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authorTejun Heo <tj@kernel.org>2009-09-29 09:17:56 +0900
committerTejun Heo <tj@kernel.org>2009-09-29 09:17:56 +0900
commitffe0d5a575459ffe664b0762130b557f826fcace (patch)
treeaf581934a717c510a2c6897ca4ed7fcefd440578 /mm/percpu.c
parent17d857be649a21ca90008c6dc425d849fa83db5c (diff)
downloadlwn-ffe0d5a575459ffe664b0762130b557f826fcace.tar.gz
lwn-ffe0d5a575459ffe664b0762130b557f826fcace.zip
percpu: fix unit_map[] verification in pcpu_setup_first_chunk()
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-and-tested-by: Tony Vroon <tony@linx.net>
Diffstat (limited to 'mm/percpu.c')
-rw-r--r--mm/percpu.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/percpu.c b/mm/percpu.c
index 43d8cacfdaa5..e5c4cbda6026 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1604,7 +1604,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
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 struct pcpu_alloc_info *ai,
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 struct pcpu_alloc_info *ai,
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;