Dear James, dear all, this is to let you know that I'll not pursue this issue further. I spent some days building a test system, but I could not reproduce the error. There's a tool named HUGO by HGST/Western Digital to re-configure the HDD's firmware to use 512byte blocks, which solved the problem for me. Sorry about the bad news. Yours, Sebastian Am 14.06.2018 um 14:11 schrieb Sebastian Hegler <sebastian.hegler@xxxxxxxxxxxxx>: > Dear James, dear all! > > Am 11.06.2018 um 17:06 schrieb James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>: >> This means that somehow, something sent a non 4k aligned 4k sized >> request. SCSI here is just the messenger. However, if you apply this >> patch, it will capture the stack trace of what above it triggered this, >> which may help us in debugging. It could be we may also want to see >> what the values of block and blk_rq_sectors(rq) actually are, but lets >> begin with the stack trace. >> --- >> >> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c >> index 9421d9877730..ac865e048533 100644 >> --- a/drivers/scsi/sd.c >> +++ b/drivers/scsi/sd.c >> @@ -1109,6 +1109,7 @@ static int sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt) >> if ((block & 7) || (blk_rq_sectors(rq) & 7)) { >> scmd_printk(KERN_ERR, SCpnt, >> "Bad block number requested\n"); >> + WARN_ON_ONCE(1); >> goto out; >> } else { >> block = block >> 3; > I'll give that a try. But don't expect to hear from me soon, I'll need to build a test system for that. The error occurred in a production system, which I am very hesitant to re-boot, let alone insert drives that cause error messages. > > Yours sincerely, > Sebastian