[PATCH] amd64_edac: Fix hypothetical out-of-bounds access

[Denis Kirjanov]

Make sure we stay within scrubrates' array bounds.

Boris: this is a correctness fix only because the loop terminates
earlier due to us capping scrubbing bandwidth to 0.

Signed-off-by: Denis Kirjanov <kirjanov@xxxxxxxxx>
Signed-off-by: Borislav Petkov <borislav.petkov@xxxxxxx>
---
 drivers/edac/amd64_edac.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 501bfb938f26..73d9108d6200 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -181,14 +181,16 @@ static int __amd64_set_scrub_rate(struct pci_dev *ctl, u32 new_bw, u32 min_rate)
 
 		if (scrubrates[i].bandwidth <= new_bw)
 			break;
-
-		/*
-		 * if no suitable bandwidth found, turn off DRAM scrubbing
-		 * entirely by falling back to the last element in the
-		 * scrubrates array.
-		 */
 	}
 
+	/*
+	 * if no suitable bandwidth found, turn off DRAM scrubbing
+	 * entirely by falling back to the last element in the scrubrates
+	 * array.
+	 */
+	if (i == ARRAY_SIZE(scrubrates))
+		i--;
+
 	scrubval = scrubrates[i].scrubval;
 
 	pci_write_bits32(ctl, SCRCTRL, scrubval, 0x001F);
-- 
1.8.0

Thanks.

-- 
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
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