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authorAharon Landau <aharonl@nvidia.com>2021-01-13 14:16:59 +0200
committerJason Gunthorpe <jgg@nvidia.com>2021-01-14 12:50:17 -0400
commitb79f2dc5ffe17b03ec8c55f0d63f65e87bcac676 (patch)
tree895aa1515365389bda7639cb958c85f55ff739c8 /drivers
parentf2bc3af6353cb2a33dfa9d270d999d839eef54cb (diff)
downloadlinux-b79f2dc5ffe17b03ec8c55f0d63f65e87bcac676.tar.bz2
RDMA/umem: Avoid undefined behavior of rounddown_pow_of_two()
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/infiniband/core/umem.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index 7ca4112e3e8f..917338db7ac1 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -135,7 +135,7 @@ 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);