From: Arthur Kiyanovski Date: Thu, 4 Jun 2026 08:07:04 +0000 (+0000) Subject: net: ena: PHC: Add missing barrier X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=954981dbbfbd78f21d2fbac1ac0742dbf38b4e69;p=thirdparty%2Fkernel%2Flinux.git net: ena: PHC: Add missing barrier Add dma_rmb() barrier after req_id completion check in ena_com_phc_get_timestamp(). On weakly-ordered architectures, payload fields may be read before req_id is observed as updated. Fixes: e0ea34158ee8 ("net: ena: Add PHC support in the ENA driver") Closes: https://sashiko.dev/#/patchset/20260430032507.11586-1-akiyano%40amazon.com Signed-off-by: Arthur Kiyanovski Signed-off-by: Jakub Kicinski --- diff --git a/drivers/net/ethernet/amazon/ena/ena_com.c b/drivers/net/ethernet/amazon/ena/ena_com.c index 8c86789d867a5..297fb36ab8c16 100644 --- a/drivers/net/ethernet/amazon/ena/ena_com.c +++ b/drivers/net/ethernet/amazon/ena/ena_com.c @@ -1880,6 +1880,11 @@ int ena_com_phc_get_timestamp(struct ena_com_dev *ena_dev, u64 *timestamp) continue; } + /* Ensure PHC payload (timestamp, error_flags) is read + * after req_id update is observed + */ + dma_rmb(); + /* req_id was updated by the device which indicates that * PHC timestamp and error_flags are updated too, * checking errors before retrieving timestamp