[PATCH net-next 1/2] hsr: annotate data-race around hsr->sequence_nr

[Eric Dumazet <edumazet@google.com>]

hsr->sequence_nr is incremented from the transmit paths under
hsr->seqnr_lock, but hsr_fill_info() reads it without holding
this lock.

Use WRITE_ONCE() in the two writers, so that a matching
READ_ONCE() can be used in hsr_fill_info().

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/hsr/hsr_device.c  | 2 +-
 net/hsr/hsr_forward.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c
index d14de44e14b7a9f451cf24fdd20b70d77eb623b7..fc512204600cd83b08bcaaff28bcaf44ea044f1d 100644
--- a/net/hsr/hsr_device.c
+++ b/net/hsr/hsr_device.c
@@ -333,7 +333,7 @@ static void send_hsr_supervision_frame(struct hsr_port *port,
 		hsr->sup_sequence_nr++;
 	} else {
 		hsr_stag->sequence_nr = htons(hsr->sequence_nr);
-		hsr->sequence_nr++;
+		WRITE_ONCE(hsr->sequence_nr, hsr->sequence_nr + 1);
 	}
 
 	hsr_stag->tlv.HSR_TLV_type = type;
diff --git a/net/hsr/hsr_forward.c b/net/hsr/hsr_forward.c
index 7734a521a96c23f6a9c18c03ae239fb12e55bee0..44f6d9c83180a6316b06afef1af9bbdb2e340f75 100644
--- a/net/hsr/hsr_forward.c
+++ b/net/hsr/hsr_forward.c
@@ -645,7 +645,7 @@ static void handle_std_frame(struct sk_buff *skb,
 		/* Sequence nr for the master/interlink node */
 		lockdep_assert_held(&hsr->seqnr_lock);
 		frame->sequence_nr = hsr->sequence_nr;
-		hsr->sequence_nr++;
+		WRITE_ONCE(hsr->sequence_nr, hsr->sequence_nr + 1);
 	}
 }
 
-- 
2.55.0.1032.g73a4cd73de-goog