releases/2.6.29.5/net-fix-length-computation-in-rt_check_expire.patch

   1 From a99a7b580bcb2d04a5d971f73fef790945ad458f Mon Sep 17 00:00:00 2001
   2 yyFrom: Eric Dumazet <dada1@cosmosbay.com>
   3 Date: Tue, 19 May 2009 18:54:22 +0000
   4 Subject: net: fix length computation in rt_check_expire()
   5
   6 From: Eric Dumazet <dada1@cosmosbay.com>
   7
   8 [ Upstream commit cf8da764fc6959b7efb482f375dfef9830e98205 ]
   9
  10 rt_check_expire() computes average and standard deviation of chain lengths,
  11 but not correclty reset length to 0 at beginning of each chain.
  12 This probably gives overflows for sum2 (and sum) on loaded machines instead
  13 of meaningful results.
  14
  15 Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
  16 Acked-by: Neil Horman <nhorman@tuxdriver.com>
  17 Signed-off-by: David S. Miller <davem@davemloft.net>
  18 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  19
  20 ---
  21  net/ipv4/route.c |    5 +++--
  22  1 file changed, 3 insertions(+), 2 deletions(-)
  23
  24 --- a/net/ipv4/route.c
  25 +++ b/net/ipv4/route.c
  26 @@ -785,7 +785,7 @@ static void rt_check_expire(void)
  27         static unsigned int rover;
  28         unsigned int i = rover, goal;
  29         struct rtable *rth, **rthp;
  30 -       unsigned long length = 0, samples = 0;
  31 +       unsigned long samples = 0;
  32         unsigned long sum = 0, sum2 = 0;
  33         u64 mult;
  34
  35 @@ -795,9 +795,9 @@ static void rt_check_expire(void)
  36         goal = (unsigned int)mult;
  37         if (goal > rt_hash_mask)
  38                 goal = rt_hash_mask + 1;
  39 -       length = 0;
  40         for (; goal > 0; goal--) {
  41                 unsigned long tmo = ip_rt_gc_timeout;
  42 +               unsigned long length;
  43
  44                 i = (i + 1) & rt_hash_mask;
  45                 rthp = &rt_hash_table[i].chain;
  46 @@ -809,6 +809,7 @@ static void rt_check_expire(void)
  47
  48                 if (*rthp == NULL)
  49                         continue;
  50 +               length = 0;
  51                 spin_lock_bh(rt_hash_lock_addr(i));
  52                 while ((rth = *rthp) != NULL) {
  53                         if (rt_is_expired(rth)) {