Re: null pointer in rxe_mr_copy()

[Zhu Yanjun <zyjzyj2000@gmail.com>]

On Mon, Apr 11, 2022 at 1:14 PM Zhu Yanjun <zyjzyj2000@gmail.com> wrote:
>
> On Mon, Apr 11, 2022 at 11:34 AM Bob Pearson <rpearsonhpe@gmail.com> wrote:
> >
> > Zhu,
> >
> > Since checking for mr == NULL in rxe_mr_copy fixes the problem you were seeing in rping.
> > Perhaps it would be a good idea to apply the following patch which would tell us which of
> > the three calls to rxe_mr_copy is failing. My suspicion is the one in read_reply()
> Hi, Bob
>
> Yes. It is the function read_reply.

 720 static enum resp_states read_reply(struct rxe_qp *qp,
 721                                    struct rxe_pkt_info *req_pkt)
 722 {
 723         struct rxe_pkt_info ack_pkt;
 724         struct sk_buff *skb;
 725         int mtu = qp->mtu;
 726         enum resp_states state;
 727         int payload;
 728         int opcode;
 729         int err;
 730         struct resp_res *res = qp->resp.res;
 731         struct rxe_mr *mr;
 732
 733         if (!res) {
 734                 res = rxe_prepare_read_res(qp, req_pkt);
 735                 qp->resp.res = res;
 736         }
 737
 738         if (res->state == rdatm_res_state_new) {
 739                 mr = qp->resp.mr;
<----It seems that mr is from here.
 740                 qp->resp.mr = NULL;
 741


