From: Aharon Landau aharonl@nvidia.com
[ Upstream commit b79f2dc5ffe17b03ec8c55f0d63f65e87bcac676 ]
rounddown_pow_of_two() is undefined when the input is 0. Therefore we need to avoid it in ib_umem_find_best_pgsz and return 0. Otherwise, it could result in not rejecting an invalid page size which eventually causes a kernel oops due to the logical inconsistency.
Fixes: 3361c29e9279 ("RDMA/umem: Use simpler logic for ib_umem_find_best_pgsz()") Link: https://lore.kernel.org/r/20210113121703.559778-2-leon@kernel.org Signed-off-by: Aharon Landau aharonl@nvidia.com Reviewed-by: Jason Gunthorpe jgg@nvidia.com Reviewed-by: Maor Gottlieb maorg@mellanox.com Signed-off-by: Leon Romanovsky leonro@nvidia.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/infiniband/core/umem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c index e9fecbdf391bc..5157ae29a4460 100644 --- a/drivers/infiniband/core/umem.c +++ b/drivers/infiniband/core/umem.c @@ -126,7 +126,7 @@ unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem, */ if (mask) pgsz_bitmap &= GENMASK(count_trailing_zeros(mask), 0); - return rounddown_pow_of_two(pgsz_bitmap); + return pgsz_bitmap ? rounddown_pow_of_two(pgsz_bitmap) : 0; } EXPORT_SYMBOL(ib_umem_find_best_pgsz);