Thank you for the review. I re-sent updated patch, please take a look. Best regards, Hyejeong
On Mon, May 12, 2025 at 03:16:33PM +0200, Christian König wrote: > On 5/12/25 13:12, Hyejeong Choi wrote: > > smp_store_mb() inserts memory barrier after storing operation. > > It is different with what the comment is originally aiming so Null > > pointer dereference can be happened if memory update is reordered. > > > > Signed-off-by: Hyejeong Choi <hjeong.c...@samsung.com> > > --- > > drivers/dma-buf/dma-resv.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c > > index 5f8d010516f0..52af5c7430da 100644 > > --- a/drivers/dma-buf/dma-resv.c > > +++ b/drivers/dma-buf/dma-resv.c > > @@ -320,8 +320,9 @@ void dma_resv_add_fence(struct dma_resv *obj, struct > > dma_fence *fence, > > count++; > > > > dma_resv_list_set(fobj, i, fence, usage); > > - /* pointer update must be visible before we extend the num_fences */ > > - smp_store_mb(fobj->num_fences, count); > > + /* fence update must be visible before we extend the num_fences */ > > + smp_wmb(); > > + WRITE_ONCE(fobj->num_fences, count); > > The WRITE_ONCE isn't necessary since smp_wmb() implies a compiler barrier, > but apart from that really good catch. > > Can you modify the patch and re-send? I will be pushing it to -fixes ASAP. > > Regards, > Christian. > > > } > > EXPORT_SYMBOL(dma_resv_add_fence); > > > > > > > >
