diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2012-06-21 23:47:28 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-08-09 08:27:34 -0700 |
| commit | 8fff2f802f32cbb0ed253117cc01586762c22ae9 (patch) | |
| tree | 809e7821c4f74694f886b8d1ce29aa367832e27e /drivers/scsi/scsi_sysfs.c | |
| parent | bd9afacc545006fac0136c42783bdad0688e9165 (diff) | |
SCSI: fix hot unplug vs async scan race
commit 3b661a92e869ebe2358de8f4b3230ad84f7fce51 upstream.
The following crash results from cases where the end_device has been
removed before scsi_sysfs_add_sdev has had a chance to run.
BUG: unable to handle kernel NULL pointer dereference at 0000000000000098
IP: [<ffffffff8115e100>] sysfs_create_dir+0x32/0xb6
...
Call Trace:
[<ffffffff8125e4a8>] kobject_add_internal+0x120/0x1e3
[<ffffffff81075149>] ? trace_hardirqs_on+0xd/0xf
[<ffffffff8125e641>] kobject_add_varg+0x41/0x50
[<ffffffff8125e70b>] kobject_add+0x64/0x66
[<ffffffff8131122b>] device_add+0x12d/0x63a
[<ffffffff814b65ea>] ? _raw_spin_unlock_irqrestore+0x47/0x56
[<ffffffff8107de15>] ? module_refcount+0x89/0xa0
[<ffffffff8132f348>] scsi_sysfs_add_sdev+0x4e/0x28a
[<ffffffff8132dcbb>] do_scan_async+0x9c/0x145
...teach scsi_sysfs_add_devices() to check for deleted devices() before
trying to add them, and teach scsi_remove_target() how to remove targets
that have not been added via device_add().
Reported-by: Dariusz Majchrzak <dariusz.majchrzak@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/scsi/scsi_sysfs.c')
| -rw-r--r-- | drivers/scsi/scsi_sysfs.c | 41 |
1 files changed, 26 insertions, 15 deletions
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index e0bd3f790fc..de21547e7c4 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -962,7 +962,6 @@ static void __scsi_remove_target(struct scsi_target *starget) struct scsi_device *sdev; spin_lock_irqsave(shost->host_lock, flags); - starget->reap_ref++; restart: list_for_each_entry(sdev, &shost->__devices, siblings) { if (sdev->channel != starget->channel || @@ -976,14 +975,6 @@ static void __scsi_remove_target(struct scsi_target *starget) goto restart; } spin_unlock_irqrestore(shost->host_lock, flags); - scsi_target_reap(starget); -} - -static int __remove_child (struct device * dev, void * data) -{ - if (scsi_is_target_device(dev)) - __scsi_remove_target(to_scsi_target(dev)); - return 0; } /** @@ -996,14 +987,34 @@ static int __remove_child (struct device * dev, void * data) */ void scsi_remove_target(struct device *dev) { - if (scsi_is_target_device(dev)) { - __scsi_remove_target(to_scsi_target(dev)); - return; + struct Scsi_Host *shost = dev_to_shost(dev->parent); + struct scsi_target *starget, *found; + unsigned long flags; + + restart: + found = NULL; + spin_lock_irqsave(shost->host_lock, flags); + list_for_each_entry(starget, &shost->__targets, siblings) { + if (starget->state == STARGET_DEL) + continue; + if (starget->dev.parent == dev || &starget->dev == dev) { + found = starget; + found->reap_ref++; + break; + } } + spin_unlock_irqrestore(shost->host_lock, flags); - get_device(dev); - device_for_each_child(dev, NULL, __remove_child); - put_device(dev); + if (found) { + __scsi_remove_target(found); + scsi_target_reap(found); + /* in the case where @dev has multiple starget children, + * continue removing. + * + * FIXME: does such a case exist? + */ + goto restart; + } } EXPORT_SYMBOL(scsi_remove_target); |