ3+Ghn52S3uwycz/ghwR3KW7s5mtV0vQNtMpecGWy75A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781625484; c=relaxed/simple; bh=eLd8GE2EHoIb1GOMvxTE3TB1eelAGeP4K3M6vLr9hhc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=e46XeyC6ceKJI/+GAK41Kzio08tZD/X93fOqCpy5VhVpQi1CV5ysoSwd9cDvIV6XllygfPXoB2xKeCZa2DN9mwj7aS0vzS0L0O4/CDlAEwgOpvTU/rx7oxK233yxBuEH+gUniD+07MpMCOILJrfOrSCf1myhzkVr12+dIbW1wec= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Sbo3/z8P; 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="Sbo3/z8P" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1ACE51F00A3D; Tue, 16 Jun 2026 15:58:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781625483; bh=Hugzu143pBXspy7P/zv1v3puXUv1hCL3anxq/gQusxk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Sbo3/z8PqMktHCxoKbtZQ85aQnD/5Ep1oKHPMD9AH8zfNE9gWg3McffSMQUGIuYaV 6qRqVaI/8DaXDnwAeHCeDWNRZ83lzhHmsXmfPEKIDM3+o4ZYa+SnL1wPpGgr2bZI8s flIkINr2MUF0rCd0k1uDBHbOn5Qg41/syBPrw/aU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xiang Mei , Weiming Shi , Allison Henderson , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 119/325] net/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion Date: Tue, 16 Jun 2026 20:28:35 +0530 Message-ID: <20260616145103.643641707@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145057.827196531@linuxfoundation.org> References: <20260616145057.827196531@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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Weiming Shi [ Upstream commit 34080db3e70ddf94c38512ad2331e3c3afca6cc1 ] rds_ib_xmit_atomic() always programs a masked atomic opcode (IB_WR_MASKED_ATOMIC_CMP_AND_SWP or IB_WR_MASKED_ATOMIC_FETCH_AND_ADD) for every RDS atomic cmsg. But the completion-side switch in rds_ib_send_unmap_op() only handles the non-masked opcodes, so a masked atomic completion falls through to default and returns rm == NULL while send->s_op is left set. rds_ib_send_cqe_handler() then dereferences the NULL rm via rm->m_final_op, oopsing in softirq context. An unprivileged AF_RDS sendmsg() of an atomic cmsg over an active RDS/IB connection triggers it; on hardware that natively accepts masked atomics (mlx4, mlx5) no extra setup is needed. RDS/IB: rds_ib_send_unmap_op: unexpected opcode 0xd in WR! Oops: general protection fault [#1] SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000190-0x0000000000000197] RIP: rds_ib_send_cqe_handler+0x25c/0xb10 (net/rds/ib_send.c:282) Call Trace: rds_ib_send_cqe_handler (net/rds/ib_send.c:282) poll_scq (net/rds/ib_cm.c:274) rds_ib_tasklet_fn_send (net/rds/ib_cm.c:294) tasklet_action_common (kernel/softirq.c:943) handle_softirqs (kernel/softirq.c:573) run_ksoftirqd (kernel/softirq.c:479) Kernel panic - not syncing: Fatal exception in interrupt Handle the masked atomic opcodes in the same case as the non-masked ones: they map to the same struct rds_message.atomic union member, so the existing container_of()/rds_ib_send_unmap_atomic() body is correct for them. Fixes: 20c72bd5f5f9 ("RDS: Implement masked atomic operations") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Reviewed-by: Allison Henderson Link: https://patch.msgid.link/20260606192447.1179255-2-bestswngs@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/rds/ib_send.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/rds/ib_send.c b/net/rds/ib_send.c index 4190b90ff3b18a..1909cd440a4b66 100644 --- a/net/rds/ib_send.c +++ b/net/rds/ib_send.c @@ -170,6 +170,8 @@ static struct rds_message *rds_ib_send_unmap_op(struct rds_ib_connection *ic, break; case IB_WR_ATOMIC_FETCH_AND_ADD: case IB_WR_ATOMIC_CMP_AND_SWP: + case IB_WR_MASKED_ATOMIC_FETCH_AND_ADD: + case IB_WR_MASKED_ATOMIC_CMP_AND_SWP: if (send->s_op) { rm = container_of(send->s_op, struct rds_message, atomic); rds_ib_send_unmap_atomic(ic, send->s_op, wc_status); -- 2.53.0