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IB/uverbs: Fix unbalanced unlock on error path for rdma_explicit_destroy

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If remove_commit fails then the lock is left locked while the uobj still
exists. Eventually the kernel will deadlock.

lockdep detects this and says:

 test/4221 is leaving the kernel with locks still held!
 1 lock held by test/4221:
  #0:  (&ucontext->cleanup_rwsem){.+.+}, at: [<000000001e5c7523>] rdma_explicit_destroy+0x37/0x120 [ib_uverbs]

Fixes: 4da70da23e ("IB/core: Explicitly destroy an object while keeping uobject")
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Jason Gunthorpe 2018-02-13 12:18:40 +02:00
parent 104f268d43
commit ec6f8401c4
1 changed files with 3 additions and 2 deletions
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5
drivers/infiniband/core/rdma_core.c
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@ -491,12 +491,13 @@ int rdma_explicit_destroy(struct ib_uobject *uobject)
ret = uobject->type->type_class->remove_commit(uobject,
RDMA_REMOVE_DESTROY);
if (ret)
return ret;
goto out;
uobject->type = &null_obj_type;
out:
up_read(&ucontext->cleanup_rwsem);
return 0;
return ret;
}
static void alloc_commit_idr_uobject(struct ib_uobject *uobj)