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author | Liu Yu <allanyuliu@tencent.com> | 2014-04-30 13:34:09 +0400 |
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committer | Jiri Slaby <jslaby@suse.cz> | 2014-05-29 13:49:26 +0400 |
commit | e78282a5759165273c4a704c842dc808e85b1780 (patch) | |
tree | 183d312ec66d58106607793da89fb8045e773b1e /include/net | |
parent | 04adf0fb0c5a2d52279ff6a2215dad9187bc9890 (diff) | |
download | linux-e78282a5759165273c4a704c842dc808e85b1780.tar.xz |
tcp_cubic: fix the range of delayed_ack
[ Upstream commit 0cda345d1b2201dd15591b163e3c92bad5191745 ]
commit b9f47a3aaeab (tcp_cubic: limit delayed_ack ratio to prevent
divide error) try to prevent divide error, but there is still a little
chance that delayed_ack can reach zero. In case the param cnt get
negative value, then ratio+cnt would overflow and may happen to be zero.
As a result, min(ratio, ACK_RATIO_LIMIT) will calculate to be zero.
In some old kernels, such as 2.6.32, there is a bug that would
pass negative param, which then ultimately leads to this divide error.
commit 5b35e1e6e9c (tcp: fix tcp_trim_head() to adjust segment count
with skb MSS) fixed the negative param issue. However,
it's safe that we fix the range of delayed_ack as well,
to make sure we do not hit a divide by zero.
CC: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Liu Yu <allanyuliu@tencent.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'include/net')
0 files changed, 0 insertions, 0 deletions