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authorMichael J. Ruhl <michael.j.ruhl@intel.com>2019-02-26 08:45:25 -0800
committerJason Gunthorpe <jgg@mellanox.com>2019-03-04 15:47:23 -0400
commitd757c60eca9b22f4d108929a24401e0fdecda0b1 (patch)
treee7b890d54e90e573ef6f3c0a27d621e57056d943
parent38bbc9f0381550d1d227fc57afa08436e36b32fc (diff)
IB/rdmavt: Fix concurrency panics in QP post_send and modify to error
The RC/UC code path can go through a software loopback. In this code path the receive side QP is manipulated. If two threads are working on the QP receive side (i.e. post_send, and modify_qp to an error state), QP information can be corrupted. (post_send via loopback) set r_sge loop update r_sge (modify_qp) take r_lock update r_sge <---- r_sge is now incorrect (post_send) update r_sge <---- crash, etc. ... This can lead to one of the two following crashes: BUG: unable to handle kernel NULL pointer dereference at (null) IP: hfi1_copy_sge+0xf1/0x2e0 [hfi1] PGD 8000001fe6a57067 PUD 1fd9e0c067 PMD 0 Call Trace: ruc_loopback+0x49b/0xbc0 [hfi1] hfi1_do_send+0x38e/0x3e0 [hfi1] _hfi1_do_send+0x1e/0x20 [hfi1] process_one_work+0x17f/0x440 worker_thread+0x126/0x3c0 kthread+0xd1/0xe0 ret_from_fork_nospec_begin+0x21/0x21 or: BUG: unable to handle kernel NULL pointer dereference at 0000000000000048 IP: rvt_clear_mr_refs+0x45/0x370 [rdmavt] PGD 80000006ae5eb067 PUD ef15d0067 PMD 0 Call Trace: rvt_error_qp+0xaa/0x240 [rdmavt] rvt_modify_qp+0x47f/0xaa0 [rdmavt] ib_security_modify_qp+0x8f/0x400 [ib_core] ib_modify_qp_with_udata+0x44/0x70 [ib_core] modify_qp.isra.23+0x1eb/0x2b0 [ib_uverbs] ib_uverbs_modify_qp+0xaa/0xf0 [ib_uverbs] ib_uverbs_write+0x272/0x430 [ib_uverbs] vfs_write+0xc0/0x1f0 SyS_write+0x7f/0xf0 system_call_fastpath+0x1c/0x21 Fix by using the appropriate locking on the receiving QP. Fixes: 15703461533a ("IB/{hfi1, qib, rdmavt}: Move ruc_loopback to rdmavt") Cc: <stable@vger.kernel.org> #v4.9+ Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
-rw-r--r--drivers/infiniband/sw/rdmavt/qp.c33
1 files changed, 23 insertions, 10 deletions
diff --git a/drivers/infiniband/sw/rdmavt/qp.c b/drivers/infiniband/sw/rdmavt/qp.c
index 337365806261..a34b9a2a32b6 100644
--- a/drivers/infiniband/sw/rdmavt/qp.c
+++ b/drivers/infiniband/sw/rdmavt/qp.c
@@ -2790,6 +2790,18 @@ again:
}
EXPORT_SYMBOL(rvt_copy_sge);
+static enum ib_wc_status loopback_qp_drop(struct rvt_ibport *rvp,
+ struct rvt_qp *sqp)
+{
+ rvp->n_pkt_drops++;
+ /*
+ * For RC, the requester would timeout and retry so
+ * shortcut the timeouts and just signal too many retries.
+ */
+ return sqp->ibqp.qp_type == IB_QPT_RC ?
+ IB_WC_RETRY_EXC_ERR : IB_WC_SUCCESS;
+}
+
/**
* ruc_loopback - handle UC and RC loopback requests
* @sqp: the sending QP
@@ -2862,17 +2874,14 @@ again:
}
spin_unlock_irqrestore(&sqp->s_lock, flags);
- if (!qp || !(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK) ||
+ if (!qp) {
+ send_status = loopback_qp_drop(rvp, sqp);
+ goto serr_no_r_lock;
+ }
+ spin_lock_irqsave(&qp->r_lock, flags);
+ if (!(ib_rvt_state_ops[qp->state] & RVT_PROCESS_RECV_OK) ||
qp->ibqp.qp_type != sqp->ibqp.qp_type) {
- rvp->n_pkt_drops++;
- /*
- * For RC, the requester would timeout and retry so
- * shortcut the timeouts and just signal too many retries.
- */
- if (sqp->ibqp.qp_type == IB_QPT_RC)
- send_status = IB_WC_RETRY_EXC_ERR;
- else
- send_status = IB_WC_SUCCESS;
+ send_status = loopback_qp_drop(rvp, sqp);
goto serr;
}
@@ -3030,6 +3039,7 @@ do_write:
wqe->wr.send_flags & IB_SEND_SOLICITED);
send_comp:
+ spin_unlock_irqrestore(&qp->r_lock, flags);
spin_lock_irqsave(&sqp->s_lock, flags);
rvp->n_loop_pkts++;
flush_send:
@@ -3056,6 +3066,7 @@ rnr_nak:
}
if (sqp->s_rnr_retry_cnt < 7)
sqp->s_rnr_retry--;
+ spin_unlock_irqrestore(&qp->r_lock, flags);
spin_lock_irqsave(&sqp->s_lock, flags);
if (!(ib_rvt_state_ops[sqp->state] & RVT_PROCESS_RECV_OK))
goto clr_busy;
@@ -3084,6 +3095,8 @@ err:
rvt_rc_error(qp, wc.status);
serr:
+ spin_unlock_irqrestore(&qp->r_lock, flags);
+serr_no_r_lock:
spin_lock_irqsave(&sqp->s_lock, flags);
rvt_send_complete(sqp, wqe, send_status);
if (sqp->ibqp.qp_type == IB_QPT_RC) {