[PATCH 1/2] pci: Convert to use built-in RCU list checking

[PATCH 1/2] pci: Convert to use built-in RCU list checking

[Joel Fernandes (Google)]

CONFIG_PROVE_RCU_LIST requires list_for_each_entry_rcu() to pass a
lockdep expression if using srcu or locking for protection. It can only
check regular RCU protection, all other protection needs to be passed as
lockdep expression.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
 drivers/pci/controller/vmd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index 4575e0c6dc4b..127631d0c6da 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -718,7 +718,8 @@ static irqreturn_t vmd_irq(int irq, void *data)
 	int idx;
 
 	idx = srcu_read_lock(&irqs->srcu);
-	list_for_each_entry_rcu(vmdirq, &irqs->irq_list, node)
+	list_for_each_entry_rcu(vmdirq, &irqs->irq_list, node,
+				srcu_read_lock_held(&irqs->srcu))
 		generic_handle_irq(vmdirq->virq);
 	srcu_read_unlock(&irqs->srcu, idx);
 
-- 
2.23.0.187.g17f5b7556c-goog

[PATCH 2/2] ipc/sem: Convert to use built-in RCU list checking

[Joel Fernandes (Google)]

CONFIG_PROVE_RCU_LIST requires list_for_each_entry_rcu() to pass a
lockdep expression if using srcu or locking for protection. It can only
check regular RCU protection, all other protection needs to be passed as
lockdep expression.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
 ipc/sem.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/ipc/sem.c b/ipc/sem.c
index 7da4504bcc7c..ec97a7072413 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -1852,7 +1852,8 @@ static struct sem_undo *__lookup_undo(struct sem_undo_list *ulp, int semid)
 {
 	struct sem_undo *un;
 
-	list_for_each_entry_rcu(un, &ulp->list_proc, list_proc) {
+	list_for_each_entry_rcu(un, &ulp->list_proc, list_proc,
+				spin_is_locked(&ulp->lock)) {
 		if (un->semid == semid)
 			return un;
 	}
-- 
2.23.0.187.g17f5b7556c-goog

Re: [PATCH 1/2] pci: Convert to use built-in RCU list checking

[kbuild test robot]

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Hi "Joel,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[cannot apply to v5.3-rc7 next-20190903]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Joel-Fernandes-Google/pci-Convert-to-use-built-in-RCU-list-checking/20190901-211013
config: x86_64-rhel-7.6 (attached as .config)
compiler: gcc-7 (Debian 7.4.0-11) 7.4.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All error/warnings (new ones prefixed by >>):

   drivers/pci/controller/vmd.c: In function 'vmd_irq':
>> drivers/pci/controller/vmd.c:722:37: error: macro "list_for_each_entry_rcu" passed 4 arguments, but takes just 3
        srcu_read_lock_held(&irqs->srcu))
                                        ^
>> drivers/pci/controller/vmd.c:721:2: error: unknown type name 'list_for_each_entry_rcu'
     list_for_each_entry_rcu(vmdirq, &irqs->irq_list, node,
     ^~~~~~~~~~~~~~~~~~~~~~~
>> drivers/pci/controller/vmd.c:723:28: error: expected ')' before '->' token
      generic_handle_irq(vmdirq->virq);
                               ^~
>> drivers/pci/controller/vmd.c:721:2: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
     list_for_each_entry_rcu(vmdirq, &irqs->irq_list, node,
     ^~~~~~~~~~~~~~~~~~~~~~~
   drivers/pci/controller/vmd.c:717:18: warning: unused variable 'vmdirq' [-Wunused-variable]
     struct vmd_irq *vmdirq;
                     ^~~~~~

vim +/list_for_each_entry_rcu +722 drivers/pci/controller/vmd.c

   713	
   714	static irqreturn_t vmd_irq(int irq, void *data)
   715	{
   716		struct vmd_irq_list *irqs = data;
   717		struct vmd_irq *vmdirq;
   718		int idx;
   719	
   720		idx = srcu_read_lock(&irqs->srcu);
 > 721		list_for_each_entry_rcu(vmdirq, &irqs->irq_list, node,
 > 722					srcu_read_lock_held(&irqs->srcu))
 > 723			generic_handle_irq(vmdirq->virq);
   724		srcu_read_unlock(&irqs->srcu, idx);
   725	
   726		return IRQ_HANDLED;
   727	}
   728	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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Re: [PATCH 1/2] pci: Convert to use built-in RCU list checking

[Joel Fernandes]

