This is a note to let you know that I've just added the patch titled
net/rds: dma_map_sg is entitled to merge entries
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-rds-dma_map_sg-is-entitled-to-merge-entries.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit be637ec7b1479e3e4453cbb18e0248f16a553a51
Author: Gerd Rausch <gerd.rausch@xxxxxxxxxx>
Date: Tue Aug 17 10:04:37 2021 -0700
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 <gerd.rausch@xxxxxxxxxx>
Acked-by: Santosh Shilimkar <santosh.shilimkar@xxxxxxxxxx>
Link: https://lore.kernel.org/r/60efc69f-1f35-529d-a7ef-da0549cad143@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/rds/ib_frmr.c b/net/rds/ib_frmr.c
index 3d9c4c6397c3..20d045faf07c 100644
--- a/net/rds/ib_frmr.c
+++ b/net/rds/ib_frmr.c
@@ -112,9 +112,9 @@ 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;
/* Perform a WR for the fast_reg_mr. Each individual page
