[PATCH] selftests/bpf: Fix bpf selftest build error

[PATCH] selftests/bpf: Fix bpf selftest build error

[Saket Kumar Bhaskar]

On linux-next, build for bpf selftest displays an error due to
mismatch in the expected function signature of bpf_testmod_test_read
and bpf_testmod_test_write.

Commit 97d06802d10a ("sysfs: constify bin_attribute argument of bin_attribute::read/write()")
changed the required type for struct bin_attribute to const struct bin_attribute.

To resolve the error, update corresponding signature for the callback.

Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Closes: https://lore.kernel.org/all/e915da49-2b9a-4c4c-a34f-877f378129f6@linux.ibm.com/
Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
---
 tools/testing/selftests/bpf/test_kmods/bpf_testmod.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
index 2e54b95ad898..194c442580ee 100644
--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
@@ -385,7 +385,7 @@ int bpf_testmod_fentry_ok;
 
 noinline ssize_t
 bpf_testmod_test_read(struct file *file, struct kobject *kobj,
-		      struct bin_attribute *bin_attr,
+		      const struct bin_attribute *bin_attr,
 		      char *buf, loff_t off, size_t len)
 {
 	struct bpf_testmod_test_read_ctx ctx = {
@@ -465,7 +465,7 @@ ALLOW_ERROR_INJECTION(bpf_testmod_test_read, ERRNO);
 
 noinline ssize_t
 bpf_testmod_test_write(struct file *file, struct kobject *kobj,
-		      struct bin_attribute *bin_attr,
+		      const struct bin_attribute *bin_attr,
 		      char *buf, loff_t off, size_t len)
 {
 	struct bpf_testmod_test_write_ctx ctx = {
-- 
2.43.5

Re: [PATCH] selftests/bpf: Fix bpf selftest build error

[Alexei Starovoitov]

On Fri, May 9, 2025 at 5:24 AM Saket Kumar Bhaskar <skb99@linux.ibm.com> wrote:
>
> On linux-next, build for bpf selftest displays an error due to
> mismatch in the expected function signature of bpf_testmod_test_read
> and bpf_testmod_test_write.
>
> Commit 97d06802d10a ("sysfs: constify bin_attribute argument of bin_attribute::read/write()")
> changed the required type for struct bin_attribute to const struct bin_attribute.
>
> To resolve the error, update corresponding signature for the callback.
>
> Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
> Closes: https://lore.kernel.org/all/e915da49-2b9a-4c4c-a34f-877f378129f6@linux.ibm.com/
> Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
> ---
>  tools/testing/selftests/bpf/test_kmods/bpf_testmod.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
> index 2e54b95ad898..194c442580ee 100644
> --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
> +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
> @@ -385,7 +385,7 @@ int bpf_testmod_fentry_ok;
>
>  noinline ssize_t
>  bpf_testmod_test_read(struct file *file, struct kobject *kobj,
> -                     struct bin_attribute *bin_attr,
> +                     const struct bin_attribute *bin_attr,
>                       char *buf, loff_t off, size_t len)

You didn't even compile it :(

Instead of fixing the build, it breaks the build.

pw-bot: cr

Re: [PATCH] selftests/bpf: Fix bpf selftest build error

[Stephen Rothwell]

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Hi Alexei,

On Fri, 9 May 2025 10:04:18 -0700 Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
>
> On Fri, May 9, 2025 at 5:24 AM Saket Kumar Bhaskar <skb99@linux.ibm.com> wrote:
> >
> > On linux-next, build for bpf selftest displays an error due to
> > mismatch in the expected function signature of bpf_testmod_test_read
> > and bpf_testmod_test_write.
> >
> > Commit 97d06802d10a ("sysfs: constify bin_attribute argument of bin_attribute::read/write()")
> > changed the required type for struct bin_attribute to const struct bin_attribute.
> >
> > To resolve the error, update corresponding signature for the callback.
> >
> > Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
> > Closes: https://lore.kernel.org/all/e915da49-2b9a-4c4c-a34f-877f378129f6@linux.ibm.com/
> > Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
> > ---
> >  tools/testing/selftests/bpf/test_kmods/bpf_testmod.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
> > index 2e54b95ad898..194c442580ee 100644
> > --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
> > +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
> > @@ -385,7 +385,7 @@ int bpf_testmod_fentry_ok;
> >
> >  noinline ssize_t
> >  bpf_testmod_test_read(struct file *file, struct kobject *kobj,
> > -                     struct bin_attribute *bin_attr,
> > +                     const struct bin_attribute *bin_attr,
> >                       char *buf, loff_t off, size_t len)  
> 
> You didn't even compile it :(
> 
> Instead of fixing the build, it breaks the build.
> 
> pw-bot: cr

