Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 320661b0 authored by Tahsin Erdogan's avatar Tahsin Erdogan Committed by Tejun Heo
Browse files

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: b539b87f ("percpu: implmeent pcpu_nr_empty_pop_pages and chunk->nr_populated")
Signed-off-by: default avatarTahsin Erdogan <tahsin@google.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org # v3.18+
parent c1ae3cfa

mm/percpu.c

+4 −1
Original line number Diff line number Diff line
@@ -1011,8 +1011,11 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved, 
		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();