| Message ID | 20151006043256.GA8193@xzibit.linux.bs1.fc.nec.co.jp (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 10/06/15 13:32, Junichi Nomura wrote: > The commit 1bab0de0274f ("dm-mpath, scsi_dh: don't let dm detach device > handlers") removed reference counting of attached scsi device handler. > As a result, handler data is freed immediately via scsi_dh->detach() > in the context of scsi_remove_device() where activation request can be > still in flight. > > This patch moves scsi_dh_handler_detach() to sdev releasing function, > scsi_device_dev_release_usercontext(), at that point the device > is already in quiesced state. > > Fixes: 1bab0de0274f ("dm-mpath, scsi_dh: don't let dm detach device handlers") > Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> > Acked-by: Christoph Hellwig <hch@lst.de> Hello James, could we get this regression fix before 4.3 is released? Problem happens like this: dm-multipath sysadmin ------------------------------------------------------------------ scsi_dh_activate() [start using handler data] echo 1 > /sys/block/sdX/device/delete scsi_remove_device() scsi_dh_remove_device() scsi_dh->detach() kfree(handler data) [still using freed handler data] [finish using handler data] and can result in crash or data corruption. > --- > drivers/scsi/scsi_dh.c | 6 +++++- > drivers/scsi/scsi_priv.h | 2 ++ > drivers/scsi/scsi_sysfs.c | 2 ++ > 3 files changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/scsi_dh.c b/drivers/scsi/scsi_dh.c > index edb044a..19bf9db 100644 > --- a/drivers/scsi/scsi_dh.c > +++ b/drivers/scsi/scsi_dh.c > @@ -232,10 +232,14 @@ int scsi_dh_add_device(struct scsi_device *sdev) > return err; > } > > -void scsi_dh_remove_device(struct scsi_device *sdev) > +void scsi_dh_release_device(struct scsi_device *sdev) > { > if (sdev->handler) > scsi_dh_handler_detach(sdev); > +} > + > +void scsi_dh_remove_device(struct scsi_device *sdev) > +{ > device_remove_file(&sdev->sdev_gendev, &scsi_dh_state_attr); > } > > diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h > index 644bb73..4d01cdb 100644 > --- a/drivers/scsi/scsi_priv.h > +++ b/drivers/scsi/scsi_priv.h > @@ -173,9 +173,11 @@ extern struct async_domain scsi_sd_probe_domain; > /* scsi_dh.c */ > #ifdef CONFIG_SCSI_DH > int scsi_dh_add_device(struct scsi_device *sdev); > +void scsi_dh_release_device(struct scsi_device *sdev); > void scsi_dh_remove_device(struct scsi_device *sdev); > #else > static inline int scsi_dh_add_device(struct scsi_device *sdev) { return 0; } > +static inline void scsi_dh_release_device(struct scsi_device *sdev) { } > static inline void scsi_dh_remove_device(struct scsi_device *sdev) { } > #endif > > diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c > index b333389..dff8faf 100644 > --- a/drivers/scsi/scsi_sysfs.c > +++ b/drivers/scsi/scsi_sysfs.c > @@ -399,6 +399,8 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work) > > sdev = container_of(work, struct scsi_device, ew.work); > > + scsi_dh_release_device(sdev); > + > parent = sdev->sdev_gendev.parent; > > spin_lock_irqsave(sdev->host->host_lock, flags);
diff --git a/drivers/scsi/scsi_dh.c b/drivers/scsi/scsi_dh.c index edb044a..19bf9db 100644 --- a/drivers/scsi/scsi_dh.c +++ b/drivers/scsi/scsi_dh.c @@ -232,10 +232,14 @@ int scsi_dh_add_device(struct scsi_device *sdev) return err; } -void scsi_dh_remove_device(struct scsi_device *sdev) +void scsi_dh_release_device(struct scsi_device *sdev) { if (sdev->handler) scsi_dh_handler_detach(sdev); +} + +void scsi_dh_remove_device(struct scsi_device *sdev) +{ device_remove_file(&sdev->sdev_gendev, &scsi_dh_state_attr); } diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h index 644bb73..4d01cdb 100644 --- a/drivers/scsi/scsi_priv.h +++ b/drivers/scsi/scsi_priv.h @@ -173,9 +173,11 @@ extern struct async_domain scsi_sd_probe_domain; /* scsi_dh.c */ #ifdef CONFIG_SCSI_DH int scsi_dh_add_device(struct scsi_device *sdev); +void scsi_dh_release_device(struct scsi_device *sdev); void scsi_dh_remove_device(struct scsi_device *sdev); #else static inline int scsi_dh_add_device(struct scsi_device *sdev) { return 0; } +static inline void scsi_dh_release_device(struct scsi_device *sdev) { } static inline void scsi_dh_remove_device(struct scsi_device *sdev) { } #endif diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index b333389..dff8faf 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -399,6 +399,8 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work) sdev = container_of(work, struct scsi_device, ew.work); + scsi_dh_release_device(sdev); + parent = sdev->sdev_gendev.parent; spin_lock_irqsave(sdev->host->host_lock, flags);
The commit 1bab0de0274f ("dm-mpath, scsi_dh: don't let dm detach device handlers") removed reference counting of attached scsi device handler. As a result, handler data is freed immediately via scsi_dh->detach() in the context of scsi_remove_device() where activation request can be still in flight. This patch moves scsi_dh_handler_detach() to sdev releasing function, scsi_device_dev_release_usercontext(), at that point the device is already in quiesced state. Fixes: 1bab0de0274f ("dm-mpath, scsi_dh: don't let dm detach device handlers") Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Acked-by: Christoph Hellwig <hch@lst.de> --- drivers/scsi/scsi_dh.c | 6 +++++- drivers/scsi/scsi_priv.h | 2 ++ drivers/scsi/scsi_sysfs.c | 2 ++ 3 files changed, 9 insertions(+), 1 deletion(-)