@@ -106,6 +106,7 @@ static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
{
struct idxd_desc *d, *t, *found = NULL;
struct llist_node *head;
+ LIST_HEAD(flist);
desc->completion->status = IDXD_COMP_DESC_ABORT;
/*
@@ -120,7 +121,11 @@ static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
found = desc;
continue;
}
- list_add_tail(&desc->list, &ie->work_list);
+
+ if (d->completion->status)
+ list_add_tail(&d->list, &flist);
+ else
+ list_add_tail(&d->list, &ie->work_list);
}
}
@@ -130,6 +135,17 @@ static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
if (found)
complete_desc(found, IDXD_COMPLETE_ABORT);
+
+ /*
+ * complete_desc() will return desc to allocator and the desc can be
+ * acquired by a different process and the desc->list can be modified.
+ * Delete desc from list so the list trasversing does not get corrupted
+ * by the other process.
+ */
+ list_for_each_entry_safe(d, t, &flist, list) {
+ list_del_init(&d->list);
+ complete_desc(d, IDXD_COMPLETE_NORMAL);
+ }
}
int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
Ming reported that with the abort path of the descriptor submission, there can be a window where a completed descriptor can be missed to be completed by the irq completion thread: CPU A CPU B Submit (successful) Submit (fail) irq_process_work_list() // empty llist_abort_desc() // remove all descs from pending list irq_process_pending_llist() // empty exit idxd_wq_thread() with no processing Add opportunistic descriptor completion in the abort path in order to remove the missed completion. Fixes: 6b4b87f2c31a ("dmaengine: idxd: fix submission race window") Reported-by: Ming Li <ming4.li@intel.com> Signed-off-by: Dave Jiang <dave.jiang@intel.com> --- drivers/dma/idxd/submit.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-)