On Wed, Oct 18, 2023 at 07:33:37PM +0800, Hou Tao wrote: > From: Hou Tao <houtao1@xxxxxxxxxx> > > There is no need to acquire pcpu_lock for pcpu_chunk_addr_search(): > 1) both pcpu_first_chunk & pcpu_reserved_chunk must have been > initialized before the invocation of free_percpu(). > 2) The dynamically-created chunk must be valid before the per-cpu > pointers allocated from it are freed. > > So acquire pcpu_lock() after the invocation of pcpu_chunk_addr_search(). > > Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx> > --- > mm/percpu.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/mm/percpu.c b/mm/percpu.c > index 7b40b3963f10..76b9c5e63c56 100644 > --- a/mm/percpu.c > +++ b/mm/percpu.c > @@ -2267,12 +2267,10 @@ void free_percpu(void __percpu *ptr) > kmemleak_free_percpu(ptr); > > addr = __pcpu_ptr_to_addr(ptr); > - > - spin_lock_irqsave(&pcpu_lock, flags); > - > chunk = pcpu_chunk_addr_search(addr); > off = addr - chunk->base_addr; > > + spin_lock_irqsave(&pcpu_lock, flags); > size = pcpu_free_area(chunk, off); > > pcpu_memcg_free_hook(chunk, off, size); > -- > 2.29.2 > Acked-by: Dennis Zhou <dennis@xxxxxxxxxx> Thanks, Dennis
