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| author | Tahsin Erdogan <tahsin@google.com> | 2017-02-25 13:00:19 -0800 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2017-03-06 15:55:39 -0500 |
| commit | 320661b08dd6f1746d5c7ab4eb435ec64b97cd45 (patch) | |
| tree | bb7249336a8e2d2ab0d2d22689a5737dd78bf3e0 /mm/percpu.c | |
| parent | c1ae3cfa0e89fa1a7ecc4c99031f5e9ae99d9201 (diff) | |
| download | linux-320661b08dd6f1746d5c7ab4eb435ec64b97cd45.tar.gz linux-320661b08dd6f1746d5c7ab4eb435ec64b97cd45.tar.bz2 linux-320661b08dd6f1746d5c7ab4eb435ec64b97cd45.zip | |
percpu: acquire pcpu_lock when updating pcpu_nr_empty_pop_pages
Update to pcpu_nr_empty_pop_pages in pcpu_alloc() is currently done
without holding pcpu_lock. This can lead to bad updates to the variable.
Add missing lock calls.
Fixes: b539b87fed37 ("percpu: implmeent pcpu_nr_empty_pop_pages and chunk->nr_populated")
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org # v3.18+
Diffstat (limited to 'mm/percpu.c')
| -rw-r--r-- | mm/percpu.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/mm/percpu.c b/mm/percpu.c index 5696039b5c07..60a6488e9e6d 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -1011,8 +1011,11 @@ area_found: mutex_unlock(&pcpu_alloc_mutex); } - if (chunk != pcpu_reserved_chunk) + if (chunk != pcpu_reserved_chunk) { + spin_lock_irqsave(&pcpu_lock, flags); pcpu_nr_empty_pop_pages -= occ_pages; + spin_unlock_irqrestore(&pcpu_lock, flags); + } if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW) pcpu_schedule_balance_work(); |