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 F1BBB3033F4; Wed, 28 Jan 2026 15:55:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769615747; cv=none; b=nTtKcHCk+jjmwBa+a+LC7UdkCXpD4mVOSxnsZh56vqEd/TUubme22PDv9gjzaeg2VoiMF4N/XaBCUUiuUfQWHqcEhE2APhc5yO2MgptVSlkgCpno2BLx/oWfjCiTYo3niQVCR2gfIMgREvluYiQKz2C5jyaOmY1g4rUOHQciAP8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769615747; c=relaxed/simple; bh=CnyOi5V25s2N7gskAcNF8EsCYV9QC1GdlAdsUB6cFRY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mazaYRNRvjMnf3AT6MGmKuu79uvC1+AtUIcCwTXaIa6AI2ajd/cjaQk1dGmzz16b5Tl+9QaeKutCpZATsIII+pOl6aVbMQ2P1AkNXkz+CE4wuDRnAoBK/XINe5eG7jIXkc1nuLuFK6/WLSx37C5scUWs0CnMpk1bePiBbYH/zZM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=P69JdpNc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="P69JdpNc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17389C4CEF1; Wed, 28 Jan 2026 15:55:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1769615746; bh=CnyOi5V25s2N7gskAcNF8EsCYV9QC1GdlAdsUB6cFRY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=P69JdpNc0ixJbm31Fy3/pRZPKZivfrHl5GrSeOu0j3rsNBHxfzYCAeQ/88CCR3SwB 5V1zRMWEZzL+l+b86/mtfRcK6G9DU3DXjlHzv2pjUaka4QChMtGJJ3J5GmvKg7XKEZ bsEmDCNcChEp8DYeevAnZBUydiFYpcsnKbzyCXho= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Faith , Pumpkin Chang , David Howells , Marc Dionne , Nir Ohfeld , Willy Tarreau , Simon Horman , linux-afs@lists.infradead.org, stable@kernel.org, Jakub Kicinski Subject: [PATCH 6.18 069/227] rxrpc: Fix recvmsg() unconditional requeue Date: Wed, 28 Jan 2026 16:21:54 +0100 Message-ID: <20260128145346.823162493@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260128145344.331957407@linuxfoundation.org> References: <20260128145344.331957407@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org 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: David Howells commit 2c28769a51deb6022d7fbd499987e237a01dd63a upstream. If rxrpc_recvmsg() fails because MSG_DONTWAIT was specified but the call at the front of the recvmsg queue already has its mutex locked, it requeues the call - whether or not the call is already queued. The call may be on the queue because MSG_PEEK was also passed and so the call was not dequeued or because the I/O thread requeued it. The unconditional requeue may then corrupt the recvmsg queue, leading to things like UAFs or refcount underruns. Fix this by only requeuing the call if it isn't already on the queue - and moving it to the front if it is already queued. If we don't queue it, we have to put the ref we obtained by dequeuing it. Also, MSG_PEEK doesn't dequeue the call so shouldn't call rxrpc_notify_socket() for the call if we didn't use up all the data on the queue, so fix that also. Fixes: 540b1c48c37a ("rxrpc: Fix deadlock between call creation and sendmsg/recvmsg") Reported-by: Faith Reported-by: Pumpkin Chang Signed-off-by: David Howells Acked-by: Marc Dionne cc: Nir Ohfeld cc: Willy Tarreau cc: Simon Horman cc: linux-afs@lists.infradead.org cc: stable@kernel.org Link: https://patch.msgid.link/95163.1768428203@warthog.procyon.org.uk Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- include/trace/events/rxrpc.h | 4 ++++ net/rxrpc/recvmsg.c | 19 +++++++++++++++---- 2 files changed, 19 insertions(+), 4 deletions(-) --- a/include/trace/events/rxrpc.h +++ b/include/trace/events/rxrpc.h @@ -322,6 +322,7 @@ EM(rxrpc_call_put_kernel, "PUT kernel ") \ EM(rxrpc_call_put_poke, "PUT poke ") \ EM(rxrpc_call_put_recvmsg, "PUT recvmsg ") \ + EM(rxrpc_call_put_recvmsg_peek_nowait, "PUT peek-nwt") \ EM(rxrpc_call_put_release_recvmsg_q, "PUT rls-rcmq") \ EM(rxrpc_call_put_release_sock, "PUT rls-sock") \ EM(rxrpc_call_put_release_sock_tba, "PUT rls-sk-a") \ @@ -340,6 +341,9 @@ EM(rxrpc_call_see_input, "SEE input ") \ EM(rxrpc_call_see_notify_released, "SEE nfy-rlsd") \ EM(rxrpc_call_see_recvmsg, "SEE recvmsg ") \ + EM(rxrpc_call_see_recvmsg_requeue, "SEE recv-rqu") \ + EM(rxrpc_call_see_recvmsg_requeue_first, "SEE recv-rqF") \ + EM(rxrpc_call_see_recvmsg_requeue_move, "SEE recv-rqM") \ EM(rxrpc_call_see_release, "SEE release ") \ EM(rxrpc_call_see_userid_exists, "SEE u-exists") \ EM(rxrpc_call_see_waiting_call, "SEE q-conn ") \ --- a/net/rxrpc/recvmsg.c +++ b/net/rxrpc/recvmsg.c @@ -518,7 +518,8 @@ try_again: if (rxrpc_call_has_failed(call)) goto call_failed; - if (!skb_queue_empty(&call->recvmsg_queue)) + if (!(flags & MSG_PEEK) && + !skb_queue_empty(&call->recvmsg_queue)) rxrpc_notify_socket(call); goto not_yet_complete; @@ -549,11 +550,21 @@ error_unlock_call: error_requeue_call: if (!(flags & MSG_PEEK)) { spin_lock_irq(&rx->recvmsg_lock); - list_add(&call->recvmsg_link, &rx->recvmsg_q); - spin_unlock_irq(&rx->recvmsg_lock); + if (list_empty(&call->recvmsg_link)) { + list_add(&call->recvmsg_link, &rx->recvmsg_q); + rxrpc_see_call(call, rxrpc_call_see_recvmsg_requeue); + spin_unlock_irq(&rx->recvmsg_lock); + } else if (list_is_first(&call->recvmsg_link, &rx->recvmsg_q)) { + spin_unlock_irq(&rx->recvmsg_lock); + rxrpc_put_call(call, rxrpc_call_see_recvmsg_requeue_first); + } else { + list_move(&call->recvmsg_link, &rx->recvmsg_q); + spin_unlock_irq(&rx->recvmsg_lock); + rxrpc_put_call(call, rxrpc_call_see_recvmsg_requeue_move); + } trace_rxrpc_recvmsg(call_debug_id, rxrpc_recvmsg_requeue, 0); } else { - rxrpc_put_call(call, rxrpc_call_put_recvmsg); + rxrpc_put_call(call, rxrpc_call_put_recvmsg_peek_nowait); } error_no_call: release_sock(&rx->sk);