This patch is only needed in linux-next.  It should be applied to the
driver-core tree - since that includes commit 97d06802d10a.  It should
also have a Fixes tag referencing commit 97d06802d10a.
-- 
Cheers,
Stephen Rothwell

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Re: [PATCH] selftests/bpf: Fix bpf selftest build error

[Saket Kumar Bhaskar]

On Sat, May 10, 2025 at 11:04:55AM +1000, Stephen Rothwell wrote:
> Hi Alexei,
> 
> On Fri, 9 May 2025 10:04:18 -0700 Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
> >
> > On Fri, May 9, 2025 at 5:24 AM Saket Kumar Bhaskar <skb99@linux.ibm.com> wrote:
> > >
> > > On linux-next, build for bpf selftest displays an error due to
> > > mismatch in the expected function signature of bpf_testmod_test_read
> > > and bpf_testmod_test_write.
> > >
> > > Commit 97d06802d10a ("sysfs: constify bin_attribute argument of bin_attribute::read/write()")
> > > changed the required type for struct bin_attribute to const struct bin_attribute.
> > >
> > > To resolve the error, update corresponding signature for the callback.
> > >
> > > Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
> > > Closes: https://lore.kernel.org/all/e915da49-2b9a-4c4c-a34f-877f378129f6@linux.ibm.com/
> > > Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
> > > ---
> > >  tools/testing/selftests/bpf/test_kmods/bpf_testmod.c | 4 ++--
> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
> > > index 2e54b95ad898..194c442580ee 100644
> > > --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
> > > +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
> > > @@ -385,7 +385,7 @@ int bpf_testmod_fentry_ok;
> > >
> > >  noinline ssize_t
> > >  bpf_testmod_test_read(struct file *file, struct kobject *kobj,
> > > -                     struct bin_attribute *bin_attr,
> > > +                     const struct bin_attribute *bin_attr,
> > >                       char *buf, loff_t off, size_t len)  
> > 
> > You didn't even compile it :(
> > 
> > Instead of fixing the build, it breaks the build.
> > 
> > pw-bot: cr
> 
> This patch is only needed in linux-next.  It should be applied to the
> driver-core tree - since that includes commit 97d06802d10a.  It should
> also have a Fixes tag referencing commit 97d06802d10a.
> -- 
> Cheers,
> Stephen Rothwell
Hi Stephen,

Apologies for missing the Fixes tag. Would you like me to resend the patch with the 
Fixes tag included?

Thanks,
Saket

Re: [PATCH] selftests/bpf: Fix bpf selftest build error

[Stephen Rothwell]

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Hi Saket,

On Mon, 12 May 2025 10:55:59 +0530 Saket Kumar Bhaskar <skb99@linux.ibm.com> wrote:
> 
> Apologies for missing the Fixes tag. Would you like me to resend the patch with the 
> Fixes tag included?

Yes, please, but send it to Greg (keeping the ccs) so that he can apply
it to the driver-core tree.

-- 
Cheers,
Stephen Rothwell

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Re: [PATCH] selftests/bpf: Fix bpf selftest build error

[Venkat Rao Bagalkote]

On 09/05/25 5:53 pm, Saket Kumar Bhaskar wrote:
> On linux-next, build for bpf selftest displays an error due to
> mismatch in the expected function signature of bpf_testmod_test_read
> and bpf_testmod_test_write.
>
> Commit 97d06802d10a ("sysfs: constify bin_attribute argument of bin_attribute::read/write()")
> changed the required type for struct bin_attribute to const struct bin_attribute.
>
> To resolve the error, update corresponding signature for the callback.
>
> Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
> Closes: https://lore.kernel.org/all/e915da49-2b9a-4c4c-a34f-877f378129f6@linux.ibm.com/
> Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com>
> ---
>   tools/testing/selftests/bpf/test_kmods/bpf_testmod.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
> index 2e54b95ad898..194c442580ee 100644
> --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
> +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
> @@ -385,7 +385,7 @@ int bpf_testmod_fentry_ok;
>   
>   noinline ssize_t
>   bpf_testmod_test_read(struct file *file, struct kobject *kobj,
> -		      struct bin_attribute *bin_attr,
> +		      const struct bin_attribute *bin_attr,
>   		      char *buf, loff_t off, size_t len)
>   {
>   	struct bpf_testmod_test_read_ctx ctx = {
> @@ -465,7 +465,7 @@ ALLOW_ERROR_INJECTION(bpf_testmod_test_read, ERRNO);
>   
>   noinline ssize_t
>   bpf_testmod_test_write(struct file *file, struct kobject *kobj,
> -		      struct bin_attribute *bin_attr,
> +		      const struct bin_attribute *bin_attr,
>   		      char *buf, loff_t off, size_t len)
>   {
>   	struct bpf_testmod_test_write_ctx ctx = {


