Hi,
Compilation of lsm_cgroup.c will fail if the vmlinux.h comes from a kernel that does _not_ have CONFIG_PACKET=y. The reason is that the definition of struct sockaddr_ll is not present in vmlinux.h and the compiler will complain that is has an incomplete type.
CLNG-BPF [test_maps] lsm_cgroup.bpf.o progs/lsm_cgroup.c:105:21: error: variable has incomplete type 'struct sockaddr_ll' 105 | struct sockaddr_ll sa = {}; | ^ progs/lsm_cgroup.c:105:9: note: forward declaration of 'struct sockaddr_ll' 105 | struct sockaddr_ll sa = {}; | ^ 1 error generated.
While including linux/if_packet.h somehow made the compilation works for me, IIUC this isn't a proper solution because vmlinux.h and kernel headers should not be used at the same time (and would lead to redefinition error when the kernel is built with CONFIG_PACKET=y, e.g. on BPF CI).
What would be the suggested way to work around this?
Thanks, Shung-Hsi
--- tools/testing/selftests/bpf/progs/lsm_cgroup.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/tools/testing/selftests/bpf/progs/lsm_cgroup.c b/tools/testing/selftests/bpf/progs/lsm_cgroup.c index 02c11d16b692..5394ec7ae1d8 100644 --- a/tools/testing/selftests/bpf/progs/lsm_cgroup.c +++ b/tools/testing/selftests/bpf/progs/lsm_cgroup.c @@ -2,6 +2,7 @@
#include "vmlinux.h" #include "bpf_tracing_net.h" +#include <linux/if_packet.h> #include <bpf/bpf_helpers.h> #include <bpf/bpf_tracing.h>
On Thu, 2024-01-18 at 19:58 +0800, Shung-Hsi Yu wrote:
Hi,
Compilation of lsm_cgroup.c will fail if the vmlinux.h comes from a kernel that does _not_ have CONFIG_PACKET=y. The reason is that the definition of struct sockaddr_ll is not present in vmlinux.h and the compiler will complain that is has an incomplete type.
CLNG-BPF [test_maps] lsm_cgroup.bpf.oprogs/lsm_cgroup.c:105:21: error: variable has incomplete type 'struct sockaddr_ll' 105 | struct sockaddr_ll sa = {}; | ^ progs/lsm_cgroup.c:105:9: note: forward declaration of 'struct sockaddr_ll' 105 | struct sockaddr_ll sa = {}; | ^ 1 error generated.
While including linux/if_packet.h somehow made the compilation works for me, IIUC this isn't a proper solution because vmlinux.h and kernel headers should not be used at the same time (and would lead to redefinition error when the kernel is built with CONFIG_PACKET=y, e.g. on BPF CI).
What would be the suggested way to work around this?
Thanks, Shung-Hsi
Hi Shung-Hsi,
One option is to use CO-RE, e.g. as at the bottom of this email (not sure if people would agree with me). But that would not produce usable test anyways, as load would fail with unresolved CO-RE relocation.
But what is your final goal? As far as I understand, selftests are supposed to be built and run using specific configuration, here is how config for x86 CI is prepared:
./scripts/kconfig/merge_config.sh \ ./tools/testing/selftests/bpf/config \ ./tools/testing/selftests/bpf/config.vm \ ./tools/testing/selftests/bpf/config.x86_64
(root is kernel source). I'm not sure if other configurations are supposed to be supported.
