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scsi_dh: fix use-after-free when removing scsi device

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The commit 1bab0de027 ("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: 1bab0de027 ("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>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
This commit is contained in:
Junichi Nomura 2015-10-06 04:32:57 +00:00 committed by James Bottomley
parent 2280521719
commit 23695e41a1
3 changed files with 9 additions and 1 deletions
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6
drivers/scsi/scsi_dh.c
View file

@ -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);
}

2
drivers/scsi/scsi_priv.h
View file

@ -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

2
drivers/scsi/scsi_sysfs.c
View file

@ -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);