[NET]: Corrects a bug in ip_rt_acct_read()

It seems that stats of cpu 0 are counted twice, since
for_each_possible_cpu() is looping on all possible cpus, including 0

Before percpu conversion of ip_rt_acct, we should also remove the
assumption that CPU 0 is online (or even possible)

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 6 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 1bff9ed349ff..c426dec6d579 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2888,18 +2888,14 @@ static int ip_rt_acct_read(char *buffer, char **start, off_t offset,
         offset /= sizeof(u32);
 
         if (length > 0) {
-                u32 *src = ((u32 *) IP_RT_ACCT_CPU(0)) + offset;
                 u32 *dst = (u32 *) buffer;
 
-                /* Copy first cpu. */
                 *start = buffer;
-                memcpy(dst, src, length);
+                memset(dst, 0, length);
 
-                /* Add the other cpus in, one int at a time */
                 for_each_possible_cpu(i) {
                         unsigned int j;
-
-                        src = ((u32 *) IP_RT_ACCT_CPU(i)) + offset;
+                        u32 *src = ((u32 *) IP_RT_ACCT_CPU(i)) + offset;
 
                         for (j = 0; j < length/4; j++)
                                 dst[j] += src[j];