Thanks, Eduard
---
diff --git a/tools/testing/selftests/bpf/progs/lsm_cgroup.c b/tools/testing/selftests/bpf/progs/lsm_cgroup.c index 02c11d16b692..8381e5a202c8 100644 --- a/tools/testing/selftests/bpf/progs/lsm_cgroup.c +++ b/tools/testing/selftests/bpf/progs/lsm_cgroup.c @@ -2,6 +2,7 @@
#include "vmlinux.h" #include "bpf_tracing_net.h" +#include <bpf/bpf_core_read.h> #include <bpf/bpf_helpers.h> #include <bpf/bpf_tracing.h>
@@ -98,11 +99,15 @@ int BPF_PROG(socket_post_create2, struct socket *sock, int family, return real_create(sock, family, protocol); }
+struct sockaddr_ll___local { + __be16 sll_protocol; +} __attribute__((preserve_access_index)); + static __always_inline int real_bind(struct socket *sock, struct sockaddr *address, int addrlen) { - struct sockaddr_ll sa = {}; + __u16 sll_protocol = 0;
if (sock->sk->__sk_common.skc_family != AF_PACKET) return 1; @@ -110,8 +115,10 @@ static __always_inline int real_bind(struct socket *sock, if (sock->sk->sk_kern_sock) return 1;
- bpf_probe_read_kernel(&sa, sizeof(sa), address); - if (sa.sll_protocol) + bpf_probe_read_kernel( + &sll_protocol, sizeof(sll_protocol), + (__u8*)address + bpf_core_field_offset(struct sockaddr_ll___local, sll_protocol)); + if (sll_protocol) return 0; /* EPERM */
/* Can access cgroup local storage. */
On Thu, 2024-01-18 at 17:58 +0200, Eduard Zingerman wrote: [...]
here is how config for x86 CI is prepared:
./scripts/kconfig/merge_config.sh \ ./tools/testing/selftests/bpf/config \ ./tools/testing/selftests/bpf/config.vm \ ./tools/testing/selftests/bpf/config.x86_64
(For whatever reason CONFIG_PACKET is defined in .../config.x86_64, maybe that should be moved to .../config?)
On 1/18/24 8:05 AM, Eduard Zingerman wrote:
On Thu, 2024-01-18 at 17:58 +0200, Eduard Zingerman wrote: [...]
here is how config for x86 CI is prepared:
./scripts/kconfig/merge_config.sh \ ./tools/testing/selftests/bpf/config \ ./tools/testing/selftests/bpf/config.vm \ ./tools/testing/selftests/bpf/config.x86_64
(For whatever reason CONFIG_PACKET is defined in .../config.x86_64, maybe that should be moved to .../config?)
Sounds a good idea to me.
On Thu, Jan 18, 2024 at 05:58:20PM +0200, Eduard Zingerman wrote:
On Thu, 2024-01-18 at 19:58 +0800, Shung-Hsi Yu wrote:
Compilation of lsm_cgroup.c will fail if the vmlinux.h comes from a kernel that does _not_ have CONFIG_PACKET=y. The reason is that the definition of struct sockaddr_ll is not present in vmlinux.h and the compiler will complain that is has an incomplete type.
CLNG-BPF [test_maps] lsm_cgroup.bpf.oprogs/lsm_cgroup.c:105:21: error: variable has incomplete type 'struct sockaddr_ll' 105 | struct sockaddr_ll sa = {}; | ^ progs/lsm_cgroup.c:105:9: note: forward declaration of 'struct sockaddr_ll' 105 | struct sockaddr_ll sa = {}; | ^ 1 error generated.
[...]
Hi Shung-Hsi,
One option is to use CO-RE, e.g. as at the bottom of this email (not sure if people would agree with me). But that would not produce usable test anyways, as load would fail with unresolved CO-RE relocation.
But what is your final goal?
Final goal would be have BPF selftests compiled and test against our own kernel, without having to come up with a specific kernel flavor that is used to build and run the selftest. For v5.14 and v5.19-based kernel it works: compilation is successful and I was able to run the verifier tests. (Did not try running the other tests though)
As far as I understand, selftests are supposed to be built and run using specific configuration, here is how config for x86 CI is prepared:
./scripts/kconfig/merge_config.sh \ ./tools/testing/selftests/bpf/config \ ./tools/testing/selftests/bpf/config.vm \ ./tools/testing/selftests/bpf/config.x86_64
(root is kernel source). I'm not sure if other configurations are supposed to be supported.
