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authorTahsin Erdogan <tahsin@google.com>2017-02-25 13:00:19 -0800
committerTejun Heo <tj@kernel.org>2017-03-06 15:55:39 -0500
commit320661b08dd6f1746d5c7ab4eb435ec64b97cd45 (patch)
treebb7249336a8e2d2ab0d2d22689a5737dd78bf3e0 /mm
parentc1ae3cfa0e89fa1a7ecc4c99031f5e9ae99d9201 (diff)
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')
-rw-r--r--mm/percpu.c5
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();