| Message ID | 20180404175355.15982-1-bart.vanassche@wdc.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On 2018-04-04 01:53 PM, Bart Van Assche wrote: > Commit e39a97353e53 modified __scsi_error_from_host_byte() such > that that function translates DID_OK into BLK_STS_OK. However, > the description of that commit is wrong: it mentions that commit > 2a842acab109 introduced a bug in __scsi_error_from_host_byte() > although that commit did not change the behavior of that function. > Additionally, commit e39a97353e53 introduced a severe bug: it causes > commands that fail with hostbyte=DID_OK and driverbyte=DRIVER_SENSE > to be completed with BLK_STS_OK. Fix __scsi_error_from_host_byte() > by only translating good status values into BLK_STS_OK. > > Fixes: e39a97353e53 ("scsi: core: return BLK_STS_OK for DID_OK in __scsi_error_from_host_byte()") > Reported-by: Damien Le Moal <damien.lemoal@wdc.com> > Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> > Cc: Hannes Reinecke <hare@suse.com> > Cc: Douglas Gilbert <dgilbert@interlog.com> Reviewed-by: Douglas Gilbert <dgilbert@interlog.com> > Cc: Damien Le Moal <damien.lemoal@wdc.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: stable@vger.kernel.org > --- There is some urgency here as the faulty patch is in lk 4.16.0 release. My patch was prepared independently of seeing this one. Both do the job (mine has a redundant status_byte(result) in the conditional). And the function name is now completely misleading but due to the urgency, that can wait for another day. > Changes compared to v1: > - Modified __scsi_error_from_host_byte() such that it again returns > BLK_STS_OK for CONDITION MET and other result codes that represent > success. > > drivers/scsi/scsi_lib.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index 74a39db57d49..1496b34af409 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -736,7 +736,13 @@ static blk_status_t __scsi_error_from_host_byte(struct scsi_cmnd *cmd, > { > switch (host_byte(result)) { > case DID_OK: > - return BLK_STS_OK; > + /* > + * Also check the other bytes than the status byte in result > + * to handle the case when a SCSI LLD sets result to > + * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION. > + */ > + return scsi_status_is_good(result) && (result & ~0xff) == 0 ? > + BLK_STS_OK : BLK_STS_IOERR; > case DID_TRANSPORT_FAILFAST: > return BLK_STS_TRANSPORT; > case DID_TARGET_FAILURE: >
On 04/04/2018 10:53 AM, Bart Van Assche wrote: > Commit e39a97353e53 modified __scsi_error_from_host_byte() such > that that function translates DID_OK into BLK_STS_OK. However, > the description of that commit is wrong: it mentions that commit > 2a842acab109 introduced a bug in __scsi_error_from_host_byte() > although that commit did not change the behavior of that function. > Additionally, commit e39a97353e53 introduced a severe bug: it causes > commands that fail with hostbyte=DID_OK and driverbyte=DRIVER_SENSE > to be completed with BLK_STS_OK. Fix __scsi_error_from_host_byte() > by only translating good status values into BLK_STS_OK. > > Fixes: e39a97353e53 ("scsi: core: return BLK_STS_OK for DID_OK in __scsi_error_from_host_byte()") > Reported-by: Damien Le Moal <damien.lemoal@wdc.com> > Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> > Cc: Hannes Reinecke <hare@suse.com> > Cc: Douglas Gilbert <dgilbert@interlog.com> > Cc: Damien Le Moal <damien.lemoal@wdc.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: stable@vger.kernel.org > --- > > Changes compared to v1: > - Modified __scsi_error_from_host_byte() such that it again returns > BLK_STS_OK for CONDITION MET and other result codes that represent > success. > > drivers/scsi/scsi_lib.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index 74a39db57d49..1496b34af409 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -736,7 +736,13 @@ static blk_status_t __scsi_error_from_host_byte(struct scsi_cmnd *cmd, > { > switch (host_byte(result)) { > case DID_OK: > - return BLK_STS_OK; > + /* > + * Also check the other bytes than the status byte in result > + * to handle the case when a SCSI LLD sets result to > + * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION. > + */ > + return scsi_status_is_good(result) && (result & ~0xff) == 0 ? > + BLK_STS_OK : BLK_STS_IOERR; > case DID_TRANSPORT_FAILFAST: > return BLK_STS_TRANSPORT; > case DID_TARGET_FAILURE: > Reviewed-by: Lee Duncan <lduncan@suse.com>