Would it make sense to have makefile target that builds/runs a smaller subset of general, config-agnostic selftests that tests the core feature (e.g. verifier + instruction set)?
[...]
On Fri, 2024-01-19 at 16:04 +0800, Shung-Hsi Yu wrote:
[...]
Final goal would be have BPF selftests compiled and test against our own kernel, without having to come up with a specific kernel flavor that is used to build and run the selftest. For v5.14 and v5.19-based kernel it works: compilation is successful and I was able to run the verifier tests. (Did not try running the other tests though)
You mean ./test_verifier binary, right? A lot of tests had been moved from ./test_verifier to ./test_progs since.
As far as I understand, selftests are supposed to be built and run using specific configuration, here is how config for x86 CI is prepared:
./scripts/kconfig/merge_config.sh \ ./tools/testing/selftests/bpf/config \ ./tools/testing/selftests/bpf/config.vm \ ./tools/testing/selftests/bpf/config.x86_64
(root is kernel source). I'm not sure if other configurations are supposed to be supported.
Would it make sense to have makefile target that builds/runs a smaller subset of general, config-agnostic selftests that tests the core feature (e.g. verifier + instruction set)?
In ideal world I'd say that ./test_progs should include/exclude tests conditioned on current configuration, but I don't know how much work would it be to adapt build system for this.
On Fri, Jan 19, 2024 at 4:23 AM Eduard Zingerman eddyz87@gmail.com wrote:
On Fri, 2024-01-19 at 16:04 +0800, Shung-Hsi Yu wrote:
[...]
Final goal would be have BPF selftests compiled and test against our own kernel, without having to come up with a specific kernel flavor that is used to build and run the selftest. For v5.14 and v5.19-based kernel it works: compilation is successful and I was able to run the verifier tests. (Did not try running the other tests though)
You mean ./test_verifier binary, right? A lot of tests had been moved from ./test_verifier to ./test_progs since.
As far as I understand, selftests are supposed to be built and run using specific configuration, here is how config for x86 CI is prepared:
./scripts/kconfig/merge_config.sh \ ./tools/testing/selftests/bpf/config \ ./tools/testing/selftests/bpf/config.vm \ ./tools/testing/selftests/bpf/config.x86_64
(root is kernel source). I'm not sure if other configurations are supposed to be supported.
Would it make sense to have makefile target that builds/runs a smaller subset of general, config-agnostic selftests that tests the core feature (e.g. verifier + instruction set)?
In ideal world I'd say that ./test_progs should include/exclude tests conditioned on current configuration, but I don't know how much work would it be to adapt build system for this.
I would also suggest skipping building the specific bpf test code when a specific CONFIG is removed, sometimes I only want to test some bpf selftests code I am interested in :)
On Fri, Jan 19, 2024 at 7:00 AM Vincent Li vincent.mc.li@gmail.com wrote:
On Fri, Jan 19, 2024 at 4:23 AM Eduard Zingerman eddyz87@gmail.com wrote:
On Fri, 2024-01-19 at 16:04 +0800, Shung-Hsi Yu wrote:
[...]
Final goal would be have BPF selftests compiled and test against our own kernel, without having to come up with a specific kernel flavor that is used to build and run the selftest. For v5.14 and v5.19-based kernel it works: compilation is successful and I was able to run the verifier tests. (Did not try running the other tests though)
You mean ./test_verifier binary, right? A lot of tests had been moved from ./test_verifier to ./test_progs since.
As far as I understand, selftests are supposed to be built and run using specific configuration, here is how config for x86 CI is prepared:
./scripts/kconfig/merge_config.sh \ ./tools/testing/selftests/bpf/config \ ./tools/testing/selftests/bpf/config.vm \ ./tools/testing/selftests/bpf/config.x86_64
(root is kernel source). I'm not sure if other configurations are supposed to be supported.
Would it make sense to have makefile target that builds/runs a smaller subset of general, config-agnostic selftests that tests the core feature (e.g. verifier + instruction set)?
