RE: [EXT] Re: drivers/infiniband/hw/qedr/verbs.c:1925 qedr_create_user_qp() error: we previously assumed 'ctx' could be null (see line 1900)

From: Michal Kalderon
Date: Thu Feb 18 2021 - 09:49:12 EST

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In reply to: Jason Gunthorpe: "Re: drivers/infiniband/hw/qedr/verbs.c:1925 qedr_create_user_qp() error: we previously assumed 'ctx' could be null (see line 1900)"
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> From: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Sent: Tuesday, February 16, 2021 9:03 PM
>
> ----------------------------------------------------------------------
> On Mon, Feb 15, 2021 at 04:31:25PM +0300, Dan Carpenter wrote:
> > tree: https://urldefense.proofpoint.com/v2/url?u=https-
> 3A__git.kernel.org_pub_scm_linux_kernel_git_torvalds_linux.git&d=DwIBA
> g&c=nKjWec2b6R0mOyPaz7xtfQ&r=5_8rRZTDuAS-6X-
> cGRU9Fo4yjCnkS1t7T3-gjL4FQng&m=YhK42aIA63YEc6ZxxEMSWb1_-
> N4zC52vzPRN82lyUa8&s=ZwYelPnxs3xwj988Lf0pr8AJK-
> oWmLXMQyGqlv74dtI&e= master
> > head: dcc0b49040c70ad827a7f3d58a21b01fdb14e749
> > commit: 06e8d1df46ed52eca6915a2a76341ca65cc428b9 RDMA/qedr: Add
> > support for user mode XRC-SRQ's
> > config: x86_64-randconfig-m001-20210213 (attached as .config)
> > compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> >
> > smatch warnings:
> > drivers/infiniband/hw/qedr/verbs.c:1925 qedr_create_user_qp() error:
> > we previously assumed 'ctx' could be null (see line 1900)
> >
> > vim +/ctx +1925 drivers/infiniband/hw/qedr/verbs.c
> >
> > df15856132bc83 Amrani, Ram 2016-12-22 1830 static int
> qedr_create_user_qp(struct qedr_dev *dev,
> > cecbcddf6461a1 Ram Amrani 2016-10-10 1831
> struct qedr_qp *qp,
> > df15856132bc83 Amrani, Ram 2016-12-22 1832
> struct ib_pd *ibpd,
> > df15856132bc83 Amrani, Ram 2016-12-22 1833
> struct ib_udata *udata,
> > df15856132bc83 Amrani, Ram 2016-12-22 1834
> struct ib_qp_init_attr *attrs)
> > cecbcddf6461a1 Ram Amrani 2016-10-10 1835 {
> > df15856132bc83 Amrani, Ram 2016-12-22 1836 struct
> qed_rdma_create_qp_in_params in_params;
> > df15856132bc83 Amrani, Ram 2016-12-22 1837 struct
> qed_rdma_create_qp_out_params out_params;
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1838 struct
> qedr_create_qp_uresp uresp = {};
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1839 struct
> qedr_create_qp_ureq ureq = {};
> > 69ad0e7fe8452a Kalderon, Michal 2017-07-26 1840 int alloc_and_init =
> rdma_protocol_roce(&dev->ibdev, 1);
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1841 struct qedr_ucontext
> *ctx = NULL;
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1842 struct qedr_pd *pd =
> NULL;
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1843 int rc = 0;
> > cecbcddf6461a1 Ram Amrani 2016-10-10 1844
> > 82af6d19d8d922 Michal Kalderon 2019-10-27 1845 qp->create_type =
> QEDR_QP_CREATE_USER;
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1846
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1847 if (ibpd) {
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1848 pd =
> get_qedr_pd(ibpd);
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1849 ctx = pd-
> >uctx;
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1850 }
> >
> > "ctx" is NULL on the else path.
>
> Looks like ibpd can never be NULL, so this is dead code
>
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1851
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1852 if (udata) {
>
> udata also can never be null because this is called 'qedr_create_user_qp' ?