>
>  kernel: ------------[ cut here ]------------
>  kernel: WARNING: CPU: 74 PID: 38510 at
> drivers/infiniband/sw/rxe/rxe_resp.c:768 rxe_responder+0x1d67/0x1dd0
> [rdma_rxe]
>  kernel: Modules linked in: rdma_rxe(OE) ip6_udp_tunnel udp_tunnel
> rds_rdma rds xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT
> nf_reject_ipv4 nft_compat nft_chain_nat nf_nat nf_conntrack
> nf_defrag_ipv6 nf_defrag_ipv4 nf_tables nfnetlink tun bridge stp llc
> vfat fat rpcrdma sunrpc rdma_ucm ib_srpt ib_isert iscsi_target_mod
> target_core_mod intel_rapl_msr intel_rapl_common ib_iser libiscsi
> scsi_transport_iscsi rdma_cm ib_cm i10nm_edac iw_cm nfit libnvdimm
> x86_pkg_temp_thermal intel_powerclamp coretemp ipmi_ssif kvm_intel kvm
> irdma iTCO_wdt iTCO_vendor_support i40e irqbypass crct10dif_pclmul
> crc32_pclmul ib_uverbs ghash_clmulni_intel rapl intel_cstate ib_core
> intel_uncore wmi_bmof pcspkr mei_me isst_if_mbox_pci isst_if_mmio
> acpi_ipmi isst_if_common ipmi_si i2c_i801 mei intel_pch_thermal
> i2c_smbus ipmi_devintf ipmi_msghandler acpi_power_meter ip_tables xfs
> libcrc32c sd_mod t10_pi crc64_rocksoft crc64 sg mgag200 i2c_algo_bit
> drm_shmem_helper drm_kms_helper syscopyarea sysfillrect ice
>  kernel: sysimgblt fb_sys_fops ahci drm libahci crc32c_intel libata
> megaraid_sas tg3 wmi dm_mirror dm_region_hash dm_log dm_mod fuse [last
> unloaded: ip6_udp_tunnel]
>  kernel: CPU: 74 PID: 38510 Comm: rping Kdump: loaded Tainted: G S
>  W  OE     5.18.0.RXE #14
>  kernel: Hardware name: Dell Inc. PowerEdge R750/06V45N, BIOS 1.2.4 05/28/2021
>  kernel: RIP: 0010:rxe_responder+0x1d67/0x1dd0 [rdma_rxe]
>  kernel: Code: 24 30 48 89 44 24 30 49 8b 86 88 00 00 00 48 89 44 24
> 38 48 8b 73 20 48 8b 43 18 ff d0 0f 1f 00 e9 10 e3 ff ff e8 e9 52 98
> ee <0f> 0b 45 8b 86 f0 00 00 00 48 8b 8c 24 e0 00 00 00 ba 01 03 00 00
>  kernel: RSP: 0018:ff5f5b78c7624e70 EFLAGS: 00010246
>  kernel: RAX: ff20346c70a1d700 RBX: ff20346c7127c040 RCX: ff20346c70a1d700
>  kernel: RDX: 0000000000000000 RSI: 0000000000000000 RDI: ff20346c53194000
>  kernel: RBP: 0000000000000040 R08: 2ebbb556a556fe7f R09: 69de575d0320dc48
>  kernel: R10: ff5f5b78c7624de0 R11: 00000000ee4984a4 R12: ff20346c70a1d700
>  kernel: R13: 0000000000000000 R14: ff20346ef0539000 R15: ff20346c70a1c528
>  kernel: FS:  00007ff34d49b740(0000) GS:ff20347b3fa80000(0000)
> knlGS:0000000000000000
>  kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>  kernel: CR2: 00007ff40be030c0 CR3: 00000003d0634005 CR4: 0000000000771ee0
>  kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>  kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>  kernel: PKRU: 55555554
>  kernel: Call Trace:
>  kernel: <IRQ>
>  kernel: ? __local_bh_enable_ip+0x9f/0xe0
>  kernel: ? rxe_do_task+0x67/0xe0 [rdma_rxe]
>  kernel: ? __local_bh_enable_ip+0x77/0xe0
>  kernel: rxe_do_task+0x71/0xe0 [rdma_rxe]
>  kernel: tasklet_action_common.isra.15+0xb8/0xf0
>  kernel: __do_softirq+0xe4/0x48c
>  kernel: ? rxe_do_task+0x67/0xe0 [rdma_rxe]
>  kernel: do_softirq+0xb5/0x100
>  kernel: </IRQ>
>  kernel: <TASK>
>  kernel: __local_bh_enable_ip+0xd0/0xe0
>  kernel: rxe_do_task+0x67/0xe0 [rdma_rxe]
>  kernel: rxe_post_send+0x2ff/0x4c0 [rdma_rxe]
>  kernel: ? rdma_lookup_get_uobject+0x131/0x1e0 [ib_uverbs]
>  kernel: ib_uverbs_post_send+0x4d5/0x700 [ib_uverbs]
>  kernel: ib_uverbs_write+0x38f/0x5e0 [ib_uverbs]
>  kernel: ? find_held_lock+0x2d/0x90
>  kernel: vfs_write+0xb8/0x370
>  kernel: ksys_write+0xbb/0xd0
>  kernel: ? syscall_trace_enter.isra.15+0x169/0x220
>  kernel: do_syscall_64+0x37/0x80
>
> Zhu Yanjun
>
>  in rxe_resp.c
> > This could be caused by a race between shutting down the qp and finishing up an RDMA read.
> > The responder resources state machine is completely unprotected from simultaneous access by
> > verbs code and bh code in rxe_resp.c. rxe_resp is a tasklet so all the accesses from there are
> > serialized but if anyone makes a verbs call that touches the responder resources it could
> > cause problems. The most likely (only?) place this could happen is qp shutdown.
> >
> > Bob
> >
> >
> >
> > diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
> >
> > index 60a31b718774..66184f5a4ddf 100644
> >
> > --- a/drivers/infiniband/sw/rxe/rxe_mr.c
> >
> > +++ b/drivers/infiniband/sw/rxe/rxe_mr.c
> >
> > @@ -489,6 +489,7 @@ int copy_data(
> >
> >                 if (bytes > 0) {
> >
> >                         iova = sge->addr + offset;
> >
> >
> >
> > +                       WARN_ON(!mr);
> >
> >                         err = rxe_mr_copy(mr, iova, addr, bytes, dir);
> >
> >                         if (err)
> >
> >                                 goto err2;
> >
> > diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
> >
> > index 1d95fab606da..6e3e86bdccd7 100644
> >
> > --- a/drivers/infiniband/sw/rxe/rxe_resp.c
> >
> > +++ b/drivers/infiniband/sw/rxe/rxe_resp.c
> >
> > @@ -536,6 +536,7 @@ static enum resp_states write_data_in(struct rxe_qp *qp,
> >
> >         int     err;
> >
> >         int data_len = payload_size(pkt);
> >
> >
> >
> > +       WARN_ON(!qp->resp.mr);
> >
> >         err = rxe_mr_copy(qp->resp.mr, qp->resp.va + qp->resp.offset,
> >
> >                           payload_addr(pkt), data_len, RXE_TO_MR_OBJ);
> >
> >         if (err) {
> >
> > @@ -772,6 +773,7 @@ static enum resp_states read_reply(struct rxe_qp *qp,
> >
> >         if (!skb)
> >
> >                 return RESPST_ERR_RNR;
> >
> >
> >
> > +       WARN_ON(!mr);
> >
> >         err = rxe_mr_copy(mr, res->read.va, payload_addr(&ack_pkt),
> >
> >                           payload, RXE_FROM_MR_OBJ);
> >
> >         if (err)
> >