Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.9 3/3] net/rds: dma_map_sg is entitled to merge entries | Date | Mon, 23 Aug 2021 20:55:39 -0400 |
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From: Gerd Rausch <gerd.rausch@oracle.com>
[ 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@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Link: https://lore.kernel.org/r/60efc69f-1f35-529d-a7ef-da0549cad143@oracle.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- 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 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 -- 2.30.2
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