On Aug 17, 2021, at 10:04 AM, Gerd Rausch [off-list ref] wrote:

Function "dma_map_sg" is entitled to merge adjacent entries
and return a value smaller than what was passed as "nents".

Subsequently "ib_map_mr_sg" needs to work with this value ("sg_dma_len")
rather than the original "nents" parameter ("sg_len").

This old RDS bug was exposed and reliably causes kernel panics
(using RDMA operations "rds-stress -D") on x86_64 starting with:
commit c588072bba6b ("iommu/vt-d: Convert intel iommu driver to the iommu ops")

Simply put: Linux 5.11 and later.

Signed-off-by: Gerd Rausch <redacted>
---
net/rds/ib_frmr.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

Looks good to me Gerd. Thanks !!

Acked-by: Santosh Shilimkar <redacted>