From e214a0fe2b382fa302c036ecd6e6ffe99e3b9875 Mon Sep 17 00:00:00 2001 From: Eli Cohen 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 Signed-off-by: Eli Cohen Cc: Signed-off-by: Roland Dreier --- 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 254f1649c73..e3db8ef4fe4 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; } -- cgit v1.2.3-70-g09d2