| Message ID | 370458fcfbbd452381ad0f8787293455@rohde-schwarz.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] padata: use integer wrap around to prevent deadlock on seq_nr overflow | expand |
diff --git a/kernel/padata.c b/kernel/padata.c index 53f4bc912712..222bccd0c96b 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -404,7 +404,8 @@ void padata_do_serial(struct padata_priv *padata) /* Sort in ascending order of sequence number. */ list_for_each_prev(pos, &reorder->list) { cur = list_entry(pos, struct padata_priv, list); - if (cur->seq_nr < padata->seq_nr) + /* Compare by difference to consider integer wrap around */ + if ((signed int)(cur->seq_nr - padata->seq_nr) < 0) break; } list_add(&padata->list, pos);
When submitting more than 2^32 padata objects to padata_do_serial, the current sorting implementation incorrectly sorts padata objects with overflowed seq_nr, causing them to be placed before existing objects in the reorder list. This leads to a deadlock in the serialization process as padata_find_next cannot match padata->seq_nr and pd->processed because the padata instance with overflowed seq_nr will be selected next. To fix this, we use an unsigned integer wrap around to correctly sort padata objects in scenarios with integer overflow. Fixes: bfde23ce200e ("padata: unbind parallel jobs from specific CPUs") Co-developed-by: Christian Gafert <christian.gafert@rohde-schwarz.com> Signed-off-by: Christian Gafert <christian.gafert@rohde-schwarz.com> Co-developed-by: Max Ferger <max.ferger@rohde-schwarz.com> Signed-off-by: Max Ferger <max.ferger@rohde-schwarz.com> Signed-off-by: Van Giang Nguyen <vangiang.nguyen@rohde-schwarz.com> Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com> --- v2: include Fixes tag and Daniel's Acked-by tag v1: https://lore.kernel.org/a16995232eda4d39812f4bd94d9fb846@rohde-schwarz.com kernel/padata.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)