This is a note to let you know that I've just added the patch titled scsi: tracing: Fix handling of TRANSFER LENGTH == 0 for READ(6) and WRITE(6) to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: scsi-tracing-fix-handling-of-transfer-length-0-for-r.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit c393f4200cad7c6ae85add36872a2724ed57f0a2 Author: Bart Van Assche <bvanassche@xxxxxxx> Date: Tue Nov 5 13:55:53 2019 -0800 scsi: tracing: Fix handling of TRANSFER LENGTH == 0 for READ(6) and WRITE(6) [ Upstream commit f6b8540f40201bff91062dd64db8e29e4ddaaa9d ] According to SBC-2 a TRANSFER LENGTH field of zero means that 256 logical blocks must be transferred. Make the SCSI tracing code follow SBC-2. Fixes: bf8162354233 ("[SCSI] add scsi trace core functions and put trace points") Cc: Christoph Hellwig <hch@xxxxxx> Cc: Hannes Reinecke <hare@xxxxxxxx> Cc: Douglas Gilbert <dgilbert@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20191105215553.185018-1-bvanassche@xxxxxxx Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/scsi/scsi_trace.c b/drivers/scsi/scsi_trace.c index 0ff083bbf5b1..617a60737590 100644 --- a/drivers/scsi/scsi_trace.c +++ b/drivers/scsi/scsi_trace.c @@ -30,15 +30,18 @@ static const char * scsi_trace_rw6(struct trace_seq *p, unsigned char *cdb, int len) { const char *ret = trace_seq_buffer_ptr(p); - sector_t lba = 0, txlen = 0; + u32 lba = 0, txlen; lba |= ((cdb[1] & 0x1F) << 16); lba |= (cdb[2] << 8); lba |= cdb[3]; - txlen = cdb[4]; + /* + * From SBC-2: a TRANSFER LENGTH field set to zero specifies that 256 + * logical blocks shall be read (READ(6)) or written (WRITE(6)). + */ + txlen = cdb[4] ? cdb[4] : 256; - trace_seq_printf(p, "lba=%llu txlen=%llu", - (unsigned long long)lba, (unsigned long long)txlen); + trace_seq_printf(p, "lba=%u txlen=%u", lba, txlen); trace_seq_putc(p, 0); return ret;