2018-11-22 07:54:01

by Liam R. Howlett

Subject: Out of tree module build errors since v4.20-rc1

My out of tree driver build is now reporting issues with the jump table:

./include/linux/jump_label.h: In function ‘jump_entry_code’:
./include/linux/jump_label.h:153:14: error: dereferencing pointer to incomplete type ‘const struct jump_entry’
return entry->code;
^~
./include/linux/jump_label.h: In function ‘jump_entry_set_init’:
./include/linux/jump_label.h:180:7: error: dereferencing pointer to incomplete type ‘struct jump_entry’
entry->key |= 2;
^~
./include/linux/jump_label.h: At top level:
./include/linux/jump_label.h:212:26: error: array type has incomplete element type ‘struct jump_entry’
extern struct jump_entry __start___jump_table[];
^~~~~~~~~~~~~~~~~~~~
./include/linux/jump_label.h:213:26: error: array type has incomplete element type ‘struct jump_entry’
extern struct jump_entry __stop___jump_table[];
^~~~~~~~~~~~~~~~~~~


This happens in v4.20-rc3 as well, so I bisected between v4.19 to
v4.20-rc1 which resulted in the following commit:

b34006c4258c9c86597b6b7123d6a9a3513d6cd7 is the first bad commit
commit b34006c4258c9c86597b6b7123d6a9a3513d6cd7
Author: Ard Biesheuvel <[email protected]>
Date: Tue Sep 18 23:51:41 2018 -0700

x86/jump_table: Use relative references




Initially I assumed this was my own fault, but my module does not have
these issues when using v4.19. Is there anything I should try/change in
my module makefile, includes, etc to support this relative reference
code?



Thank you,
Liam

2018-11-22 07:54:42

by Nadav Amit

Subject: Re: Out of tree module build errors since v4.20-rc1

> On Nov 21, 2018, at 12:56 PM, Liam R. Howlett <[email protected]> wrote:
>
>
> My out of tree driver build is now reporting issues with the jump table:
>
> ./include/linux/jump_label.h: In function ‘jump_entry_code’:
> ./include/linux/jump_label.h:153:14: error: dereferencing pointer to incomplete type ‘const struct jump_entry’
> return entry->code;
> ^~
> ./include/linux/jump_label.h: In function ‘jump_entry_set_init’:
> ./include/linux/jump_label.h:180:7: error: dereferencing pointer to incomplete type ‘struct jump_entry’
> entry->key |= 2;
> ^~
> ./include/linux/jump_label.h: At top level:
> ./include/linux/jump_label.h:212:26: error: array type has incomplete element type ‘struct jump_entry’
> extern struct jump_entry __start___jump_table[];
> ^~~~~~~~~~~~~~~~~~~~
> ./include/linux/jump_label.h:213:26: error: array type has incomplete element type ‘struct jump_entry’
> extern struct jump_entry __stop___jump_table[];
> ^~~~~~~~~~~~~~~~~~~
>
>
> This happens in v4.20-rc3 as well, so I bisected between v4.19 to
> v4.20-rc1 which resulted in the following commit:
>
> b34006c4258c9c86597b6b7123d6a9a3513d6cd7 is the first bad commit
> commit b34006c4258c9c86597b6b7123d6a9a3513d6cd7
> Author: Ard Biesheuvel <[email protected]>
> Date: Tue Sep 18 23:51:41 2018 -0700
>
> x86/jump_table: Use relative references
>
>
>
>
> Initially I assumed this was my own fault, but my module does not have
> these issues when using v4.19. Is there anything I should try/change in
> my module makefile, includes, etc to support this relative reference
> code?

Do you see HAVE_ARCH_JUMP_LABEL_RELATIVE set in your kernel config?

