This is a follow up to "scsi: Add intermediate STARGET_REMOVE state to
scsi_target_state".
Changes to v3:
* Incorporate James' suggestions for the commit messages.
* Re-add accidently dropped Reviewed-by tags.
Changes to v2:
* Reverse the order of patches as pointed out by James.
Changes to v1:
* Fix error (hit BUG_ON()) discovered by the 0-Day bot.
* Revert "scsi: fix soft lockup in scsi_remove_target() on module removal".
Johannes Thumshirn (2):
scsi: Add intermediate STARGET_REMOVE state to scsi_target_state
Revert "scsi: fix soft lockup in scsi_remove_target() on module
removal"
drivers/scsi/scsi_scan.c | 2 ++
drivers/scsi/scsi_sysfs.c | 6 +++---
include/scsi/scsi_device.h | 1 +
3 files changed, 6 insertions(+), 3 deletions(-)
--
1.8.5.6
Now that we've done a more comprehensive fix with the intermediate
target state we can remove the previous hack introduced with commit
90a88d6ef88edcfc4f644dddc7eef4ea41bccf8b.
Signed-off-by: Johannes Thumshirn <[email protected]>
Cc: [email protected]
Reviewed-by: Ewan D. Milne <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
---
drivers/scsi/scsi_sysfs.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 0df82e8..9e5f893 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1272,19 +1272,17 @@ static void __scsi_remove_target(struct scsi_target *starget)
void scsi_remove_target(struct device *dev)
{
struct Scsi_Host *shost = dev_to_shost(dev->parent);
- struct scsi_target *starget, *last_target = NULL;
+ struct scsi_target *starget;
unsigned long flags;
restart:
spin_lock_irqsave(shost->host_lock, flags);
list_for_each_entry(starget, &shost->__targets, siblings) {
if (starget->state == STARGET_DEL ||
- starget->state == STARGET_REMOVE ||
- starget == last_target)
+ starget->state == STARGET_REMOVE)
continue;
if (starget->dev.parent == dev || &starget->dev == dev) {
kref_get(&starget->reap_ref);
- last_target = starget;
starget->state = STARGET_REMOVE;
spin_unlock_irqrestore(shost->host_lock, flags);
__scsi_remove_target(starget);
--
1.8.5.6
Add intermediate STARGET_REMOVE state to scsi_target_state to avoid
running into the BUG_ON() in scsi_target_reap(). The STARGET_REMOVE
state is only valid in the path from scsi_remove_target() to
scsi_target_destroy() indicating this target is going to be removed.
This re-fixes the problem introduced in commits
bc3f02a795d3b4faa99d37390174be2a75d091bd and
40998193560dab6c3ce8d25f4fa58a23e252ef38 in a more comprehensive way.
Signed-off-by: Johannes Thumshirn <[email protected]>
Fixes: 40998193560dab6c3ce8d25f4fa58a23e252ef38
Cc: [email protected]
Reviewed-by: Ewan D. Milne <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Reviewed-by: James Bottomley <[email protected]>
---
drivers/scsi/scsi_scan.c | 2 ++
drivers/scsi/scsi_sysfs.c | 2 ++
include/scsi/scsi_device.h | 1 +
3 files changed, 5 insertions(+)
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 6a82066..63b8bca 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -315,6 +315,8 @@ static void scsi_target_destroy(struct scsi_target *starget)
struct Scsi_Host *shost = dev_to_shost(dev->parent);
unsigned long flags;
+ BUG_ON(starget->state != STARGET_REMOVE &&
+ starget->state != STARGET_CREATED);
starget->state = STARGET_DEL;
transport_destroy_device(dev);
spin_lock_irqsave(shost->host_lock, flags);
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 00bc721..0df82e8 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1279,11 +1279,13 @@ restart:
spin_lock_irqsave(shost->host_lock, flags);
list_for_each_entry(starget, &shost->__targets, siblings) {
if (starget->state == STARGET_DEL ||
+ starget->state == STARGET_REMOVE ||
starget == last_target)
continue;
if (starget->dev.parent == dev || &starget->dev == dev) {
kref_get(&starget->reap_ref);
last_target = starget;
+ starget->state = STARGET_REMOVE;
spin_unlock_irqrestore(shost->host_lock, flags);
__scsi_remove_target(starget);
scsi_target_reap(starget);
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index f63a167..2bffaa6 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -240,6 +240,7 @@ scmd_printk(const char *, const struct scsi_cmnd *, const char *, ...);
enum scsi_target_state {
STARGET_CREATED = 1,
STARGET_RUNNING,
+ STARGET_REMOVE,
STARGET_DEL,
};
--
1.8.5.6
>>>>> "Johannes" == Johannes Thumshirn <[email protected]> writes:
Johannes> This is a follow up to "scsi: Add intermediate STARGET_REMOVE
Johannes> state to scsi_target_state".
