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| author | Tejun Heo <tj@kernel.org> | 2012-04-27 08:42:53 -0700 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2012-05-09 10:08:16 -0700 |
| commit | 42b64281453249dac52861f9b97d18552a7ec62b (patch) | |
| tree | 1a9ca6f44ee7834c5b0a9757631534452b0fc3bd /mm/percpu.c | |
| parent | 789505b05752239d957dbfa84b183e0d7a641952 (diff) | |
| download | linux-42b64281453249dac52861f9b97d18552a7ec62b.tar.gz | |
percpu: pcpu_embed_first_chunk() should free unused parts after all allocs are complete
pcpu_embed_first_chunk() allocates memory for each node, copies percpu data and frees unused portions of it before proceeding to the next group. This assumes that allocations for different nodes doesn't overlap; however, depending on memory topology, the bootmem allocator may end up allocating memory from a different node than the requested one which may overlap with the portion freed from one of the previous percpu areas. This leads to percpu groups for different nodes overlapping which is a serious bug. This patch separates out copy & partial free from the allocation loop such that all allocations are complete before partial frees happen. This also fixes overlapping frees which could happen on allocation failure path - out_free_areas path frees whole groups but the groups could have portions freed at that point. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org Reported-by: "Pavel V. Panteleev" <pp_84@mail.ru> Tested-by: "Pavel V. Panteleev" <pp_84@mail.ru> LKML-Reference: <E1SNhwY-0007ui-V7.pp_84-mail-ru@f220.mail.ru>
Diffstat (limited to 'mm/percpu.c')
| -rw-r--r-- | mm/percpu.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/mm/percpu.c b/mm/percpu.c index f921fdfb5430..ac5c626b44a9 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -1650,6 +1650,16 @@ int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size, areas[group] = ptr; base = min(ptr, base); + } + + /* + * Copy data and free unused parts. This should happen after all + * allocations are complete; otherwise, we may end up with + * overlapping groups. + */ + for (group = 0; group < ai->nr_groups; group++) { + struct pcpu_group_info *gi = &ai->groups[group]; + void *ptr = areas[group]; for (i = 0; i < gi->nr_units; i++, ptr += ai->unit_size) { if (gi->cpu_map[i] == NR_CPUS) { |