From 4c8011e77c27b6a0ebb35406de7748660818e32a Mon Sep 17 00:00:00 2001 From: Felix Riemann Date: Fri, 10 Feb 2023 13:36:44 +0100 Subject: [PATCH] net: Fix unwanted sign extension in netdev_stats_to_stats64() commit 9b55d3f0a69af649c62cbc2633e6d695bb3cc583 upstream. When converting net_device_stats to rtnl_link_stats64 sign extension is triggered on ILP32 machines as 6c1c509778 changed the previous "ulong -> u64" conversion to "long -> u64" by accessing the net_device_stats fields through a (signed) atomic_long_t. This causes for example the received bytes counter to jump to 16EiB after having received 2^31 bytes. Casting the atomic value to "unsigned long" beforehand converting it into u64 avoids this. Fixes: 6c1c5097781f ("net: add atomic_long_t to net_device_stats fields") Signed-off-by: Felix Riemann Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/dev.c b/net/core/dev.c index 296bed9431f3..615cdaac3e72 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9467,7 +9467,7 @@ void netdev_stats_to_stats64(struct rtnl_link_stats64 *stats64, BUILD_BUG_ON(n > sizeof(*stats64) / sizeof(u64)); for (i = 0; i < n; i++) - dst[i] = atomic_long_read(&src[i]); + dst[i] = (unsigned long)atomic_long_read(&src[i]); /* zero out counters that only exist in rtnl_link_stats64 */ memset((char *)stats64 + n * sizeof(u64), 0, sizeof(*stats64) - n * sizeof(u64));