Messages in this thread Patch in this message | | | Date | Tue, 29 Sep 2009 01:19:13 +0900 | From | Tejun Heo <> | Subject | [PATCH] percpu: fix unit_map[] verification in pcpu_setup_first_chunk() |
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pcpu_setup_first_chunk() incorrectly used NR_CPUS as the impossible unit number while unit number can equal and go over NR_CPUS with sparse unit map. This triggers BUG_ON() spuriously on machines which have non-power-of-two number of cpus. Use UINT_MAX instead.
Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Tony Vroon <tony@linx.net> --- Erghh... stupid mistake. This should fix it. Can you please verify?
Thanks.
mm/percpu.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
Index: work/mm/percpu.c =================================================================== --- work.orig/mm/percpu.c +++ work/mm/percpu.c @@ -1604,7 +1604,7 @@ int __init pcpu_setup_first_chunk(const unit_off = alloc_bootmem(nr_cpu_ids * sizeof(unit_off[0]));
for (cpu = 0; cpu < nr_cpu_ids; cpu++) - unit_map[cpu] = NR_CPUS; + unit_map[cpu] = UINT_MAX; pcpu_first_unit_cpu = NR_CPUS;
for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) { @@ -1619,7 +1619,7 @@ int __init pcpu_setup_first_chunk(const continue;
BUG_ON(cpu > nr_cpu_ids || !cpu_possible(cpu)); - BUG_ON(unit_map[cpu] != NR_CPUS); + BUG_ON(unit_map[cpu] != UINT_MAX);
unit_map[cpu] = unit + i; unit_off[cpu] = gi->base_offset + i * ai->unit_size; @@ -1632,7 +1632,7 @@ int __init pcpu_setup_first_chunk(const pcpu_nr_units = unit;
for_each_possible_cpu(cpu) - BUG_ON(unit_map[cpu] == NR_CPUS); + BUG_ON(unit_map[cpu] == UINT_MAX);
pcpu_nr_groups = ai->nr_groups; pcpu_group_offsets = group_offsets;
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