In ideal world I'd say that ./test_progs should include/exclude tests conditioned on current configuration, but I don't know how much work would it be to adapt build system for this.
I would also suggest skipping building the specific bpf test code when a specific CONFIG is removed, sometimes I only want to test some bpf selftests code I am interested in :)
I don't think we should be complicating bpf selftests to test configurations with reduced kconfig. bpf/config.* is what we target in bpf CI and we expect developers do the same amount of testing before they send patches.
On Fri, Jan 19, 2024 at 2:26 PM Alexei Starovoitov alexei.starovoitov@gmail.com wrote:
On Fri, Jan 19, 2024 at 7:00 AM Vincent Li vincent.mc.li@gmail.com wrote:
On Fri, Jan 19, 2024 at 4:23 AM Eduard Zingerman eddyz87@gmail.com wrote:
On Fri, 2024-01-19 at 16:04 +0800, Shung-Hsi Yu wrote:
[...]
Final goal would be have BPF selftests compiled and test against our own kernel, without having to come up with a specific kernel flavor that is used to build and run the selftest. For v5.14 and v5.19-based kernel it works: compilation is successful and I was able to run the verifier tests. (Did not try running the other tests though)
You mean ./test_verifier binary, right? A lot of tests had been moved from ./test_verifier to ./test_progs since.
As far as I understand, selftests are supposed to be built and run using specific configuration, here is how config for x86 CI is prepared:
./scripts/kconfig/merge_config.sh \ ./tools/testing/selftests/bpf/config \ ./tools/testing/selftests/bpf/config.vm \ ./tools/testing/selftests/bpf/config.x86_64
(root is kernel source). I'm not sure if other configurations are supposed to be supported.
Would it make sense to have makefile target that builds/runs a smaller subset of general, config-agnostic selftests that tests the core feature (e.g. verifier + instruction set)?
In ideal world I'd say that ./test_progs should include/exclude tests conditioned on current configuration, but I don't know how much work would it be to adapt build system for this.
I would also suggest skipping building the specific bpf test code when a specific CONFIG is removed, sometimes I only want to test some bpf selftests code I am interested in :)
I don't think we should be complicating bpf selftests to test configurations with reduced kconfig. bpf/config.* is what we target in bpf CI and we expect developers do the same amount of testing before they send patches.
Totally understand that from the kernel bpf developer perspective. I am a bpf user learning how to write a bpf program from selftests, but I guess there is another way to learn, selftests is not for teaching bpf users, no need to complicate.
On Fri, Jan 19, 2024 at 3:13 PM Vincent Li vincent.mc.li@gmail.com wrote:
On Fri, Jan 19, 2024 at 2:26 PM Alexei Starovoitov alexei.starovoitov@gmail.com wrote:
On Fri, Jan 19, 2024 at 7:00 AM Vincent Li vincent.mc.li@gmail.com wrote:
On Fri, Jan 19, 2024 at 4:23 AM Eduard Zingerman eddyz87@gmail.com wrote:
On Fri, 2024-01-19 at 16:04 +0800, Shung-Hsi Yu wrote:
[...]
Final goal would be have BPF selftests compiled and test against our own kernel, without having to come up with a specific kernel flavor that is used to build and run the selftest. For v5.14 and v5.19-based kernel it works: compilation is successful and I was able to run the verifier tests. (Did not try running the other tests though)
You mean ./test_verifier binary, right? A lot of tests had been moved from ./test_verifier to ./test_progs since.
As far as I understand, selftests are supposed to be built and run using specific configuration, here is how config for x86 CI is prepared:
./scripts/kconfig/merge_config.sh \ ./tools/testing/selftests/bpf/config \ ./tools/testing/selftests/bpf/config.vm \ ./tools/testing/selftests/bpf/config.x86_64
(root is kernel source). I'm not sure if other configurations are supposed to be supported.
Would it make sense to have makefile target that builds/runs a smaller subset of general, config-agnostic selftests that tests the core feature (e.g. verifier + instruction set)?
