Re: [PATCH] iscsi: Fix a sleep-in-atomic bug

2017-06-01 Thread Nicholas A. Bellinger 
On Fri, 2017-06-02 at 09:13 +0800, Jia-Ju Bai wrote:
> On 06/01/2017 02:21 PM, Nicholas A. Bellinger wrote:
> > Hi Jia-Ju,
> >
> > On Wed, 2017-05-31 at 11:26 +0800, Jia-Ju Bai wrote:
> >> The driver may sleep under a spin lock, and the function call path is:
> >> iscsit_tpg_enable_portal_group (acquire the lock by spin_lock)
> >>iscsi_update_param_value
> >>  kstrdup(GFP_KERNEL) -->  may sleep
> >>
> >> To fix it, the "GFP_KERNEL" is replaced with "GFP_ATOMIC".
> >>
> >> Signed-off-by: Jia-Ju Bai
> >> ---
> >>   drivers/target/iscsi/iscsi_target_parameters.c |2 +-
> >>   1 file changed, 1 insertion(+), 1 deletion(-)
> > Btw, the use of tpg->tpg_state_lock in iscsit_tpg_enable_portal_group()
> > while checking existing state and calling iscsi_update_param_value() is
> > not necessary, since lio_target_tpg_enable_store() is already holding
> > iscsit_get_tpg() ->  tpg->tpg_access_lock.
> >
> > How about the following instead to only take tpg->tpg_state_lock when
> > updating tpg->tpg_state instead..?
> >
> > diff --git a/drivers/target/iscsi/iscsi_target_tpg.c 
> > b/drivers/target/iscsi/iscsi_target_tpg.c
> > index 2e7e08d..abaabba 100644
> > --- a/drivers/target/iscsi/iscsi_target_tpg.c
> > +++ b/drivers/target/iscsi/iscsi_target_tpg.c
> > @@ -311,11 +311,9 @@ int iscsit_tpg_enable_portal_group(struct 
> > iscsi_portal_group *tpg)
> >  struct iscsi_tiqn *tiqn = tpg->tpg_tiqn;
> >  int ret;
> >
> > -   spin_lock(>tpg_state_lock);
> >  if (tpg->tpg_state == TPG_STATE_ACTIVE) {
> >  pr_err("iSCSI target portal group: %hu is already"
> >  " active, ignoring request.\n", tpg->tpgt);
> > -   spin_unlock(>tpg_state_lock);
> >  return -EINVAL;
> >  }
> >  /*
> > @@ -324,10 +322,8 @@ int iscsit_tpg_enable_portal_group(struct 
> > iscsi_portal_group *tpg)
> >   * is enforced (as per default), and remove the NONE option.
> >   */
> >  param = iscsi_find_param_from_key(AUTHMETHOD, tpg->param_list);
> > -   if (!param) {
> > -   spin_unlock(>tpg_state_lock);
> > +   if (!param)
> >  return -EINVAL;
> > -   }
> >
> >  if (tpg->tpg_attrib.authentication) {
> >  if (!strcmp(param->value, NONE)) {
> > @@ -341,6 +337,7 @@ int iscsit_tpg_enable_portal_group(struct 
> > iscsi_portal_group *tpg)
> >  goto err;
> >  }
> >
> > +   spin_lock(>tpg_state_lock);
> >  tpg->tpg_state = TPG_STATE_ACTIVE;
> >  spin_unlock(>tpg_state_lock);
> >
> > @@ -353,7 +350,6 @@ int iscsit_tpg_enable_portal_group(struct 
> > iscsi_portal_group *tpg)
> >  return 0;
> >
> >   err:
> > -   spin_unlock(>tpg_state_lock);
> >  return ret;
> >   }
> >
> I think it is fine to me.
> 
> Thanks,
> Jia-Ju Bai

Applied with your Reported-by and Reviewed-by.

Thanks!

Re: [PATCH] iscsi: Fix a sleep-in-atomic bug

2017-06-01 Thread Jia-Ju Bai 

On 06/01/2017 02:21 PM, Nicholas A. Bellinger wrote:

Hi Jia-Ju,

On Wed, 2017-05-31 at 11:26 +0800, Jia-Ju Bai wrote:

The driver may sleep under a spin lock, and the function call path is:
iscsit_tpg_enable_portal_group (acquire the lock by spin_lock)
   iscsi_update_param_value
 kstrdup(GFP_KERNEL) -->  may sleep

To fix it, the "GFP_KERNEL" is replaced with "GFP_ATOMIC".

Signed-off-by: Jia-Ju Bai
---
  drivers/target/iscsi/iscsi_target_parameters.c |2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

Btw, the use of tpg->tpg_state_lock in iscsit_tpg_enable_portal_group()
while checking existing state and calling iscsi_update_param_value() is
not necessary, since lio_target_tpg_enable_store() is already holding
iscsit_get_tpg() ->  tpg->tpg_access_lock.

