From: Eric Dumazet <edumazet@google.com>
Date: Sat, 25 Apr 2015 16:35:24 +0000 (-0700)
Subject: net: rfs: fix crash in get_rps_cpus()
X-Git-Tag: omap-for-v4.2/omap1-v2~58^2~7
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a31196b07f8034eba6a3487a1ad1bb5ec5cd58a5;p=pandora-kernel.git

net: rfs: fix crash in get_rps_cpus()

Commit 567e4b79731c ("net: rfs: add hash collision detection") had one
mistake :

RPS_NO_CPU is no longer the marker for invalid cpu in set_rps_cpu()
and get_rps_cpu(), as @next_cpu was the result of an AND with
rps_cpu_mask

This bug showed up on a host with 72 cpus :
next_cpu was 0x7f, and the code was trying to access percpu data of an
non existent cpu.

In a follow up patch, we might get rid of compares against nr_cpu_ids,
if we init the tables with 0. This is silly to test for a very unlikely
condition that exists only shortly after table initialization, as
we got rid of rps_reset_sock_flow() and similar functions that were
writing this RPS_NO_CPU magic value at flow dismantle : When table is
old enough, it never contains this value anymore.

Fixes: 567e4b79731c ("net: rfs: add hash collision detection")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Tom Herbert <tom@herbertland.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

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