In ideal world I'd say that ./test_progs should include/exclude tests conditioned on current configuration, but I don't know how much work would it be to adapt build system for this.
I would also suggest skipping building the specific bpf test code when a specific CONFIG is removed, sometimes I only want to test some bpf selftests code I am interested in :)
I don't think we should be complicating bpf selftests to test configurations with reduced kconfig. bpf/config.* is what we target in bpf CI and we expect developers do the same amount of testing before they send patches.
Totally understand that from the kernel bpf developer perspective. I am a bpf user learning how to write a bpf program from selftests, but I guess there is another way to learn, selftests is not for teaching bpf users, no need to complicate.
Try libbpf-bootstrap ([0]) as a simple setup to play with new BPF features. minimal or bootstrap examples are usually good starting points.
On Fri, Jan 19, 2024 at 3:35 PM Andrii Nakryiko andrii.nakryiko@gmail.com wrote:
On Fri, Jan 19, 2024 at 3:13 PM Vincent Li vincent.mc.li@gmail.com wrote:
On Fri, Jan 19, 2024 at 2:26 PM Alexei Starovoitov alexei.starovoitov@gmail.com wrote:
On Fri, Jan 19, 2024 at 7:00 AM Vincent Li vincent.mc.li@gmail.com wrote:
On Fri, Jan 19, 2024 at 4:23 AM Eduard Zingerman eddyz87@gmail.com wrote:
On Fri, 2024-01-19 at 16:04 +0800, Shung-Hsi Yu wrote:
[...]
Final goal would be have BPF selftests compiled and test against our own kernel, without having to come up with a specific kernel flavor that is used to build and run the selftest. For v5.14 and v5.19-based kernel it works: compilation is successful and I was able to run the verifier tests. (Did not try running the other tests though)
You mean ./test_verifier binary, right? A lot of tests had been moved from ./test_verifier to ./test_progs since.
> As far as I understand, selftests are supposed to be built and run > using specific configuration, here is how config for x86 CI is prepared: > > ./scripts/kconfig/merge_config.sh \ > ./tools/testing/selftests/bpf/config \ > ./tools/testing/selftests/bpf/config.vm \ > ./tools/testing/selftests/bpf/config.x86_64 > > (root is kernel source). > I'm not sure if other configurations are supposed to be supported.
Would it make sense to have makefile target that builds/runs a smaller subset of general, config-agnostic selftests that tests the core feature (e.g. verifier + instruction set)?
In ideal world I'd say that ./test_progs should include/exclude tests conditioned on current configuration, but I don't know how much work would it be to adapt build system for this.
I would also suggest skipping building the specific bpf test code when a specific CONFIG is removed, sometimes I only want to test some bpf selftests code I am interested in :)
I don't think we should be complicating bpf selftests to test configurations with reduced kconfig. bpf/config.* is what we target in bpf CI and we expect developers do the same amount of testing before they send patches.
Totally understand that from the kernel bpf developer perspective. I am a bpf user learning how to write a bpf program from selftests, but I guess there is another way to learn, selftests is not for teaching bpf users, no need to complicate.
Try libbpf-bootstrap ([0]) as a simple setup to play with new BPF features. minimal or bootstrap examples are usually good starting points.
Thanks! I am aware of libbpf-bootstrap, I am on an old centos 8 distro which often miss linux headers that some selftests happens to require, especially the ones that are not using vmlinux.h, when a bpf kernel developer submit patches and selftests that I am interested in, I want to run that selftests and learn the new feature, and then probably port the new useful selftests code to a real use case bpf program. I often run into other selftests compiling errors when I want to selftest the new feature I am interested in. Anyway, it is my build environment problem, not selftests.
linux-kselftest-mirror@lists.linaro.org
-
Alexei Starovoitov -
Andrii Nakryiko -
Eduard Zingerman -
Shung-Hsi Yu -
Vincent Li -
Yonghong Song