On Wed, 2018-04-04 at 10:53 -0700, Bart Van Assche wrote: > Commit e39a97353e53 modified __scsi_error_from_host_byte() such > that that function translates DID_OK into BLK_STS_OK. However, > the description of that commit is wrong: it mentions that commit > 2a842acab109 introduced a bug in __scsi_error_from_host_byte() > although that commit did not change the behavior of that function. > Additionally, commit e39a97353e53 introduced a severe bug: it causes > commands that fail with hostbyte=DID_OK and driverbyte=DRIVER_SENSE > to be completed with BLK_STS_OK. Fix __scsi_error_from_host_byte() > by only translating good status values into BLK_STS_OK. > > Fixes: e39a97353e53 ("scsi: core: return BLK_STS_OK for DID_OK in > __scsi_error_from_host_byte()") > Reported-by: Damien Le Moal <damien.lemoal@wdc.com> > Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> > Cc: Hannes Reinecke <hare@suse.com> > Cc: Douglas Gilbert <dgilbert@interlog.com> > Cc: Damien Le Moal <damien.lemoal@wdc.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: stable@vger.kernel.org > --- > > Changes compared to v1: > - Modified __scsi_error_from_host_byte() such that it again returns > BLK_STS_OK for CONDITION MET and other result codes that represent > success. > > drivers/scsi/scsi_lib.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index 74a39db57d49..1496b34af409 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -736,7 +736,13 @@ static blk_status_t __scsi_error_from_host_byte(struct > scsi_cmnd *cmd, > { > switch (host_byte(result)) { > case DID_OK: > - return BLK_STS_OK; > + /* > + * Also check the other bytes than the status byte in > result > + * to handle the case when a SCSI LLD sets result to > + * DRIVER_SENSE << 24 without setting > SAM_STAT_CHECK_CONDITION. > + */ > + return scsi_status_is_good(result) && (result & ~0xff) == 0 > ? > + BLK_STS_OK : BLK_STS_IOERR; This fixes the problem on my system. Tested-by: Damien Le Moal <damien.lemoal@wdc.com> -- Damien Le Moal Western Digital
On Wed, 4 Apr 2018 10:53:55 -0700 "Bart Van Assche" <bart.vanassche@wdc.com> wrote: > Commit e39a97353e53 modified __scsi_error_from_host_byte() such > that that function translates DID_OK into BLK_STS_OK. However, > the description of that commit is wrong: it mentions that commit > 2a842acab109 introduced a bug in __scsi_error_from_host_byte() > although that commit did not change the behavior of that function. > Additionally, commit e39a97353e53 introduced a severe bug: it causes > commands that fail with hostbyte=DID_OK and driverbyte=DRIVER_SENSE > to be completed with BLK_STS_OK. Fix __scsi_error_from_host_byte() > by only translating good status values into BLK_STS_OK. > > Fixes: e39a97353e53 ("scsi: core: return BLK_STS_OK for DID_OK in > __scsi_error_from_host_byte()") Reported-by: Damien Le Moal > <damien.lemoal@wdc.com> Signed-off-by: Bart Van Assche > <bart.vanassche@wdc.com> Cc: Hannes Reinecke <hare@suse.com> > Cc: Douglas Gilbert <dgilbert@interlog.com> > Cc: Damien Le Moal <damien.lemoal@wdc.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: stable@vger.kernel.org > --- > > Changes compared to v1: > - Modified __scsi_error_from_host_byte() such that it again returns > BLK_STS_OK for CONDITION MET and other result codes that represent > success. > > drivers/scsi/scsi_lib.