From f3a1ac258ebcb741e04623b2329bd9a9582d7fcf Mon Sep 17 00:00:00 2001 From: Gerd Rausch Date: Tue, 17 Aug 2021 10:04:37 -0700 Subject: [PATCH] net/rds: dma_map_sg is entitled to merge entries [ Upstream commit fb4b1373dcab086d0619c29310f0466a0b2ceb8a ] 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 Acked-by: Santosh Shilimkar Link: https://lore.kernel.org/r/60efc69f-1f35-529d-a7ef-da0549cad143@oracle.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/rds/ib_frmr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/rds/ib_frmr.c b/net/rds/ib_frmr.c index 06ecf9d2d4bf..ef6acd721118 100644 --- a/net/rds/ib_frmr.c +++ b/net/rds/ib_frmr.c @@ -131,9 +131,9 @@ static int rds_ib_post_reg_frmr(struct rds_ib_mr *ibmr) cpu_relax(); } - ret = ib_map_mr_sg_zbva(frmr->mr, ibmr->sg, ibmr->sg_len, + ret = ib_map_mr_sg_zbva(frmr->mr, ibmr->sg, ibmr->sg_dma_len, &off, PAGE_SIZE); - if (unlikely(ret != ibmr->sg_len)) + if (unlikely(ret != ibmr->sg_dma_len)) return ret < 0 ? ret : -EINVAL; if (cmpxchg(&frmr->fr_state,