linux-next: build failure after merge of the akpm-current tree

linux-next: build failure after merge of the akpm-current tree

[Stephen Rothwell]

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Hi Andrew,

After merging the akpm tree, today's linux-next build (powerpc
allyesconfig) failed like this:

In file included from include/linux/kernel.h:10:0,
                 from include/linux/list.h:9,
                 from include/linux/preempt.h:11,
                 from include/linux/spinlock.h:51,
                 from include/linux/seqlock.h:36,
                 from include/linux/time.h:6,
                 from fs/proc/inode.c:9:
fs/proc/inode.c: In function 'proc_init_kmemcache':
include/linux/compiler.h:339:38: error: call to '__compiletime_assert_110' declared with attribute error: BUILD_BUG_ON failed: sizeof(struct proc_dir_entry) >= SIZEOF_PDE
  _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
                                      ^
include/linux/compiler.h:319:4: note: in definition of macro '__compiletime_assert'
    prefix ## suffix();    \
    ^~~~~~
include/linux/compiler.h:339:2: note: in expansion of macro '_compiletime_assert'
  _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
  ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:45:37: note: in expansion of macro 'compiletime_assert'
 #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
                                     ^~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:69:2: note: in expansion of macro 'BUILD_BUG_ON_MSG'
  BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
  ^~~~~~~~~~~~~~~~
fs/proc/inode.c:110:2: note: in expansion of macro 'BUILD_BUG_ON'
  BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
  ^~~~~~~~~~~~

Caused by commit

  527ae8759f10 ("proc: fixup PDE allocation bloat")

I have reverted that commit for today.

-- 
Cheers,
Stephen Rothwell

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Re: linux-next: build failure after merge of the akpm-current tree

[Alexey Dobriyan]

On Fri, Jun 29, 2018 at 05:49:46PM +1000, Stephen Rothwell wrote:
> fs/proc/inode.c:110:2: note: in expansion of macro 'BUILD_BUG_ON'
>   BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
>   ^~~~~~~~~~~~
> 
> Caused by commit
> 
>   527ae8759f10 ("proc: fixup PDE allocation bloat")
> 
> I have reverted that commit for today.

Can't reproduce it with commit 7aa4b0a46be8badd053c958481f0e89e634ae4df
(the one before revert) both on 32-bit and 64-bit.

Can you post fs/proc/inode.i ?

Re: linux-next: build failure after merge of the akpm-current tree

[Stephen Rothwell]

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Hi Alexey,

On Sat, 30 Jun 2018 00:25:22 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote:
>
> On Fri, Jun 29, 2018 at 05:49:46PM +1000, Stephen Rothwell wrote:
> > fs/proc/inode.c:110:2: note: in expansion of macro 'BUILD_BUG_ON'
> >   BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
> >   ^~~~~~~~~~~~
> > 
> > Caused by commit
> > 
> >   527ae8759f10 ("proc: fixup PDE allocation bloat")
> > 
> > I have reverted that commit for today.  
> 
> Can't reproduce it with commit 7aa4b0a46be8badd053c958481f0e89e634ae4df
> (the one before revert) both on 32-bit and 64-bit.
> 
> Can you post fs/proc/inode.i ?

Attached (xz compresesed).

This is built with gcc 7.3.1 (built from source) hosted on PowerPC LE
and targeted at PowerPC BE (a powerpc allyesconfig build).  I did not
have any trouble with any of my other PowerPC targeted builds.

-- 
Cheers,
Stephen Rothwell

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[PATCH -mm] proc: fix BUILD_BUG_ON breakage on powerpc64

[Alexey Dobriyan]

On Sat, Jun 30, 2018 at 01:18:22PM +1000, Stephen Rothwell wrote:
> Hi Alexey,
> 
> On Sat, 30 Jun 2018 00:25:22 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote:
> >
> > On Fri, Jun 29, 2018 at 05:49:46PM +1000, Stephen Rothwell wrote:
> > > fs/proc/inode.c:110:2: note: in expansion of macro 'BUILD_BUG_ON'
> > >   BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
> > >   ^~~~~~~~~~~~
> > > 
> > > Caused by commit
> > > 
> > >   527ae8759f10 ("proc: fixup PDE allocation bloat")
> > > 
> > > I have reverted that commit for today.  
> > 
> > Can't reproduce it with commit 7aa4b0a46be8badd053c958481f0e89e634ae4df
> > (the one before revert) both on 32-bit and 64-bit.
> > 
> > Can you post fs/proc/inode.i ?
> 
> Attached (xz compresesed).
> 
> This is built with gcc 7.3.1 (built from source) hosted on PowerPC LE
> and targeted at PowerPC BE (a powerpc allyesconfig build).  I did not
> have any trouble with any of my other PowerPC targeted builds.

I'm not sure what's going on. Taking preprocessed file and compiling it
with ppc64 cross compiler gives sizeof(struct proc_dir_entry) = 232.

Anyway here is obvious fixlet:

[PATCH -mm] proc: fix BUILD_BUG_ON breakage on powerpc64-allyesconfig

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---

 fs/proc/internal.h |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -65,12 +65,12 @@ struct proc_dir_entry {
 	char inline_name[];
 } __randomize_layout;
 
-#ifdef CONFIG_64BIT
-#define SIZEOF_PDE	(sizeof(spinlock_t) <= 4 ? 192 : 256)
-#else
-#define SIZEOF_PDE	(sizeof(spinlock_t) <= 4 ? 128 : 192)
-#endif
-
+#define SIZEOF_PDE	(				\
+	sizeof(struct proc_dir_entry) < 128 ? 128 :	\
+	sizeof(struct proc_dir_entry) < 192 ? 192 :	\
+	sizeof(struct proc_dir_entry) < 256 ? 256 :	\
+	sizeof(struct proc_dir_entry) < 512 ? 512 :	\
+	0)
 #define SIZEOF_PDE_INLINE_NAME (SIZEOF_PDE - sizeof(struct proc_dir_entry))
 
 extern struct kmem_cache *proc_dir_entry_cache;