diff options
| author | Eric Dumazet <edumazet@google.com> | 2015-04-25 09:35:24 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-05-06 22:03:35 +0200 |
| commit | b32dec8a9f5834b14daaa75bd3e49f3b54272d65 (patch) | |
| tree | 144946a64f3f83f80e5a084349cb7d2ba2c8fc2d /Documentation | |
| parent | f80e3eb94b7d4b5b9ebf999da1f50cd5b263a23d (diff) | |
net: rfs: fix crash in get_rps_cpus()
[ Upstream commit a31196b07f8034eba6a3487a1ad1bb5ec5cd58a5 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/networking/scaling.txt | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/Documentation/networking/scaling.txt b/Documentation/networking/scaling.txt index 99ca40e8e810..5c204df6b689 100644 --- a/Documentation/networking/scaling.txt +++ b/Documentation/networking/scaling.txt @@ -282,7 +282,7 @@ following is true: - The current CPU's queue head counter >= the recorded tail counter value in rps_dev_flow[i] -- The current CPU is unset (equal to RPS_NO_CPU) +- The current CPU is unset (>= nr_cpu_ids) - The current CPU is offline After this check, the packet is sent to the (possibly updated) current |