On Wed, Sep 04, 2019 at 12:06:43PM +0800, kbuild test robot wrote:
> Hi "Joel,
> 
> Thank you for the patch! Yet something to improve:
> 
> [auto build test ERROR on linus/master]
> [cannot apply to v5.3-rc7 next-20190903]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
> 
> url:    https://github.com/0day-ci/linux/commits/Joel-Fernandes-Google/pci-Convert-to-use-built-in-RCU-list-checking/20190901-211013
> config: x86_64-rhel-7.6 (attached as .config)
> compiler: gcc-7 (Debian 7.4.0-11) 7.4.0
> reproduce:
>         # save the attached .config to linux build tree
>         make ARCH=x86_64 

This error seems bogus. I pulled -next and applied this patch and it builds
fine. I am not sure what is wrong with the 0day tree, and the above 0day link
is also dead.

What's going on with 0day ?!

thanks,

 - Joel

> 
> If you fix the issue, kindly add following tag
> Reported-by: kbuild test robot <lkp@intel.com>
> 
> All error/warnings (new ones prefixed by >>):
> 
>    drivers/pci/controller/vmd.c: In function 'vmd_irq':
> >> drivers/pci/controller/vmd.c:722:37: error: macro "list_for_each_entry_rcu" passed 4 arguments, but takes just 3
>         srcu_read_lock_held(&irqs->srcu))
>                                         ^
> >> drivers/pci/controller/vmd.c:721:2: error: unknown type name 'list_for_each_entry_rcu'
>      list_for_each_entry_rcu(vmdirq, &irqs->irq_list, node,
>      ^~~~~~~~~~~~~~~~~~~~~~~
> >> drivers/pci/controller/vmd.c:723:28: error: expected ')' before '->' token
>       generic_handle_irq(vmdirq->virq);
>                                ^~
> >> drivers/pci/controller/vmd.c:721:2: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
>      list_for_each_entry_rcu(vmdirq, &irqs->irq_list, node,
>      ^~~~~~~~~~~~~~~~~~~~~~~
>    drivers/pci/controller/vmd.c:717:18: warning: unused variable 'vmdirq' [-Wunused-variable]
>      struct vmd_irq *vmdirq;
>                      ^~~~~~
> 
> vim +/list_for_each_entry_rcu +722 drivers/pci/controller/vmd.c
> 
>    713	
>    714	static irqreturn_t vmd_irq(int irq, void *data)
>    715	{
>    716		struct vmd_irq_list *irqs = data;
>    717		struct vmd_irq *vmdirq;
>    718		int idx;
>    719	
>    720		idx = srcu_read_lock(&irqs->srcu);
>  > 721		list_for_each_entry_rcu(vmdirq, &irqs->irq_list, node,
>  > 722					srcu_read_lock_held(&irqs->srcu))
>  > 723			generic_handle_irq(vmdirq->virq);
>    724		srcu_read_unlock(&irqs->srcu, idx);
>    725	
>    726		return IRQ_HANDLED;
>    727	}
>    728	
> 
> ---
> 0-DAY kernel test infrastructure                Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

Re: [PATCH 2/2] ipc/sem: Convert to use built-in RCU list checking

[kbuild test robot]

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Hi "Joel,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[cannot apply to v5.3-rc7 next-20190903]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Joel-Fernandes-Google/pci-Convert-to-use-built-in-RCU-list-checking/20190901-211013
config: x86_64-rhel-7.6 (attached as .config)
compiler: gcc-7 (Debian 7.4.0-11) 7.4.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All error/warnings (new ones prefixed by >>):

   ipc/sem.c: In function '__lookup_undo':
>> ipc/sem.c:1856:31: error: macro "list_for_each_entry_rcu" passed 4 arguments, but takes just 3
        spin_is_locked(&ulp->lock)) {
                                  ^
>> ipc/sem.c:1855:2: error: 'list_for_each_entry_rcu' undeclared (first use in this function); did you mean 'class_for_each_device'?
     list_for_each_entry_rcu(un, &ulp->list_proc, list_proc,
     ^~~~~~~~~~~~~~~~~~~~~~~
     class_for_each_device
   ipc/sem.c:1855:2: note: each undeclared identifier is reported only once for each function it appears in
>> ipc/sem.c:1856:33: error: expected ';' before '{' token
        spin_is_locked(&ulp->lock)) {
                                    ^
   ipc/sem.c:1853:19: warning: unused variable 'un' [-Wunused-variable]
     struct sem_undo *un;
                      ^~
>> ipc/sem.c:1861:1: warning: no return statement in function returning non-void [-Wreturn-type]
    }
    ^

vim +/list_for_each_entry_rcu +1856 ipc/sem.c

  1850	
  1851	static struct sem_undo *__lookup_undo(struct sem_undo_list *ulp, int semid)
  1852	{
  1853		struct sem_undo *un;
  1854	
> 1855		list_for_each_entry_rcu(un, &ulp->list_proc, list_proc,
> 1856					spin_is_locked(&ulp->lock)) {
  1857			if (un->semid == semid)
  1858				return un;
  1859		}
  1860		return NULL;
> 1861	}
  1862	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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Re: [PATCH 1/2] pci: Convert to use built-in RCU list checking

