On 5/29/24 10:48 PM, Li RongQing wrote:
> list_for_each_entry_safe() should be used when the descriptor will be
> freed in idxd_desc_complete(), Otherwise the freed descriptor will be
> dereferenced to get its next, and always deletes freed descriptor from
> list firstly
Maybe say it like this:
Use list_for_each_entry_safe() to allow iterating through the list and deleting the entry
in the iteration process. The descrptor is freed via idxd_desc_complete() and there's a
slight chance may cause issue for the list iterator when the descriptor is reused by another
thread without it being deleted from the list.
Otherwise
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
>
> Fixes: 16e19e11228b ("dmaengine: idxd: Fix list corruption in description completion")
> Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx>
> ---
> drivers/dma/idxd/irq.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
> index 8dc029c..fc049c9 100644
> --- a/drivers/dma/idxd/irq.c
> +++ b/drivers/dma/idxd/irq.c
> @@ -611,11 +611,13 @@ static void irq_process_work_list(struct idxd_irq_entry *irq_entry)
>
> spin_unlock(&irq_entry->list_lock);
>
> - list_for_each_entry(desc, &flist, list) {
> + list_for_each_entry_safe(desc, n, &flist, list) {
> /*
> * Check against the original status as ABORT is software defined
> * and 0xff, which DSA_COMP_STATUS_MASK can mask out.
> */
> + list_del(&desc->list);
> +
> if (unlikely(desc->completion->status == IDXD_COMP_DESC_ABORT)) {
> idxd_desc_complete(desc, IDXD_COMPLETE_ABORT, true);
> continue;
