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From: Richard Cheng <icheng@nvidia.com>
To: dave@stgolabs.net, jic23@kernel.org, dave.jiang@intel.com,
	alison.schofield@intel.com, vishal.l.verma@intel.com
Cc: iweiny@kernel.org, ming.li@zohomail.com, gourry@gourry.net,
	rrichter@amd.com, linux-cxl@vger.kernel.org,
	linux-kernel@vger.kernel.org, kees@kernel.org,
	newtonl@nvidia.com, kristinc@nvidia.com, kaihengf@nvidia.com,
	kobak@nvidia.com, Richard Cheng <icheng@nvidia.com>
Subject: [PATCH v4 6/6] cxl/region: Reject poison scan for decoder without a partition
Date: Wed, 12 Aug 2026 19:21:07 +0800	[thread overview]
Message-ID: <20260812112107.56181-7-icheng@nvidia.com> (raw)
In-Reply-To: <20260812112107.56181-1-icheng@nvidia.com>

__cxl_dpa_reserve() may leave cxled->part at -1 when a decoder's DPA
range doesn't map to any reported partition, while still keeping
dpa_res. poison_by_decoder() then indexes cxlds->part[-1], causing an
out-of-bounds read when poison collection is triggered.

Return -ENODEV before accessing the partition array when no partition was
assigned.

Fixes: be5cbd084027 ("cxl: Kill enum cxl_decoder_mode")
Signed-off-by: Richard Cheng <icheng@nvidia.com>
---
 drivers/cxl/core/region.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index b7dc5d4988da..afe3fb57b7fe 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -2954,6 +2954,8 @@ static int poison_by_decoder(struct device *dev, void *arg)
 	cxled = to_cxl_endpoint_decoder(dev);
 	if (!cxled->dpa_res)
 		return rc;
+	if (cxled->part < 0)
+		return -ENODEV;
 
 	cxlmd = cxled_to_memdev(cxled);
 	cxlds = cxlmd->cxlds;
-- 
2.43.0


  parent reply	other threads:[~2026-08-12 11:22 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-12 11:21 [PATCH v4 0/6] cxl: Sashiko bug fixes Richard Cheng
2026-08-12 11:21 ` [PATCH v4 1/6] cxl/features: Reject feature offset that overflows 16-bit field Richard Cheng
2026-08-12 11:52   ` sashiko-bot
2026-08-12 11:21 ` [PATCH v4 2/6] cxl/region: Scan all partitions for unmapped poison Richard Cheng
2026-08-12 11:21 ` [PATCH v4 3/6] cxl/region: Don't leak tolerated RAM -EFAULT from unmapped poison scan Richard Cheng
2026-08-12 12:08   ` sashiko-bot
2026-08-12 11:21 ` [PATCH v4 4/6] cxl/region: Start unmapped poison scan at the committed decoder boundary Richard Cheng
2026-08-12 11:21 ` [PATCH v4 5/6] cxl/memdev: Don't overwrite the error from an earlier partition poison query Richard Cheng
2026-08-12 11:21 ` Richard Cheng [this message]
2026-08-12 12:41   ` [PATCH v4 6/6] cxl/region: Reject poison scan for decoder without a partition sashiko-bot

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