| Message ID | 20210908081849.7948-1-schnelle@linux.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Jason Gunthorpe |
| Headers | show |
| Series | [RESEND,1/2] RDMA/mlx5: Fix number of allocated XLT entries | expand |
On Wed, Sep 08, 2021 at 10:18:48AM +0200, Niklas Schnelle wrote: > In commit 8010d74b9965b ("RDMA/mlx5: Split the WR setup out of > mlx5_ib_update_xlt()") the allocation logic was split out of > mlx5_ib_update_xlt() and the logic was changed to enable better OOM > handling. Sadly this change introduced a miscalculation of the number of > entries that were actually allocated when under memory pressure where it > can actually become 0 which on s390 lets dma_map_single() fail. > > It can also lead to corruption of the free pages list when the wrong > number of entries is used in the calculation of sg->length which is used > as argument for free_pages(). > > Fix this by using the allocation size instead of misusing > get_order(size). > > Cc: stable@vger.kernel.org > Fixes: 8010d74b9965b ("RDMA/mlx5: Split the WR setup out of mlx5_ib_update_xlt()") > Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> > --- > drivers/infiniband/hw/mlx5/mr.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Both patches applied to for-rc, thanks Jason
diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c index 3f1c5a4f158b..19713cdd7b78 100644 --- a/drivers/infiniband/hw/mlx5/mr.c +++ b/drivers/infiniband/hw/mlx5/mr.c @@ -1024,7 +1024,7 @@ static void *mlx5_ib_alloc_xlt(size_t *nents, size_t ent_size, gfp_t gfp_mask) if (size > MLX5_SPARE_UMR_CHUNK) { size = MLX5_SPARE_UMR_CHUNK; - *nents = get_order(size) / ent_size; + *nents = size / ent_size; res = (void *)__get_free_pages(gfp_mask | __GFP_NOWARN, get_order(size)); if (res)
In commit 8010d74b9965b ("RDMA/mlx5: Split the WR setup out of mlx5_ib_update_xlt()") the allocation logic was split out of mlx5_ib_update_xlt() and the logic was changed to enable better OOM handling. Sadly this change introduced a miscalculation of the number of entries that were actually allocated when under memory pressure where it can actually become 0 which on s390 lets dma_map_single() fail. It can also lead to corruption of the free pages list when the wrong number of entries is used in the calculation of sg->length which is used as argument for free_pages(). Fix this by using the allocation size instead of misusing get_order(size). Cc: stable@vger.kernel.org Fixes: 8010d74b9965b ("RDMA/mlx5: Split the WR setup out of mlx5_ib_update_xlt()") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> --- drivers/infiniband/hw/mlx5/mr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)