>
> It is confusingly called with a xrcd test too, but xrcd's are only currently
> possible if udata is set.
>
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1853 rc =
> ib_copy_from_udata(&ureq, udata, min(sizeof(ureq),
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1854
> udata->inlen));
> > df15856132bc83 Amrani, Ram 2016-12-22 1855 if (rc) {
> > df15856132bc83 Amrani, Ram 2016-12-22 1856
> DP_ERR(dev, "Problem copying data from user space\n");
> > df15856132bc83 Amrani, Ram 2016-12-22 1857
> return rc;
> > df15856132bc83 Amrani, Ram 2016-12-22 1858 }
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1859 }
> > cecbcddf6461a1 Ram Amrani 2016-10-10 1860
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1861 if
> (qedr_qp_has_sq(qp)) {
> > 72b894b09a96b7 Christoph Hellwig 2019-11-13 1862 /* SQ - read
> access only (0) */
> > b0ea0fa5435f9d Jason Gunthorpe 2019-01-09 1863 rc =
> qedr_init_user_queue(udata, dev, &qp->usq, ureq.sq_addr,
> > 72b894b09a96b7 Christoph Hellwig 2019-11-13 1864
> ureq.sq_len, true, 0, alloc_and_init);
> > df15856132bc83 Amrani, Ram 2016-12-22 1865 if (rc)
> > df15856132bc83 Amrani, Ram 2016-12-22 1866
> return rc;
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1867 }
> > cecbcddf6461a1 Ram Amrani 2016-10-10 1868
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1869 if
> (qedr_qp_has_rq(qp)) {
> > 72b894b09a96b7 Christoph Hellwig 2019-11-13 1870 /* RQ - read
> access only (0) */
> > b0ea0fa5435f9d Jason Gunthorpe 2019-01-09 1871 rc =
> qedr_init_user_queue(udata, dev, &qp->urq, ureq.rq_addr,
> > 72b894b09a96b7 Christoph Hellwig 2019-11-13 1872
> ureq.rq_len, true, 0, alloc_and_init);
> > df15856132bc83 Amrani, Ram 2016-12-22 1873 if (rc)
> > df15856132bc83 Amrani, Ram 2016-12-22 1874
> return rc;
> > 40b173ddce0fc6 Yuval Bason 2018-08-09 1875 }
> > df15856132bc83 Amrani, Ram 2016-12-22 1876
> > df15856132bc83 Amrani, Ram 2016-12-22 1877 memset(&in_params,
> 0, sizeof(in_params));
> > df15856132bc83 Amrani, Ram 2016-12-22 1878
> qedr_init_common_qp_in_params(dev, pd, qp, attrs, false,
> &in_params);
> > df15856132bc83 Amrani, Ram 2016-12-22 1879
> in_params.qp_handle_lo = ureq.qp_handle_lo;
> > df15856132bc83 Amrani, Ram 2016-12-22 1880
> in_params.qp_handle_hi = ureq.qp_handle_hi;
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1881
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1882 if (qp->qp_type ==
> IB_QPT_XRC_TGT) {
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1883 struct
> qedr_xrcd *xrcd = get_qedr_xrcd(attrs->xrcd);
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1884
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1885
> in_params.xrcd_id = xrcd->xrcd_id;
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1886
> in_params.qp_handle_lo = qp->qp_id;
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1887
> in_params.use_srq = 1;
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1888 }
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1889
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1890 if
> (qedr_qp_has_sq(qp)) {
> > df15856132bc83 Amrani, Ram 2016-12-22 1891
> in_params.sq_num_pages = qp->usq.pbl_info.num_pbes;
