The rps_resp buffer in ata_device is a DMA target, but it isn't explicitly cacheline aligned. Due to this, adjacent fields can be overwritten with stale data from memory on non-coherent architectures. As a result, the kernel is sometimes unable to communicate with an SATA device behind a SAS expander.

Fix this by ensuring that the rps_resp buffer is cacheline aligned.

This issue is similar to that fixed by Commit 84bda12af31f93 ("libata: align ap->sector_buf") and Commit 4ee34ea3a12396f35b26 ("libata: Align ata_device's id on a cacheline").

Cc: stable@vger.kernel.org Signed-off-by: Huacai Chen chenhc@lemote.com --- include/scsi/libsas.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h index 0f9cbf9..6df6fe0 100644 --- a/include/scsi/libsas.h +++ b/include/scsi/libsas.h @@ -159,11 +159,11 @@ struct expander_device {

struct sata_device { unsigned int class; - struct smp_resp rps_resp; /* report_phy_sata_resp */ u8 port_no; /* port number, if this is a PM (Port) */

struct ata_port *ap; struct ata_host ata_host; + struct smp_resp rps_resp ____cacheline_aligned; /* report_phy_sata_resp */ u8 fis[ATA_RESP_FIS_SIZE]; };