How about the following instead to only take tpg->tpg_state_lock when
updating tpg->tpg_state instead..?

diff --git a/drivers/target/iscsi/iscsi_target_tpg.c 
b/drivers/target/iscsi/iscsi_target_tpg.c
index 2e7e08d..abaabba 100644
--- a/drivers/target/iscsi/iscsi_target_tpg.c
+++ b/drivers/target/iscsi/iscsi_target_tpg.c
@@ -311,11 +311,9 @@ int iscsit_tpg_enable_portal_group(struct 
iscsi_portal_group *tpg)
 struct iscsi_tiqn *tiqn = tpg->tpg_tiqn;
 int ret;

-   spin_lock(>tpg_state_lock);
 if (tpg->tpg_state == TPG_STATE_ACTIVE) {
 pr_err("iSCSI target portal group: %hu is already"
 " active, ignoring request.\n", tpg->tpgt);
-   spin_unlock(>tpg_state_lock);
 return -EINVAL;
 }
 /*
@@ -324,10 +322,8 @@ int iscsit_tpg_enable_portal_group(struct 
iscsi_portal_group *tpg)
  * is enforced (as per default), and remove the NONE option.
  */
 param = iscsi_find_param_from_key(AUTHMETHOD, tpg->param_list);
-   if (!param) {
-   spin_unlock(>tpg_state_lock);
+   if (!param)
 return -EINVAL;
-   }

 if (tpg->tpg_attrib.authentication) {
 if (!strcmp(param->value, NONE)) {
@@ -341,6 +337,7 @@ int iscsit_tpg_enable_portal_group(struct 
iscsi_portal_group *tpg)
 goto err;
 }

+   spin_lock(>tpg_state_lock);
 tpg->tpg_state = TPG_STATE_ACTIVE;
 spin_unlock(>tpg_state_lock);

@@ -353,7 +350,6 @@ int iscsit_tpg_enable_portal_group(struct 
iscsi_portal_group *tpg)
 return 0;

  err:
-   spin_unlock(>tpg_state_lock);
 return ret;
  }


I think it is fine to me.

Thanks,
Jia-Ju Bai

Re: [PATCH] iscsi: Fix a sleep-in-atomic bug

2017-06-01 Thread Nicholas A. Bellinger 
Hi Jia-Ju,

On Wed, 2017-05-31 at 11:26 +0800, Jia-Ju Bai wrote:
> The driver may sleep under a spin lock, and the function call path is:
> iscsit_tpg_enable_portal_group (acquire the lock by spin_lock)
>   iscsi_update_param_value
> kstrdup(GFP_KERNEL) --> may sleep
> 
> To fix it, the "GFP_KERNEL" is replaced with "GFP_ATOMIC".
> 
> Signed-off-by: Jia-Ju Bai 
> ---
>  drivers/target/iscsi/iscsi_target_parameters.c |2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Btw, the use of tpg->tpg_state_lock in iscsit_tpg_enable_portal_group()
while checking existing state and calling iscsi_update_param_value() is
not necessary, since lio_target_tpg_enable_store() is already holding
iscsit_get_tpg() -> tpg->tpg_access_lock.

How about the following instead to only take tpg->tpg_state_lock when
updating tpg->tpg_state instead..?

diff --git a/drivers/target/iscsi/iscsi_target_tpg.c 
b/drivers/target/iscsi/iscsi_target_tpg.c
index 2e7e08d..abaabba 100644
--- a/drivers/target/iscsi/iscsi_target_tpg.c
+++ b/drivers/target/iscsi/iscsi_target_tpg.c
@@ -311,11 +311,9 @@ int iscsit_tpg_enable_portal_group(struct 
iscsi_portal_group *tpg)
struct iscsi_tiqn *tiqn = tpg->tpg_tiqn;
int ret;
 
-   spin_lock(>tpg_state_lock);
if (tpg->tpg_state == TPG_STATE_ACTIVE) {
pr_err("iSCSI target portal group: %hu is already"
" active, ignoring request.\n", tpg->tpgt);
-   spin_unlock(>tpg_state_lock);
return -EINVAL;
}
/*
@@ -324,10 +322,8 @@ int iscsit_tpg_enable_portal_group(struct 
iscsi_portal_group *tpg)
 * is enforced (as per default), and remove the NONE option.
 */
param = iscsi_find_param_from_key(AUTHMETHOD, tpg->param_list);
-   if (!param) {
-   spin_unlock(>tpg_state_lock);
+   if (!param)
return -EINVAL;
-   }
 
if (tpg->tpg_attrib.authentication) {
if (!strcmp(param->value, NONE)) {
@@ -341,6 +337,7 @@ int iscsit_tpg_enable_portal_group(struct 
iscsi_portal_group *tpg)
goto err;
}
 
+   spin_lock(>tpg_state_lock);
tpg->tpg_state = TPG_STATE_ACTIVE;
spin_unlock(>tpg_state_lock);
 
@@ -353,7 +350,6 @@ int iscsit_tpg_enable_portal_group(struct 
iscsi_portal_group *tpg)
return 0;
 
 err:
-   spin_unlock(>tpg_state_lock);
return ret;
 }

[PATCH] iscsi: Fix a sleep-in-atomic bug

2017-05-30 Thread Jia-Ju Bai 
The driver may sleep under a spin lock, and the function call path is:
iscsit_tpg_enable_portal_group (acquire the lock by spin_lock)
  iscsi_update_param_value
kstrdup(GFP_KERNEL) --> may sleep

To fix it, the "GFP_KERNEL" is replaced with "GFP_ATOMIC".

Signed-off-by: Jia-Ju Bai 
---
 drivers/target/iscsi/iscsi_target_parameters.c |2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/target/iscsi/iscsi_target_parameters.c 
b/drivers/target/iscsi/iscsi_target_parameters.c
index fce6276..8768916 100644
--- a/drivers/target/iscsi/iscsi_target_parameters.c
+++ b/drivers/target/iscsi/iscsi_target_parameters.c
@@ -702,7 +702,7 @@ int iscsi_update_param_value(struct iscsi_param *param, 
char *value)
 {
kfree(param->value);
 
-   param->value = kstrdup(value, GFP_KERNEL);
+   param->value = kstrdup(value, GFP_ATOMIC);
if (!param->value) {
pr_err("Unable to allocate memory for value.\n");
return -ENOMEM;
-- 
1.7.9.5