> > df15856132bc83 Amrani, Ram 2016-12-22 1892
> in_params.sq_pbl_ptr = qp->usq.pbl_tbl->pa;
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1893 }
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1894
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1895 if
> (qedr_qp_has_rq(qp)) {
> > df15856132bc83 Amrani, Ram 2016-12-22 1896
> in_params.rq_num_pages = qp->urq.pbl_info.num_pbes;
> > df15856132bc83 Amrani, Ram 2016-12-22 1897
> in_params.rq_pbl_ptr = qp->urq.pbl_tbl->pa;
> > 40b173ddce0fc6 Yuval Bason 2018-08-09 1898 }
> > df15856132bc83 Amrani, Ram 2016-12-22 1899
> > bbe4f4245271bd Michal Kalderon 2020-07-07 @1900 if (ctx)
> > ^^^ Check
> > for NULL
> >
> > bbe4f4245271bd Michal Kalderon 2020-07-07 1901
> SET_FIELD(in_params.flags, QED_ROCE_EDPM_MODE, ctx-
> >edpm_mode);
> > bbe4f4245271bd Michal Kalderon 2020-07-07 1902
> > df15856132bc83 Amrani, Ram 2016-12-22 1903 qp->qed_qp = dev-
> >ops->rdma_create_qp(dev->rdma_ctx,
> > df15856132bc83 Amrani, Ram 2016-12-22 1904
> &in_params, &out_params);
> > df15856132bc83 Amrani, Ram 2016-12-22 1905
> > df15856132bc83 Amrani, Ram 2016-12-22 1906 if (!qp->qed_qp) {
> > df15856132bc83 Amrani, Ram 2016-12-22 1907 rc = -
> ENOMEM;
> > df15856132bc83 Amrani, Ram 2016-12-22 1908 goto err1;
> > df15856132bc83 Amrani, Ram 2016-12-22 1909 }
> > df15856132bc83 Amrani, Ram 2016-12-22 1910
> > 69ad0e7fe8452a Kalderon, Michal 2017-07-26 1911 if
> (rdma_protocol_iwarp(&dev->ibdev, 1))
> > 69ad0e7fe8452a Kalderon, Michal 2017-07-26 1912
> qedr_iwarp_populate_user_qp(dev, qp, &out_params);
> > 69ad0e7fe8452a Kalderon, Michal 2017-07-26 1913
> > df15856132bc83 Amrani, Ram 2016-12-22 1914 qp->qp_id =
> out_params.qp_id;
> > df15856132bc83 Amrani, Ram 2016-12-22 1915 qp->icid =
> out_params.icid;
> > df15856132bc83 Amrani, Ram 2016-12-22 1916
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1917 if (udata) {
> > 97f612509294aa Michal Kalderon 2019-10-30 1918 rc =
> qedr_copy_qp_uresp(dev, qp, udata, &uresp);
> > 97f612509294aa Michal Kalderon 2019-10-30 1919 if (rc)
> > 97f612509294aa Michal Kalderon 2019-10-30 1920 goto
> err;
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1921 }
> > 97f612509294aa Michal Kalderon 2019-10-30 1922
> > 97f612509294aa Michal Kalderon 2019-10-30 1923 /* db offset was
> calculated in copy_qp_uresp, now set in the user q */
> > 06e8d1df46ed52 Yuval Basson 2020-07-22 1924 if
> (qedr_qp_has_sq(qp)) {
> > 97f612509294aa Michal Kalderon 2019-10-30 @1925 qp-
> >usq.db_addr = ctx->dpi_addr + uresp.sq_db_offset;
> >
> > ^^^^^^^^^^^^^ Can "ctx" be NULL here?
>
> This would also not work right if udata == NULL
>
> Whole function needs cleaning, but doesn't look buggy
>
Thanks, agreed, and will take care of the function re-write.

> Jason

Next message: Michael Walle: "Re: [PATCH 2/2] arm64: dts: fsl: add support for Kontron pitx-imx8m board"
Previous message: Paolo Bonzini: "Re: [PATCH 08/14] KVM: x86/mmu: Make dirty log size hook (PML) a value, not a function"
In reply to: Jason Gunthorpe: "Re: drivers/infiniband/hw/qedr/verbs.c:1925 qedr_create_user_qp() error: we previously assumed 'ctx' could be null (see line 1900)"
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