[PATCH] bpf: decrease usercnt if bpf_map_new_fd() fails in bpf_map_get_fd_by_id()

[zerons]

[ Upstream commit c91951f15978f1a0c6b65f063d30f7ea7bc6fb42 ]

In bpf/syscall.c, bpf_map_get_fd_by_id() use bpf_map_inc_not_zero() to increase
the refcount, both map->refcnt and map->usercnt. Then, if bpf_map_new_fd() 
fails,
should handle map->usercnt too.

Signed-off-by: zerons <sironhide0n...@gmail.com>
---
 kernel/bpf/syscall.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index cf5040f..db1ed12 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1966,7 +1966,7 @@ static int bpf_map_get_fd_by_id(const union bpf_attr 
*attr)

        fd = bpf_map_new_fd(map, f_flags);
        if (fd < 0)
-               bpf_map_put(map);
+               bpf_map_put_with_uref(map);

        return fd;
 }
--
2.7.4