The following v3.4-rc1 commit unmasked an existing bug in
scsi_io_completion's SG_IO error handling:
47ac56d [SCSI] scsi_error: classify some ILLEGAL_REQUEST sense as a permanent TARGET_ERROR
Given that certain ILLEGAL_REQUEST are now properly categorized as
TARGET_ERROR the host_byte is being set (before host_byte wasn't ever
set for these ILLEGAL_REQUEST).
In scsi_io_completion, initialize req->errors with cmd->result _after_
the SG_IO block that calls __scsi_error_from_host_byte (which may
modify the host_byte).
Before this fix:
cdb to send: 12 01 01 00 00 00
ioctl(3, SG_IO, {'S', SG_DXFER_NONE, cmd[6]=[12, 01, 01, 00, 00, 00],
mx_sb_len=32, iovec_count=0, dxfer_len=0, timeout=20000, flags=0,
status=02, masked_status=01, sb[19]=[70, 00, 05, 00, 00, 00, 00, 0b,
00, 00, 00, 00, 24, 00, 00, 00, 00, 00, 00], host_status=0x10,
driver_status=0x8, resid=0, duration=0, info=0x1}) = 0
SCSI Status: Check Condition
Sense Information:
sense buffer empty
After:
cdb to send: 12 01 01 00 00 00
ioctl(3, SG_IO, {'S', SG_DXFER_NONE, cmd[6]=[12, 01, 01, 00, 00, 00],
mx_sb_len=32, iovec_count=0, dxfer_len=0, timeout=20000, flags=0,
status=02, masked_status=01, sb[19]=[70, 00, 05, 00, 00, 00, 00, 0b,
00, 00, 00, 00, 24, 00, 00, 00, 00, 00, 00], host_status=0,
driver_status=0x8, resid=0, duration=0, info=0x1}) = 0
SCSI Status: Check Condition
Sense Information:
Fixed format, current; Sense key: Illegal Request
Additional sense: Invalid field in cdb
Raw sense data (in hex):
70 00 05 00 00 00 00 0b 00 00 00 00 24 00 00 00
00 00 00
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Reported-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Tested-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Reviewed-by: Babu Moger <babu.moger@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx [v3.4+]
---
drivers/scsi/scsi_lib.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index b583277..9377ed2 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -759,7 +759,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
}
if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */
- req->errors = result;
if (result) {
if (sense_valid && req->sense) {
/*
@@ -775,6 +774,10 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
if (!sense_deferred)
error = __scsi_error_from_host_byte(cmd, result);
}
+ /*
+ * __scsi_error_from_host_byte may have reset the host_byte
+ */
+ req->errors = cmd->result;
req->resid_len = scsi_get_resid(cmd);
--
1.7.4.4
--
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