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Subject[PATCH v2] RDMA/rxe: Prevent from double freeing rxe_map_set
Date
a same rxe_map_set could be freed twice:
rxe_reg_user_mr()
-> rxe_mr_init_user()
-> rxe_mr_free_map_set() # 1st
-> rxe_drop_ref()
...
-> rxe_mr_cleanup()
-> rxe_mr_free_map_set() # 2nd

By convention, we should cleanup/free resources in the error path in the
same function where the resources are alloted in. So rxe_mr_init_user()
doesn't need to free the map_set directly.

In addition, we have to reset map_set to NULL inside rxe_mr_alloc() if needed
to prevent from map_set being double freed in rxe_mr_cleanup().

CC: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
---
V2: Fix it by a simpler way by following suggestion from Bob,
---
drivers/infiniband/sw/rxe/rxe_mr.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index 25c78aade822..7c4cd19a9db2 100644
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -141,6 +141,7 @@ static int rxe_mr_alloc(struct rxe_mr *mr, int num_buf, int both)
ret = rxe_mr_alloc_map_set(num_map, &mr->next_map_set);
if (ret) {
rxe_mr_free_map_set(mr->num_map, mr->cur_map_set);
+ mr->cur_map_set = NULL;
goto err_out;
}
}
@@ -214,7 +215,7 @@ int rxe_mr_init_user(struct rxe_pd *pd, u64 start, u64 length, u64 iova,
pr_warn("%s: Unable to get virtual address\n",
__func__);
err = -ENOMEM;
- goto err_cleanup_map;
+ goto err_release_umem;
}

buf->addr = (uintptr_t)vaddr;
@@ -237,8 +238,6 @@ int rxe_mr_init_user(struct rxe_pd *pd, u64 start, u64 length, u64 iova,

return 0;

-err_cleanup_map:
- rxe_mr_free_map_set(mr->num_map, mr->cur_map_set);
err_release_umem:
ib_umem_release(umem);
err_out:
--
2.31.1


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