| Message ID | 20221117012804.62514-1-daniel.m.jordan@oracle.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | padata: Fix list iterator in padata_do_serial() | expand |
On Wed, Nov 16, 2022 at 08:28:04PM -0500, Daniel Jordan wrote: > 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: bfde23ce200e ("padata: unbind parallel jobs from specific CPUs") > Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com> > --- > kernel/padata.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) Patch applied. Thanks.
diff --git a/kernel/padata.c b/kernel/padata.c index 97f51e0c1776..de90af5fcbe6 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -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); /*
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: bfde23ce200e ("padata: unbind parallel jobs from specific CPUs") Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com> --- kernel/padata.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)