James suggested we should let this incubate before hitting stable.
Dropped v3 from 4.6/scsi-fixes and applied v4 to 4.7/scsi-queue.
Thanks!
--
Martin K. Petersen Oracle Linux Engineering
On 2016-04-05 13:18, Martin K. Petersen wrote:
>>>>>> "Johannes" == Johannes Thumshirn <[email protected]> writes:
>
> Johannes> This is a follow up to "scsi: Add intermediate STARGET_REMOVE
> Johannes> state to scsi_target_state".
>
> James suggested we should let this incubate before hitting stable.
>
> Dropped v3 from 4.6/scsi-fixes and applied v4 to 4.7/scsi-queue.
Sounds good to me.
Hi,
On Tue, Apr 5, 2016 at 5:50 PM, Johannes Thumshirn <[email protected]> wrote:
> Add intermediate STARGET_REMOVE state to scsi_target_state to avoid
> running into the BUG_ON() in scsi_target_reap(). The STARGET_REMOVE
> state is only valid in the path from scsi_remove_target() to
> scsi_target_destroy() indicating this target is going to be removed.
>
> This re-fixes the problem introduced in commits
> bc3f02a795d3b4faa99d37390174be2a75d091bd and
> 40998193560dab6c3ce8d25f4fa58a23e252ef38 in a more comprehensive way.
>
> Signed-off-by: Johannes Thumshirn <[email protected]>
> Fixes: 40998193560dab6c3ce8d25f4fa58a23e252ef38
> Cc: [email protected]
> Reviewed-by: Ewan D. Milne <[email protected]>
> Reviewed-by: Hannes Reinecke <[email protected]>
> Reviewed-by: James Bottomley <[email protected]>
> ---
> drivers/scsi/scsi_scan.c | 2 ++
> drivers/scsi/scsi_sysfs.c | 2 ++
> include/scsi/scsi_device.h | 1 +
> 3 files changed, 5 insertions(+)
>
> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> index 6a82066..63b8bca 100644
> --- a/drivers/scsi/scsi_scan.c
> +++ b/drivers/scsi/scsi_scan.c
> @@ -315,6 +315,8 @@ static void scsi_target_destroy(struct scsi_target *starget)
> struct Scsi_Host *shost = dev_to_shost(dev->parent);
> unsigned long flags;
>
> + BUG_ON(starget->state != STARGET_REMOVE &&
> + starget->state != STARGET_CREATED);
#modprobe scsi_debug
#modprobe -r scsi_debug
always triggers this BUG_ON in linux-next-20160411
printk says starget->state is _RUNNING
> starget->state = STARGET_DEL;
> transport_destroy_device(dev);
> spin_lock_irqsave(shost->host_lock, flags);
> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
> index 00bc721..0df82e8 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -1279,11 +1279,13 @@ restart:
> spin_lock_irqsave(shost->host_lock, flags);
> list_for_each_entry(starget, &shost->__targets, siblings) {
> if (starget->state == STARGET_DEL ||
> + starget->state == STARGET_REMOVE ||
> starget == last_target)
> continue;
> if (starget->dev.parent == dev || &starget->dev == dev) {
> kref_get(&starget->reap_ref);
> last_target = starget;
> + starget->state = STARGET_REMOVE;
> spin_unlock_irqrestore(shost->host_lock, flags);
> __scsi_remove_target(starget);
> scsi_target_reap(starget);
> diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
> index f63a167..2bffaa6 100644
> --- a/include/scsi/scsi_device.h
> +++ b/include/scsi/scsi_device.h
> @@ -240,6 +240,7 @@ scmd_printk(const char *, const struct scsi_cmnd *, const char *, ...);
> enum scsi_target_state {
> STARGET_CREATED = 1,
> STARGET_RUNNING,
> + STARGET_REMOVE,
> STARGET_DEL,
> };
>
> --
> 1.8.5.6
>
How about this?