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index 74a39db57d49..1496b34af409 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -736,7 +736,13 @@ static blk_status_t > __scsi_error_from_host_byte(struct scsi_cmnd *cmd, { > switch (host_byte(result)) { > case DID_OK: > - return BLK_STS_OK; > + /* > + * Also check the other bytes than the status byte > in result > + * to handle the case when a SCSI LLD sets result to > + * DRIVER_SENSE << 24 without setting > SAM_STAT_CHECK_CONDITION. > + */ > + return scsi_status_is_good(result) && (result & > ~0xff) == 0 ? > + BLK_STS_OK : BLK_STS_IOERR; > case DID_TRANSPORT_FAILFAST: > return BLK_STS_TRANSPORT; > case DID_TARGET_FAILURE: And a further nit-pick: the function is called __scsi_error_from_host_byte(), so it's only logical that it would only check the host_byte(). What's wrong is the _usage_ here; after calling __scsi_error_from_host_byte() we need to check if the _other_ bits of the results are non-zero to end up with a valid result. Hence I would advocate to either rename this function (__scsi_error_from_result() ?) or evaluate the remaining bits outside this function. But I would advocate for the former; otherwise the same issue will crop up again in the future. Cheers, Hannes
On Wed, Apr 04, 2018 at 10:53:55AM -0700, Bart Van Assche wrote: > + /* > + * Also check the other bytes than the status byte in result > + * to handle the case when a SCSI LLD sets result to > + * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION. > + */ > + return scsi_status_is_good(result) && (result & ~0xff) == 0 ? > + BLK_STS_OK : BLK_STS_IOERR; How about an readable version of the statement above? if (scsi_status_is_good(result) && (result & ~0xff)) return BLK_STS_OK; return BLK_STS_IOERR;
On Thu, Apr 05, 2018 at 08:43:18AM +0200, Hannes Reinecke wrote: > And a further nit-pick: the function is called > __scsi_error_from_host_byte(), so it's only logical that it would only > check the host_byte(). > What's wrong is the _usage_ here; after calling > __scsi_error_from_host_byte() we need to check if the _other_ bits of > the results are non-zero to end up with a valid result. > > Hence I would advocate to either rename this function > (__scsi_error_from_result() ?) or evaluate the remaining bits outside > this function. > > But I would advocate for the former; otherwise the same issue will crop > up again in the future. Please also drop the pointless double underscore prefix while at it, otherwise fully agreed.
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 74a39db57d49..1496b34af409 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -736,7 +736,13 @@ static blk_status_t __scsi_error_from_host_byte(struct scsi_cmnd *cmd, { switch (host_byte(result)) { case DID_OK: - return BLK_STS_OK; + /* + * Also check the other bytes than the status byte in result + * to handle the case when a SCSI LLD sets result to + * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION. + */ + return scsi_status_is_good(result) && (result & ~0xff) == 0 ? + BLK_STS_OK : BLK_STS_IOERR; case DID_TRANSPORT_FAILFAST: return BLK_STS_TRANSPORT; case DID_TARGET_FAILURE:
Commit e39a97353e53 modified __scsi_error_from_host_byte() such that that function translates DID_OK into BLK_STS_OK. However, the description of that commit is wrong: it mentions that commit 2a842acab109 introduced a bug in __scsi_error_from_host_byte() although that commit did not change the behavior of that function. Additionally, commit e39a97353e53 introduced a severe bug: it causes commands that fail with hostbyte=DID_OK and driverbyte=DRIVER_SENSE to be completed with BLK_STS_OK. Fix __scsi_error_from_host_byte() by only translating good status values into BLK_STS_OK. Fixes: e39a97353e53 ("scsi: core: return BLK_STS_OK for DID_OK in __scsi_error_from_host_byte()") Reported-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Douglas Gilbert <dgilbert@interlog.com> Cc: Damien Le Moal <damien.lemoal@wdc.com> Cc: Christoph Hellwig <hch@lst.de> Cc: stable@vger.kernel.org --- Changes compared to v1: - Modified __scsi_error_from_host_byte() such that it again returns BLK_STS_OK for CONDITION MET and other result codes that represent success. drivers/scsi/scsi_lib.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)