2018-11-22 08:16:19

by Liam R. Howlett

Subject: Re: Out of tree module build errors since v4.20-rc1

* Nadav Amit <[email protected]> [181121 16:12]:
> > On Nov 21, 2018, at 12:56 PM, Liam R. Howlett <[email protected]> wrote:
> >
> >
> > My out of tree driver build is now reporting issues with the jump table:
> >
> > ./include/linux/jump_label.h: In function ‘jump_entry_code’:
> > ./include/linux/jump_label.h:153:14: error: dereferencing pointer to incomplete type ‘const struct jump_entry’
> > return entry->code;
> > ^~
> > ./include/linux/jump_label.h: In function ‘jump_entry_set_init’:
> > ./include/linux/jump_label.h:180:7: error: dereferencing pointer to incomplete type ‘struct jump_entry’
> > entry->key |= 2;
> > ^~
> > ./include/linux/jump_label.h: At top level:
> > ./include/linux/jump_label.h:212:26: error: array type has incomplete element type ‘struct jump_entry’
> > extern struct jump_entry __start___jump_table[];
> > ^~~~~~~~~~~~~~~~~~~~
> > ./include/linux/jump_label.h:213:26: error: array type has incomplete element type ‘struct jump_entry’
> > extern struct jump_entry __stop___jump_table[];
> > ^~~~~~~~~~~~~~~~~~~
> >
> >
> > This happens in v4.20-rc3 as well, so I bisected between v4.19 to
> > v4.20-rc1 which resulted in the following commit:
> >
> > b34006c4258c9c86597b6b7123d6a9a3513d6cd7 is the first bad commit
> > commit b34006c4258c9c86597b6b7123d6a9a3513d6cd7
> > Author: Ard Biesheuvel <[email protected]>
> > Date: Tue Sep 18 23:51:41 2018 -0700
> >
> > x86/jump_table: Use relative references
> >
> >
> >
> >
> > Initially I assumed this was my own fault, but my module does not have
> > these issues when using v4.19. Is there anything I should try/change in
> > my module makefile, includes, etc to support this relative reference
> > code?
>
> Do you see HAVE_ARCH_JUMP_LABEL_RELATIVE set in your kernel config?
>

Yes:
$ grep HAVE_ARCH_JUMP_LABEL_RELATIVE .config
CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE=y


I should have mentioned I ran 'make defoldconfig' between each bisect.

2018-11-22 08:47:27

by Ard Biesheuvel

Subject: Re: Out of tree module build errors since v4.20-rc1

On Wed, 21 Nov 2018 at 22:15, Liam R. Howlett <[email protected]> wrote:
>
> * Nadav Amit <[email protected]> [181121 16:12]:
> > > On Nov 21, 2018, at 12:56 PM, Liam R. Howlett <[email protected]> wrote:
> > >
> > >
> > > My out of tree driver build is now reporting issues with the jump table:
> > >
> > > ./include/linux/jump_label.h: In function ‘jump_entry_code’:
> > > ./include/linux/jump_label.h:153:14: error: dereferencing pointer to incomplete type ‘const struct jump_entry’
> > > return entry->code;
> > > ^~
> > > ./include/linux/jump_label.h: In function ‘jump_entry_set_init’:
> > > ./include/linux/jump_label.h:180:7: error: dereferencing pointer to incomplete type ‘struct jump_entry’
> > > entry->key |= 2;
> > > ^~
> > > ./include/linux/jump_label.h: At top level:
> > > ./include/linux/jump_label.h:212:26: error: array type has incomplete element type ‘struct jump_entry’
> > > extern struct jump_entry __start___jump_table[];
> > > ^~~~~~~~~~~~~~~~~~~~
> > > ./include/linux/jump_label.h:213:26: error: array type has incomplete element type ‘struct jump_entry’
> > > extern struct jump_entry __stop___jump_table[];
> > > ^~~~~~~~~~~~~~~~~~~
> > >
> > >
> > > This happens in v4.20-rc3 as well, so I bisected between v4.19 to
> > > v4.20-rc1 which resulted in the following commit:
> > >
> > > b34006c4258c9c86597b6b7123d6a9a3513d6cd7 is the first bad commit
> > > commit b34006c4258c9c86597b6b7123d6a9a3513d6cd7
> > > Author: Ard Biesheuvel <[email protected]>
> > > Date: Tue Sep 18 23:51:41 2018 -0700
> > >
> > > x86/jump_table: Use relative references
> > >
> > >
> > >
> > >
> > > Initially I assumed this was my own fault, but my module does not have
> > > these issues when using v4.19. Is there anything I should try/change in
> > > my module makefile, includes, etc to support this relative reference
> > > code?
> >
> > Do you see HAVE_ARCH_JUMP_LABEL_RELATIVE set in your kernel config?
> >
>
> Yes:
> $ grep HAVE_ARCH_JUMP_LABEL_RELATIVE .config
> CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE=y
>
>
> I should have mentioned I ran 'make defoldconfig' between each bisect.

That is puzzling. linux/jump_label.h defines a type struct
jump_label_entry if CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE is #define'd,
and so the error suggests that it is not.

Can you share the command line (with V=1) and the preprocessed result?
(Re-execute the failing GCC command but replace -c with -E)