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 503995381 for ; Mon, 19 Jun 2023 10:46:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC38FC433CC; Mon, 19 Jun 2023 10:46:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1687171609; bh=83rw+pcpfln0desEQ7PngDJJgQedTNe2tIna+kndp0A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RmFywQu1yJwCjMweMgMm9TPjb4s6VVUHoGxWWkwPl2V91WRYbjJK+TdSSYloDQcmK Ikmtz60QhDaJOq0b9JUVoSCYwKRuESwwYDP5Ayr17L9NGEseTk6nVVM3vh+CgSyhEk 2Tf4SWUmLgsGS3byADsnypIlvwsBCu2DxBBn/YY4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Bob Pearson , Jason Gunthorpe , Sasha Levin Subject: [PATCH 6.1 093/166] RDMA/rxe: Fix ref count error in check_rkey() Date: Mon, 19 Jun 2023 12:29:30 +0200 Message-ID: <20230619102159.313337812@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230619102154.568541872@linuxfoundation.org> References: <20230619102154.568541872@linuxfoundation.org> User-Agent: quilt/0.67 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 From: Bob Pearson [ Upstream commit b00683422fd79dd07c9b75efdce1660e5e19150e ] There is a reference count error in error path code and a potential race in check_rkey() in rxe_resp.c. When looking up the rkey for a memory window the reference to the mw from rxe_lookup_mw() is dropped before a reference is taken on the mr referenced by the mw. If the mr is destroyed immediately after the call to rxe_put(mw) the mr pointer is unprotected and may end up pointing at freed memory. The rxe_get(mr) call should take place before the rxe_put(mw) call. All errors in check_rkey() call rxe_put(mw) if mw is not NULL but it was already called after the above. The mw pointer should be set to NULL after the rxe_put(mw) call to prevent this from happening. Fixes: cdd0b85675ae ("RDMA/rxe: Implement memory access through MWs") Link: https://lore.kernel.org/r/20230517211509.1819998-1-rpearsonhpe@gmail.com Signed-off-by: Bob Pearson Signed-off-by: Jason Gunthorpe Signed-off-by: Sasha Levin --- drivers/infiniband/sw/rxe/rxe_resp.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c index 693081e813ec0..9f65c346d8432 100644 --- a/drivers/infiniband/sw/rxe/rxe_resp.c +++ b/drivers/infiniband/sw/rxe/rxe_resp.c @@ -466,8 +466,9 @@ static enum resp_states check_rkey(struct rxe_qp *qp, if (mw->access & IB_ZERO_BASED) qp->resp.offset = mw->addr; - rxe_put(mw); rxe_get(mr); + rxe_put(mw); + mw = NULL; } else { mr = lookup_mr(qp->pd, access, rkey, RXE_LOOKUP_REMOTE); if (!mr) { -- 2.39.2