From e214a0fe2b382fa302c036ecd6e6ffe99e3b9875 Mon Sep 17 00:00:00 2001
From: Eli Cohen <eli@dev.mellanox.co.il>
Date: Tue, 3 Jan 2012 20:36:48 -0800
Subject: IB/uverbs: Protect QP multicast list
Userspace verbs multicast attach/detach operations on a QP are done
while holding the rwsem of the QP for reading. That's not sufficient
since a reader lock allows more than one reader to acquire the
lock. However, multicast attach/detach does list manipulation that
can corrupt the list if multiple threads run in parallel.
Fix this by acquiring the rwsem as a writer to serialize attach/detach
operations. Add idr_write_qp() and put_qp_write() to encapsulate
this.
This fixes oops seen when running applications that perform multicast
joins/leaves.
Reported by: Mike Dubman <miked@mellanox.com>
Signed-off-by: Eli Cohen <eli@mellanox.com>
Cc: <stable@kernel.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>
---
drivers/infiniband/core/uverbs_cmd.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
(limited to 'drivers/infiniband')
diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 254f1649c734..e3db8ef4fe4e 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -241,11 +241,24 @@ static struct ib_qp *idr_read_qp(int qp_handle, struct ib_ucontext *context)
return idr_read_obj(&ib_uverbs_qp_idr, qp_handle, context, 0);
}
+static struct ib_qp *idr_write_qp(int qp_handle, struct ib_ucontext *context)
+{
+ struct ib_uobject *uobj;
+
+ uobj = idr_write_uobj(&ib_uverbs_qp_idr, qp_handle, context);
+ return uobj ? uobj->object : NULL;
+}
+
static void put_qp_read(struct ib_qp *qp)
{
put_uobj_read(qp->uobject);
}
+static void put_qp_write(struct ib_qp *qp)
+{
+ put_uobj_write(qp->uobject);
+}
+
static struct ib_srq *idr_read_srq(int srq_handle, struct ib_ucontext *context)
{
return idr_read_obj(&ib_uverbs_srq_idr, srq_handle, context, 0);
@@ -2375,7 +2388,7 @@ ssize_t ib_uverbs_attach_mcast(struct ib_uverbs_file *file,
if (copy_from_user(&cmd, buf, sizeof cmd))
return -EFAULT;
- qp = idr_read_qp(cmd.qp_handle, file->ucontext);
+ qp = idr_write_qp(cmd.qp_handle, file->ucontext);
if (!qp)
return -EINVAL;
@@ -2404,7 +2417,7 @@ ssize_t ib_uverbs_attach_mcast(struct ib_uverbs_file *file,
kfree(mcast);
out_put:
- put_qp_read(qp);
+ put_qp_write(qp);
return ret ? ret : in_len;
}
@@ -2422,7 +2435,7 @@ ssize_t ib_uverbs_detach_mcast(struct ib_uverbs_file *file,
if (copy_from_user(&cmd, buf, sizeof cmd))
return -EFAULT;
- qp = idr_read_qp(cmd.qp_handle, file->ucontext);
+ qp = idr_write_qp(cmd.qp_handle, file->ucontext);
if (!qp)
return -EINVAL;
@@ -2441,7 +2454,7 @@ ssize_t ib_uverbs_detach_mcast(struct ib_uverbs_file *file,
}
out_put:
- put_qp_read(qp);
+ put_qp_write(qp);
return ret ? ret : in_len;
}
--
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