Messages in this thread | | | Date | Tue, 22 Nov 2011 20:32:31 +0100 | From | Markus Trippelsdorf <> | Subject | Re: slub: Lockout validation scans during freeing of object |
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On 2011.11.22 at 13:20 -0600, Christoph Lameter wrote: > On Tue, 22 Nov 2011, Markus Trippelsdorf wrote: > > > On 2011.11.22 at 11:40 -0600, Christoph Lameter wrote: > > > On Tue, 22 Nov 2011, Eric Dumazet wrote: > > > > > > > This seems better, but I still have some warnings : > > > > > > Trying to reproduce with a kernel configured to do preempt. This is > > > actually quite interesting since its always off by 1. > > > > BTW there are some obvious overflows in the "slabinfo -l" output on my machine: > > Could you get me the value of the "slabs" field for the slabs showing the > wierd values. I.e. do > > cat /sys/kernel/slab/signal_cache/slabs > > > signal_cache 268 920 360.4K 18446744073709551614/7/24 17 2 31 68 A >
It's quite easy to explain. You're using unsigned ints in: snprintf(dist_str, 40, "%lu/%lu/%d", s->slabs - s->cpu_slabs, s->partial, s->cpu_slabs);
and (s->slabs - s->cpu_slabs) can get negative. For example:
task_struct 269 1504 557.0K 18446744073709551601/5/32 21 3 29 72
Here s-slabs is 17 and s->cpu_slabs is 32. That gives: 17-32=18446744073709551601.
-- Markus
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