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 4A98341A56F; Fri, 4 Sep 2026 05:22:07 +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=1788499328; cv=none; b=QaLtY7rZRShTqsckiexGkZtKJKWPEw0E76hzW+74AFYUb/oMeUfAPE1CAbBN7YA0ptytrFyCavJpBP7zibIaiEZJVf7xUXTczBN6fTsLlSOxyvBUeARSk1ZfaG1HjNRqG3Ml+wW1Q02mp0//WBZC/7mSVdutG4GYx6HTnvNV4TQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788499328; c=relaxed/simple; bh=prIQlDiLeQnNP1mkp/M4zNCg7xu3A7BAicMFD0hNL10=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=SrG5IzsONaV/kMKvmPUcXDcFc4c4jBV0KVtyHytUefqy3QsLnOVjVqCGiP5/A2hW7wlvCHLoh2+LFYocAPIoRZ40zAW/qXkceR4p1KZmVxr7pa/UvkEJxcZsExXjn5DF13AlXp30ktXgH2fvbk1JpL1uwnrhSGUGSL2Kq0qxcd0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UrmR9oF9; 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="UrmR9oF9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C2AF1F00A3F; Fri, 4 Sep 2026 05:22:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788499327; bh=RZimqwaTuHSTXm/s7en9sM2Xk9dCFsKApGcp8q6lIAc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=UrmR9oF9tYEPsbCMtA9/pjBQAwZEJRyv2MTBLwiAEWNP1GCSsGOLA/SjtVohjbzhp GF05a9HZKVq2q8RhLNWzdv0viPqc9Z5siWe48ozJn3/4w5QCqsOWSZgtdZwrFI+qaa jsVAdRtsHQY4XKJUIgODPrv1hfKL3xPihl7WrpDc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jeff Layton , Chuck Lever Subject: [PATCH 7.2 378/713] sunrpc: defer rq_argp and rq_resp free until after RCU grace period Date: Fri, 4 Sep 2026 06:55:46 +0200 Message-ID: <20260904045812.299851101@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045803.810145556@linuxfoundation.org> References: <20260904045803.810145556@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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jeff Layton commit c479bde671cbe2f9e152834a8b0eb7c3c295bbaf upstream. svc_rqst_free() frees rqstp->rq_argp and rqstp->rq_resp synchronously via kfree(), but defers the rqstp struct free via kfree_rcu(). After svc_exit_thread() calls list_del_rcu() and svc_rqst_free(), there is a window where RCU readers that started before list_del_rcu() can still traverse the thread list and find the rqstp. These readers (e.g. nfsd_nl_rpc_status_get_dumpit()) dereference rqstp->rq_argp, which has already been freed — a use-after-free. Fix this by moving the kfree of rq_argp and rq_resp into an explicit call_rcu() callback alongside the struct free. Resources not accessed by RCU readers (bvec, buffer pages, scratch folio, auth_data) remain synchronously freed. Fixes: 812443865c5f ("sunrpc: add a rcu_head to svc_rqst and use kfree_rcu to free it") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Jeff Layton Link: https://patch.msgid.link/20260611-nfsd-testing-v2-4-5b90e276f2d9@kernel.org Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman --- net/sunrpc/svc.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -743,6 +743,15 @@ svc_release_buffer(struct svc_rqst *rqst } } +static void svc_rqst_free_rcu(struct rcu_head *head) +{ + struct svc_rqst *rqstp = container_of(head, struct svc_rqst, rq_rcu_head); + + kfree(rqstp->rq_resp); + kfree(rqstp->rq_argp); + kfree(rqstp); +} + static void svc_rqst_free(struct svc_rqst *rqstp) { @@ -751,10 +760,8 @@ svc_rqst_free(struct svc_rqst *rqstp) svc_release_buffer(rqstp); if (rqstp->rq_scratch_folio) folio_put(rqstp->rq_scratch_folio); - kfree(rqstp->rq_resp); - kfree(rqstp->rq_argp); kfree(rqstp->rq_auth_data); - kfree_rcu(rqstp, rq_rcu_head); + call_rcu(&rqstp->rq_rcu_head, svc_rqst_free_rcu); } static struct svc_rqst *