drivers/scsi/scsi_scan: mark STARGET_REMOVE state before destroy
Signed-off-by: Xiong Zhou <[email protected]>
---
drivers/scsi/scsi_scan.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 27df7e7..21092e5 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -395,6 +395,8 @@ static void scsi_target_reap_ref_release(struct kref *kref)
transport_remove_device(&starget->dev);
device_del(&starget->dev);
}
+
+ starget->state = STARGET_REMOVE;
scsi_target_destroy(starget);
}
@@ -465,6 +467,7 @@ static struct scsi_target
*scsi_alloc_target(struct device *parent,
dev_printk(KERN_ERR, dev, "target allocation failed, error %d\n", error);
/* don't want scsi_target_reap to do the final
* put because it will be under the host lock */
+ starget->state = STARGET_REMOVE;
scsi_target_destroy(starget);
return NULL;
}
--
1.8.3.1
On Tue, Apr 5, 2016 at 5:50 PM, Johannes Thumshirn <[email protected]> wrote:
> Add intermediate STARGET_REMOVE state to scsi_target_state to avoid
> running into the BUG_ON() in scsi_target_reap(). The STARGET_REMOVE
> state is only valid in the path from scsi_remove_target() to
> scsi_target_destroy() indicating this target is going to be removed.
>
> This re-fixes the problem introduced in commits
> bc3f02a795d3b4faa99d37390174be2a75d091bd and
> 40998193560dab6c3ce8d25f4fa58a23e252ef38 in a more comprehensive way.
>
> Signed-off-by: Johannes Thumshirn <[email protected]>
> Fixes: 40998193560dab6c3ce8d25f4fa58a23e252ef38
> Cc: [email protected]
> Reviewed-by: Ewan D. Milne <[email protected]>
> Reviewed-by: Hannes Reinecke <[email protected]>
> Reviewed-by: James Bottomley <[email protected]>
> ---
> drivers/scsi/scsi_scan.c | 2 ++
> drivers/scsi/scsi_sysfs.c | 2 ++
> include/scsi/scsi_device.h | 1 +
> 3 files changed, 5 insertions(+)
>
> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> index 6a82066..63b8bca 100644
> --- a/drivers/scsi/scsi_scan.c
> +++ b/drivers/scsi/scsi_scan.c
> @@ -315,6 +315,8 @@ static void scsi_target_destroy(struct scsi_target *starget)
> struct Scsi_Host *shost = dev_to_shost(dev->parent);
> unsigned long flags;
>
> + BUG_ON(starget->state != STARGET_REMOVE &&
> + starget->state != STARGET_CREATED);
> starget->state = STARGET_DEL;
> transport_destroy_device(dev);
> spin_lock_irqsave(shost->host_lock, flags);
> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
> index 00bc721..0df82e8 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -1279,11 +1279,13 @@ restart:
> spin_lock_irqsave(shost->host_lock, flags);
> list_for_each_entry(starget, &shost->__targets, siblings) {
> if (starget->state == STARGET_DEL ||
> + starget->state == STARGET_REMOVE ||
> starget == last_target)
> continue;
> if (starget->dev.parent == dev || &starget->dev == dev) {
> kref_get(&starget->reap_ref);
> last_target = starget;
> + starget->state = STARGET_REMOVE;
> spin_unlock_irqrestore(shost->host_lock, flags);
> __scsi_remove_target(starget);
> scsi_target_reap(starget);
> diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
> index f63a167..2bffaa6 100644
> --- a/include/scsi/scsi_device.h
> +++ b/include/scsi/scsi_device.h
> @@ -240,6 +240,7 @@ scmd_printk(const char *, const struct scsi_cmnd *, const char *, ...);
> enum scsi_target_state {
> STARGET_CREATED = 1,
> STARGET_RUNNING,
> + STARGET_REMOVE,
> STARGET_DEL,
> };
>
> --
> 1.8.5.6
>
Hi Xiong
Sorry for the late reply
On Dienstag, 12. April 2016 21:01:53 CEST Xiong Zhou wrote:
> How about this?
