[RESEND PATCH 0/2][SRU][DISCO][EOAN] seccomp: fix selftests compilation

[Kleber Souza]

On 2019-10-28 18:25, Christian Brauner wrote:
> On Mon, Oct 28, 2019 at 05:40:04PM +0100, Kleber Souza wrote:
>> On 22.10.19 11:36, Christian Brauner wrote:
>>> Hey everyone,
>>>
>>> BugLink: https://bugs.launchpad.net/bugs/1849281
>>>
>>> This contains two small fixes for the seccomp selftests so they can be
>>> compiled on older kernels.
>>> The first patch is upstream, the second one is in Kees tree targeted for
>>> inclusion in v5.5. The latter one needs to be backported because we
>>> backported the SECCOMP_USER_NOTIF_FLAG_CONTINUE feature
>>> (cf. https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1847744)
>>>
>>> Thanks!
>>> Christian
>>>
>>> Christian Brauner (1):
>>>   UBUNTU: SAUCE: seccomp: fix SECCOMP_USER_NOTIF_FLAG_CONTINUE test
>>>
>>> Tycho Andersen (1):
>>>   selftests/seccomp: fix build on older kernels
>>>
>>>  tools/testing/selftests/seccomp/seccomp_bpf.c | 13 +++++++++----
>>>  1 file changed, 9 insertions(+), 4 deletions(-)
>>>
>>
>> Hi Christian,
>>
>> When compiling your seccomp testcase I get the following error
>> when doing it in a disco VM (with or without these follow up
>> fixes):
>>
>> make[1]: Entering directory '/home/ubuntu/disco/linux/tools/testing/selftests/seccomp'
>> gcc -Wl,-no-as-needed -Wall  seccomp_bpf.c -lpthread -o seccomp_bpf
>> seccomp_bpf.c: In function ‘user_notification_continue’:
>> seccomp_bpf.c:3074:26: warning: overflow in conversion from ‘long int’ to ‘__s32’ {aka ‘int’} changes value from ‘116983961184613’ to ‘1936943461’ [-Woverflow]
>>  #define USER_NOTIF_MAGIC 116983961184613L
> 
> Ah yeah, I sent a fix for that upstream too. Yes, that's a problem
> that's been around since 5.0. The fix for it is in Kees tree as
> 223e660bc763 ("seccomp: avoid overflow in implicit constant conversion")
> https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/commit/?h=for-next/seccomp&id=223e660bc7638d126a0e4fbace4f33f2895788c4
> 
> Sorry, that would need to be backported as well. :(

Even after applying the 3 patches you mentioned:

 * selftests/seccomp: fix build on older kernels
 * UBUNTU: SAUCE: seccomp: fix SECCOMP_USER_NOTIF_FLAG_CONTINUE test
 * seccomp: avoid overflow in implicit constant conversion

I still get the error:

$ make -C tools/testing/selftests/
[...]
make[1]: Entering directory '/home/ubuntu/disco-git/tools/testing/selftests/seccomp'
gcc -Wl,-no-as-needed -Wall  seccomp_bpf.c -lpthread -o seccomp_bpf
/usr/bin/ld: /tmp/ccVoJj77.o: in function `user_notification_continue':
seccomp_bpf.c:(.text+0x2e1e4): undefined reference to `BIT'


It seems we also need your other patch:

 * seccomp: rework define for SECCOMP_USER_NOTIF_FLAG_CONTINUE
   https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/commit/?h=for-next/seccomp&id=23b2c96fad21886c53f5e1a4ffedd45ddd2e85ba

because compiling selftests from the source pkg will include
'/usr/include/linux/seccomp.h', which is installed by linux-libc-dev.


Thanks,
Kleber