Tested this patch by applying on top of next-20250508 and if fixes the 
build issue. Hence,


Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>


commit f48887a98b78880b7711aca311fbbbcaad6c4e3b (tag: next-20250508, 
origin/master, origin/HEAD, bpf_arena)
Author: Stephen Rothwell <sfr@canb.auug.org.au>
Date:   Thu May 8 18:45:50 2025 +1000

     Add linux-next specific files for 20250508


After this patch:


   TEST-OBJ [test_progs-cpuv4] xdp_flowtable.test.o
   TEST-OBJ [test_progs-cpuv4] xdp_info.test.o
   TEST-OBJ [test_progs-cpuv4] xdp_link.test.o
   TEST-OBJ [test_progs-cpuv4] xdp_metadata.test.o
   TEST-OBJ [test_progs-cpuv4] xdp_noinline.test.o
   TEST-OBJ [test_progs-cpuv4] xdp_perf.test.o
   TEST-OBJ [test_progs-cpuv4] xdp_synproxy.test.o
   TEST-OBJ [test_progs-cpuv4] xdp_vlan.test.o
   TEST-OBJ [test_progs-cpuv4] xdpwall.test.o
   TEST-OBJ [test_progs-cpuv4] xfrm_info.test.o
   BINARY   bench
   BINARY   test_maps
   BINARY   test_progs
   BINARY   test_progs-no_alu32
   BINARY   test_progs-cpuv4



Before this patch:


   CLANG 
/root/linux-next/tools/testing/selftests/bpf/tools/build/bpftool/profiler.bpf.o
bpf_testmod.c:494:17: error: initialization of ‘ssize_t (*)(struct file 
*, struct kobject *, const struct bin_attribute *, char *, loff_t,  
size_t)’ {aka ‘long int (*)(struct file *, struct kobject *, const 
struct bin_attribute *, char *, long long int,  long unsigned int)’} 
from incompatible pointer type ‘ssize_t (*)(struct file *, struct 
kobject *, struct bin_attribute *, char *, loff_t, size_t)’ {aka ‘long 
int (*)(struct file *, struct kobject *, struct bin_attribute *, char *, 
long long int,  long unsigned int)’} [-Wincompatible-pointer-types]
   494 |         .read = bpf_testmod_test_read,
       |                 ^~~~~~~~~~~~~~~~~~~~~
bpf_testmod.c:494:17: note: (near initialization for 
‘bin_attr_bpf_testmod_file.read’)
bpf_testmod.c:495:18: error: initialization of ‘ssize_t (*)(struct file 
*, struct kobject *, const struct bin_attribute *, char *, loff_t,  
size_t)’ {aka ‘long int (*)(struct file *, struct kobject *, const 
struct bin_attribute *, char *, long long int,  long unsigned int)’} 
from incompatible pointer type ‘ssize_t (*)(struct file *, struct 
kobject *, struct bin_attribute *, char *, loff_t, size_t)’ {aka ‘long 
int (*)(struct file *, struct kobject *, struct bin_attribute *, char *, 
long long int,  long unsigned int)’} [-Wincompatible-pointer-types]
   495 |         .write = bpf_testmod_test_write,
       |                  ^~~~~~~~~~~~~~~~~~~~~~
bpf_testmod.c:495:18: note: (near initialization for 
‘bin_attr_bpf_testmod_file.write’)
make[4]: *** [/root/linux-next/scripts/Makefile.build:203: 
bpf_testmod.o] Error 1
make[3]: *** [/root/linux-next/Makefile:2009: .] Error 2
make[2]: *** [Makefile:248: __sub-make] Error 2
make[1]: *** [Makefile:18: all] Error 2
make: *** [Makefile:282: test_kmods/bpf_testmod.ko] Error 2


Regards,

Venkat.