>
> drivers/scsi/scsi_scan: mark STARGET_REMOVE state before destroy
>
> Signed-off-by: Xiong Zhou <[email protected]>
> ---
> drivers/scsi/scsi_scan.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> index 27df7e7..21092e5 100644
> --- a/drivers/scsi/scsi_scan.c
> +++ b/drivers/scsi/scsi_scan.c
> @@ -395,6 +395,8 @@ static void scsi_target_reap_ref_release(struct kref *kref)
> transport_remove_device(&starget->dev);
> device_del(&starget->dev);
> }
> +
> + starget->state = STARGET_REMOVE;
> scsi_target_destroy(starget);
> }
The only scsi_target_reap_ref_release() caller is scsi_target_reap_ref_put(),
which in turn is only called by scsi_target_reap(). scsi_target_reap()'s only
callers are scsi_remove_target()/__scsi_remove_target(), which set the
STARGET_REMOVE state and
__scsi_add_device()
scsi_get_host_dev()
__scsi_scan_target()
Which I'm currently investiganting (in parallel to reproducing the bug).
>
> @@ -465,6 +467,7 @@ static struct scsi_target
> *scsi_alloc_target(struct device *parent,
> dev_printk(KERN_ERR, dev, "target allocation failed, error %d\n", error);
> /* don't want scsi_target_reap to do the final
> * put because it will be under the host lock */
> + starget->state = STARGET_REMOVE;
> scsi_target_destroy(starget);
> return NULL;
> }
Here starget->state is STARGET_CREATED and the assertion is already aware of
this state transitoin. IOTW this /shouldn't/ be needed.
--
Johannes Thumshirn Storage
[email protected] +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N?rnberg
GF: Felix Imend?rffer, Jane Smithard, Graham Norton
HRB 21284 (AG N?rnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
On Wed, Apr 13, 2016 at 4:19 PM, Johannes Thumshirn <[email protected]> wrote:
> Hi Xiong
> Sorry for the late reply
>
> On Dienstag, 12. April 2016 21:01:53 CEST Xiong Zhou wrote:
>> How about this?
>>
>> drivers/scsi/scsi_scan: mark STARGET_REMOVE state before destroy
>>
>> Signed-off-by: Xiong Zhou <[email protected]>
>> ---
>> drivers/scsi/scsi_scan.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
>> index 27df7e7..21092e5 100644
>> --- a/drivers/scsi/scsi_scan.c
>> +++ b/drivers/scsi/scsi_scan.c
>> @@ -395,6 +395,8 @@ static void scsi_target_reap_ref_release(struct kref *kref)
>> transport_remove_device(&starget->dev);
>> device_del(&starget->dev);
>> }
>> +
>> + starget->state = STARGET_REMOVE;
>> scsi_target_destroy(starget);
>> }
>
> The only scsi_target_reap_ref_release() caller is scsi_target_reap_ref_put(),
> which in turn is only called by scsi_target_reap(). scsi_target_reap()'s only
> callers are scsi_remove_target()/__scsi_remove_target(), which set the
> STARGET_REMOVE state and
>
> __scsi_add_device()
> scsi_get_host_dev()
> __scsi_scan_target()
>
> Which I'm currently investiganting (in parallel to reproducing the bug).
Thanks !
--
Xiong
>
>>
>> @@ -465,6 +467,7 @@ static struct scsi_target
>> *scsi_alloc_target(struct device *parent,
>> dev_printk(KERN_ERR, dev, "target allocation failed, error %d\n", error);
>> /* don't want scsi_target_reap to do the final
>> * put because it will be under the host lock */
>> + starget->state = STARGET_REMOVE;
>> scsi_target_destroy(starget);
>> return NULL;
>> }
>
> Here starget->state is STARGET_CREATED and the assertion is already aware of
> this state transitoin. IOTW this /shouldn't/ be needed.
>
>
> --
> Johannes Thumshirn Storage
> [email protected] +49 911 74053 689
> SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
> GF: Felix Imendörffer, Jane Smithard, Graham Norton
> HRB 21284 (AG Nürnberg)
> Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
>