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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Gerd Rausch <gerd.rausch@oracle.com>,
	Santosh Shilimkar <santosh.shilimkar@oracle.com>,
	Jakub Kicinski <kuba@kernel.org>, Sasha Levin <sashal@kernel.org>,
	netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
	rds-devel@oss.oracle.com
Subject: [PATCH AUTOSEL 4.19 10/10] net/rds: dma_map_sg is entitled to merge entries
Date: Mon, 23 Aug 2021 20:55:12 -0400	[thread overview]
Message-ID: <20210824005513.631557-10-sashal@kernel.org> (raw)
In-Reply-To: <20210824005513.631557-1-sashal@kernel.org>

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 6431a023ac89..46988c009a3e 100644
--- a/net/rds/ib_frmr.c
+++ b/net/rds/ib_frmr.c
@@ -111,9 +111,9 @@ 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


      parent reply	other threads:[~2021-08-24  1:01 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-24  0:55 [PATCH AUTOSEL 4.19 01/10] opp: remove WARN when no valid OPPs remain Sasha Levin
2021-08-24  0:55 ` [PATCH AUTOSEL 4.19 02/10] virtio: Improve vq->broken access to avoid any compiler optimization Sasha Levin
2021-08-24  0:55 ` [PATCH AUTOSEL 4.19 03/10] virtio_pci: Support surprise removal of virtio pci device Sasha Levin
2021-08-24  0:55 ` [PATCH AUTOSEL 4.19 04/10] vringh: Use wiov->used to check for read/write desc order Sasha Levin
2021-08-24  0:55 ` [PATCH AUTOSEL 4.19 05/10] qed: qed ll2 race condition fixes Sasha Levin
2021-08-24  0:55 ` [PATCH AUTOSEL 4.19 06/10] qed: Fix null-pointer dereference in qed_rdma_create_qp() Sasha Levin
2021-08-24  0:55 ` [PATCH AUTOSEL 4.19 07/10] drm: Copy drm_wait_vblank to user before returning Sasha Levin
2021-08-24  0:55 ` [PATCH AUTOSEL 4.19 08/10] drm/nouveau/disp: power down unused DP links during init Sasha Levin
2021-08-24  0:55 ` [PATCH AUTOSEL 4.19 09/10] drm/nouveau: block a bunch of classes from userspace Sasha Levin
2021-08-24  0:55 ` Sasha Levin [this message]

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