dst: catch uninitialized metrics

[ Upstream commit 1f37070d3ff325827c6213e51b57f21fd5ac9d05 ]

Catch cases where dst_metric_set() and other functions are called
but _metrics is NULL.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/net/dst.h b/include/net/dst.h
index 75b95df4afe71467bb9d378f5535ab1e167772df..b3ad020faec52441d63c5a98407be2d6237643ff 100644 (file)
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -120,6 +120,8 @@ static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst)
 {
        unsigned long p = dst->_metrics;
 
+       BUG_ON(!p);
+
        if (p & DST_METRICS_READ_ONLY)
                return dst->ops->cow_metrics(dst, p);
        return __DST_METRICS_PTR(p);