padata: Fix list iterator in padata_do_serial()

[ Upstream commit 57ddfecc72 ]

list_for_each_entry_reverse() assumes that the iterated list is nonempty
and that every list_head is embedded in the same type, but its use in
padata_do_serial() breaks both rules.

This doesn't cause any issues now because padata_priv and padata_list
happen to have their list fields at the same offset, but we really
shouldn't be relying on that.

Fixes: bfde23ce20 ("padata: unbind parallel jobs from specific CPUs")
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Daniel Jordan 2022-11-16 20:28:04 -05:00 committed by Greg Kroah-Hartman
parent 6cfa9e60c0
commit ff28b8afb7
1 changed files with 5 additions and 2 deletions

View File

@ -390,13 +390,16 @@ void padata_do_serial(struct padata_priv *padata)
int hashed_cpu = padata_cpu_hash(pd, padata->seq_nr);
struct padata_list *reorder = per_cpu_ptr(pd->reorder_list, hashed_cpu);
struct padata_priv *cur;
struct list_head *pos;
spin_lock(&reorder->lock);
/* Sort in ascending order of sequence number. */
list_for_each_entry_reverse(cur, &reorder->list, list)
list_for_each_prev(pos, &reorder->list) {
cur = list_entry(pos, struct padata_priv, list);
if (cur->seq_nr < padata->seq_nr)
break;
list_add(&padata->list, &cur->list);
}
list_add(&padata->list, pos);
spin_unlock(&reorder->lock);
/*