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Thread-Topic: net/sunrpc/xprtrdma/frwr_ops.c:647 frwr_unmap_async() error: potentially dereferencing uninitialized 'last'. 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charset="us-ascii" Content-ID: <0FBBB61E3DF7634DA3B4471BAC3C8FAC@namprd10.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: SJ0PR10MB4688.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: e1c3e46a-a9de-4dbf-22fb-08d936413f2c X-MS-Exchange-CrossTenant-originalarrivaltime: 23 Jun 2021 12:20:10.8992 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: xzZb5QV1LM3Ugd4da95AVoSobwJS1Ihe4MM1gG2jukA8icSOVxucQkH28dWSKhfQG3io6mgOc9ivfrzCmCY6yA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR10MB4688 X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=10023 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 mlxscore=0 adultscore=0 mlxlogscore=999 phishscore=0 suspectscore=0 bulkscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2106230071 X-Proofpoint-ORIG-GUID: phbfov9UKrJeyBEoXbVLu5a4dJo1gPlA X-Proofpoint-GUID: phbfov9UKrJeyBEoXbVLu5a4dJo1gPlA Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Howdy Dan! > On Jun 23, 2021, at 6:07 AM, Dan Carpenter wro= te: >=20 > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.gi= t master > head: 0c18f29aae7ce3dadd26d8ee3505d07cc982df75 > commit: e10fa96d347488d1fd278e84f52ba7b25067cc71 xprtrdma: Move cqe to st= ruct rpcrdma_mr > config: x86_64-randconfig-m001-20210622 (attached as .config) > compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 >=20 > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot > Reported-by: Dan Carpenter >=20 > New smatch warnings: > net/sunrpc/xprtrdma/frwr_ops.c:647 frwr_unmap_async() error: potentially = dereferencing uninitialized 'last'. >=20 > Old smatch warnings: > net/sunrpc/xprtrdma/frwr_ops.c:546 frwr_unmap_sync() error: potentially d= ereferencing uninitialized 'last'. >=20 > vim +/last +647 net/sunrpc/xprtrdma/frwr_ops.c >=20 > d8099feda4833b Chuck Lever 2019-06-19 608 void frwr_unmap_async(struct = rpcrdma_xprt *r_xprt, struct rpcrdma_req *req) > d8099feda4833b Chuck Lever 2019-06-19 609 { > d8099feda4833b Chuck Lever 2019-06-19 610 struct ib_send_wr *first, *l= ast, **prev; > 5ecef9c8436695 Chuck Lever 2020-11-09 611 struct rpcrdma_ep *ep =3D r_= xprt->rx_ep; > d8099feda4833b Chuck Lever 2019-06-19 612 struct rpcrdma_frwr *frwr; > d8099feda4833b Chuck Lever 2019-06-19 613 struct rpcrdma_mr *mr; > d8099feda4833b Chuck Lever 2019-06-19 614 int rc; > d8099feda4833b Chuck Lever 2019-06-19 615 =20 > d8099feda4833b Chuck Lever 2019-06-19 616 /* Chain the LOCAL_INV Work = Requests and post them with > d8099feda4833b Chuck Lever 2019-06-19 617 * a single ib_post_send() c= all. > d8099feda4833b Chuck Lever 2019-06-19 618 */ > d8099feda4833b Chuck Lever 2019-06-19 619 frwr =3D NULL; > d8099feda4833b Chuck Lever 2019-06-19 620 prev =3D &first; > 265a38d4611360 Chuck Lever 2019-08-19 621 while ((mr =3D rpcrdma_mr_po= p(&req->rl_registered))) { >=20 > Is it possible for the ->rl_registered list to be empty? The one and only call site for frwr_unmap_async() in in rpcrdma_reply_handl= er(): 1483 if (!list_empty(&req->rl_registered)) 1484 frwr_unmap_async(r_xprt, req); 1485 /* LocalInv completion will complete the RPC */ 1486 else 1487 kref_put(&req->rl_kref, rpcrdma_reply_done); > If not, then just ignore this email. I seem to recall smatch catching this problem before. Is there a way to annotate frwr_unmap_async() to calm smatch's nerves? > d8099feda4833b Chuck Lever 2019-06-19 622 =20 > d8099feda4833b Chuck Lever 2019-06-19 623 trace_xprtrdma_mr_localinv(= mr); > d8099feda4833b Chuck Lever 2019-06-19 624 r_xprt->rx_stats.local_inv_= needed++; > d8099feda4833b Chuck Lever 2019-06-19 625 =20 > d8099feda4833b Chuck Lever 2019-06-19 626 frwr =3D &mr->frwr; > d8099feda4833b Chuck Lever 2019-06-19 627 last =3D &frwr->fr_invwr; > d8099feda4833b Chuck Lever 2019-06-19 628 last->next =3D NULL; > e10fa96d347488 Chuck Lever 2021-04-19 629 last->wr_cqe =3D &mr->mr_cq= e; > d8099feda4833b Chuck Lever 2019-06-19 630 last->sg_list =3D NULL; > d8099feda4833b Chuck Lever 2019-06-19 631 last->num_sge =3D 0; > d8099feda4833b Chuck Lever 2019-06-19 632 last->opcode =3D IB_WR_LOCA= L_INV; > d8099feda4833b Chuck Lever 2019-06-19 633 last->send_flags =3D IB_SEN= D_SIGNALED; > d8099feda4833b Chuck Lever 2019-06-19 634 last->ex.invalidate_rkey = =3D mr->mr_handle; > d8099feda4833b Chuck Lever 2019-06-19 635 =20 > e10fa96d347488 Chuck Lever 2021-04-19 636 last->wr_cqe->done =3D frwr= _wc_localinv; > e10fa96d347488 Chuck Lever 2021-04-19 637 =20 > d8099feda4833b Chuck Lever 2019-06-19 638 *prev =3D last; > d8099feda4833b Chuck Lever 2019-06-19 639 prev =3D &last->next; > d8099feda4833b Chuck Lever 2019-06-19 640 } > d8099feda4833b Chuck Lever 2019-06-19 641 =20 > d8099feda4833b Chuck Lever 2019-06-19 642 /* Strong send queue orderin= g guarantees that when the > d8099feda4833b Chuck Lever 2019-06-19 643 * last WR in the chain comp= letes, all WRs in the chain > d8099feda4833b Chuck Lever 2019-06-19 644 * are complete. The last co= mpletion will wake up the > d8099feda4833b Chuck Lever 2019-06-19 645 * RPC waiter. > d8099feda4833b Chuck Lever 2019-06-19 646 */ > e10fa96d347488 Chuck Lever 2021-04-19 @647 last->wr_cqe->done =3D frwr_= wc_localinv_done; >=20 > --- > 0-DAY CI Kernel Test Service, Intel Corporation > https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org >=20 -- Chuck Lever