[Andy Shevchenko]

On Wed, Sep 4, 2019 at 8:07 AM Joel Fernandes <joel@joelfernandes.org> wrote:
>
> On Wed, Sep 04, 2019 at 12:06:43PM +0800, kbuild test robot wrote:
> > Hi "Joel,
> >
> > Thank you for the patch! Yet something to improve:
> >
> > [auto build test ERROR on linus/master]
> > [cannot apply to v5.3-rc7 next-20190903]
> > [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
> >
> > url:    https://github.com/0day-ci/linux/commits/Joel-Fernandes-Google/pci-Convert-to-use-built-in-RCU-list-checking/20190901-211013
> > config: x86_64-rhel-7.6 (attached as .config)
> > compiler: gcc-7 (Debian 7.4.0-11) 7.4.0
> > reproduce:
> >         # save the attached .config to linux build tree
> >         make ARCH=x86_64
>
> This error seems bogus. I pulled -next and applied this patch and it builds
> fine. I am not sure what is wrong with the 0day tree, and the above 0day link
> is also dead.
>
> What's going on with 0day ?!

I would rather to add Depends-on: ... tag to your patch if the
dependency is going thru another tree at the same cycle.
kbuildbot absolutely correct here.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 1/2] pci: Convert to use built-in RCU list checking

[Joel Fernandes]

On Wed, Sep 4, 2019 at 1:13 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Wed, Sep 4, 2019 at 8:07 AM Joel Fernandes <joel@joelfernandes.org> wrote:
> >
> > On Wed, Sep 04, 2019 at 12:06:43PM +0800, kbuild test robot wrote:
> > > Hi "Joel,
> > >
> > > Thank you for the patch! Yet something to improve:
> > >
> > > [auto build test ERROR on linus/master]
> > > [cannot apply to v5.3-rc7 next-20190903]
> > > [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
> > >
> > > url:    https://github.com/0day-ci/linux/commits/Joel-Fernandes-Google/pci-Convert-to-use-built-in-RCU-list-checking/20190901-211013
> > > config: x86_64-rhel-7.6 (attached as .config)
> > > compiler: gcc-7 (Debian 7.4.0-11) 7.4.0
> > > reproduce:
> > >         # save the attached .config to linux build tree
> > >         make ARCH=x86_64
> >
> > This error seems bogus. I pulled -next and applied this patch and it builds
> > fine. I am not sure what is wrong with the 0day tree, and the above 0day link
> > is also dead.
> >
> > What's going on with 0day ?!
>
> I would rather to add Depends-on: ... tag to your patch if the
> dependency is going thru another tree at the same cycle.
> kbuildbot absolutely correct here.

The dependency is already in -next and I pulled it and applied the
patch. It is testing -next right?

thanks,

 - Joel

Re: [PATCH 1/2] pci: Convert to use built-in RCU list checking

[Andy Shevchenko]

On Wed, Sep 4, 2019 at 9:01 PM Joel Fernandes <joel@joelfernandes.org> wrote:
> On Wed, Sep 4, 2019 at 1:13 PM Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
> > On Wed, Sep 4, 2019 at 8:07 AM Joel Fernandes <joel@joelfernandes.org> wrote:
> > > On Wed, Sep 04, 2019 at 12:06:43PM +0800, kbuild test robot wrote:

> > > > [auto build test ERROR on linus/master]

^^^ (1)

> > > > [cannot apply to v5.3-rc7 next-20190903]

^^^ (2)


> The dependency is already in -next and I pulled it and applied the
> patch.

This is a problem. You must provide dependency even for maintainers
(in form of immutable branch / tag).
The easier way to provide Depends-on (when it's one patch), though
kbuild bot doesn't support it. Yet?

>  It is testing -next right?

It testing (1) and (2). (it was unable to apply against next by some
reason, but the build error is against latest vanilla failed. And this
is completely correct. Just follow the process (see above).

-- 
With Best Regards,
Andy Shevchenko