Patchwork [148/150] bnx2x: fix occasional statistics off-by-4GB error

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Submitter Luis Henriques
Date March 26, 2013, 3:20 p.m.
Message ID <1364311249-14454-149-git-send-email-luis.henriques@canonical.com>
Download mbox | patch
Permalink /patch/231407/
State New
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Luis Henriques - March 26, 2013, 3:20 p.m.
3.5.7.9 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: =?UTF-8?q?Maciej=20=C5=BBenczykowski?= <maze@google.com>

commit b009aac12cd0fe34293c68af8ac48b85be3bd858 upstream.

The UPDATE_QSTAT function introduced on February 15, 2012
in commit 1355b704b9ba "bnx2x: consistent statistics after
internal driver reload" incorrectly fails to handle overflow
during addition of the lower 32-bit field of a stat.

This bug is present since 3.4-rc1 and should thus be considered
a candidate for stable 3.4+ releases.

Google-Bug-Id: 8374428
Signed-off-by: Maciej ┼╗enczykowski <maze@google.com>
Cc: Mintz Yuval <yuvalmin@broadcom.com>
Acked-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Patch

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.h b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.h
index 93e689fd..c664a61 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.h
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.h
@@ -451,8 +451,9 @@  struct bnx2x_fw_port_stats_old {
 
 #define UPDATE_QSTAT(s, t) \
 	do { \
-		qstats->t##_hi = qstats_old->t##_hi + le32_to_cpu(s.hi); \
 		qstats->t##_lo = qstats_old->t##_lo + le32_to_cpu(s.lo); \
+		qstats->t##_hi = qstats_old->t##_hi + le32_to_cpu(s.hi) \
+			+ ((qstats->t##_lo < qstats_old->t##_lo) ? 1 : 0); \
 	} while (0)
 
 #define UPDATE_QSTAT_OLD(f) \