This fixes random memory corruption triggered when all three of the following are true:
* scsi-mq enabled * T10 Protection Information (DIF) enabled * SCSI host with sg_tablesize > SCSI_MAX_SG_SEGMENTS (128) The symptoms of this bug are unpredictable memory corruption, BUG()s, oopses, lockups, etc., any of which may appear to be completely unrelated to the root cause. Cc: <sta...@vger.kernel.org> # 3.17.x, 3.18.x Signed-off-by: Tony Battersby <to...@cybernetics.com> --- I encountered this problem with a QLogic QLE2672 FC HBA using qla2xxx. On my system, this would trigger BUG_ON(atomic_read(&bio->bi_remaining) <= 0) in bio_endio(), or a general protection fault in __sg_free_table() trying to free prot_sdb, or any number of other weird random problems. All of this was caused by cmd->prot_sdb pointing to the wrong memory. To see how the memory is allocated, refer to scsi_mq_setup_tags() in scsi_lib.c. For inclusion in 3.19, 3.18.x, and 3.17.x. --- linux-3.18.0/drivers/scsi/scsi_lib.c.orig 2014-12-08 16:23:28.000000000 -0500 +++ linux-3.18.0/drivers/scsi/scsi_lib.c 2014-12-08 16:24:00.000000000 -0500 @@ -1829,7 +1829,9 @@ static int scsi_mq_prep_fn(struct reques if (scsi_host_get_prot(shost)) { cmd->prot_sdb = (void *)sg + - shost->sg_tablesize * sizeof(struct scatterlist); + min_t(unsigned int, + shost->sg_tablesize, SCSI_MAX_SG_SEGMENTS) * + sizeof(struct scatterlist); memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer)); cmd->prot_sdb->table.sgl = -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/