Re: [PATCH bpf-next v3 5/5] selftests/bpf: Add private stack tests

[Jiri Olsa <olsajiri@gmail.com>]

On Thu, Sep 26, 2024 at 04:45:31PM -0700, Yonghong Song wrote:
> Some private stack tests are added including:
>   - prog with stack size greater than BPF_PSTACK_MIN_SUBTREE_SIZE.
>   - prog with stack size less than BPF_PSTACK_MIN_SUBTREE_SIZE.
>   - prog with one subprog having MAX_BPF_STACK stack size and another
>     subprog having non-zero stack size.
>   - prog with callback function.
>   - prog with exception in main prog or subprog.
> 
> Signed-off-by: Yonghong Song <yonghong.song@linux.dev>

hi,
might be some fail on my side, but I had to include bpf_experimental.h to
compile this.. ci seems ok

  CLNG-BPF [test_progs-cpuv4] verifier_private_stack.bpf.o
progs/verifier_private_stack.c:174:2: error: call to undeclared function 'bpf_throw'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
  174 |         bpf_throw(0);

jirka

> ---
>  .../selftests/bpf/prog_tests/verifier.c       |   2 +
>  .../bpf/progs/verifier_private_stack.c        | 215 ++++++++++++++++++
>  2 files changed, 217 insertions(+)
>  create mode 100644 tools/testing/selftests/bpf/progs/verifier_private_stack.c
> 
> diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c
> index e26b5150fc43..635ff3509403 100644
> --- a/tools/testing/selftests/bpf/prog_tests/verifier.c
> +++ b/tools/testing/selftests/bpf/prog_tests/verifier.c
> @@ -59,6 +59,7 @@
>  #include "verifier_or_jmp32_k.skel.h"
>  #include "verifier_precision.skel.h"
>  #include "verifier_prevent_map_lookup.skel.h"
> +#include "verifier_private_stack.skel.h"
>  #include "verifier_raw_stack.skel.h"
>  #include "verifier_raw_tp_writable.skel.h"
>  #include "verifier_reg_equal.skel.h"
> @@ -185,6 +186,7 @@ void test_verifier_bpf_fastcall(void)         { RUN(verifier_bpf_fastcall); }
>  void test_verifier_or_jmp32_k(void)           { RUN(verifier_or_jmp32_k); }
>  void test_verifier_precision(void)            { RUN(verifier_precision); }
>  void test_verifier_prevent_map_lookup(void)   { RUN(verifier_prevent_map_lookup); }
> +void test_verifier_private_stack(void)        { RUN(verifier_private_stack); }
>  void test_verifier_raw_stack(void)            { RUN(verifier_raw_stack); }
>  void test_verifier_raw_tp_writable(void)      { RUN(verifier_raw_tp_writable); }
>  void test_verifier_reg_equal(void)            { RUN(verifier_reg_equal); }
> diff --git a/tools/testing/selftests/bpf/progs/verifier_private_stack.c b/tools/testing/selftests/bpf/progs/verifier_private_stack.c
> new file mode 100644
> index 000000000000..badd1fd1e3dd
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/verifier_private_stack.c
> @@ -0,0 +1,215 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <vmlinux.h>
> +#include <bpf/bpf_helpers.h>
> +#include "bpf_misc.h"
> +
> +/* From include/linux/filter.h */
> +#define MAX_BPF_STACK    512
> +
> +#if defined(__TARGET_ARCH_x86)
> +
> +SEC("kprobe")
> +__description("Private stack, single prog")
> +__success
> +__arch_x86_64
> +__jited("	movabsq	$0x{{.*}}, %r9")
> +__jited("	addq	%gs:0x{{.*}}, %r9")
> +__jited("	movl	$0x2a, %edi")
> +__jited("	movq	%rdi, -0x100(%r9)")
> +__naked void private_stack_single_prog(void)
> +{
> +	asm volatile (
> +	"r1 = 42;"
> +	"*(u64 *)(r10 - 256) = r1;"
> +	"r0 = 0;"
> +	"exit;"
> +	:
> +	:
> +	: __clobber_all);
> +}
> +
> +__used
> +__naked static void cumulative_stack_depth_subprog(void)
> +{
> +        asm volatile (
> +	"r1 = 41;"
> +        "*(u64 *)(r10 - 32) = r1;"
> +        "call %[bpf_get_smp_processor_id];"
> +        "exit;"
> +        :: __imm(bpf_get_smp_processor_id)
> +	: __clobber_all);
> +}
> +
> +SEC("kprobe")
> +__description("Private stack, subtree > MAX_BPF_STACK")
> +__success
> +__arch_x86_64
> +/* private stack fp for the main prog */
> +__jited("	movabsq	$0x{{.*}}, %r9")
> +__jited("	addq	%gs:0x{{.*}}, %r9")
> +__jited("	movl	$0x2a, %edi")
> +__jited("	movq	%rdi, -0x200(%r9)")
> +__jited("	pushq	%r9")
> +__jited("	callq	0x{{.*}}")
> +__jited("	popq	%r9")
> +__jited("	xorl	%eax, %eax")
> +__naked void private_stack_nested_1(void)
> +{
> +	asm volatile (
> +	"r1 = 42;"
> +	"*(u64 *)(r10 - %[max_bpf_stack]) = r1;"
> +	"call cumulative_stack_depth_subprog;"
> +	"r0 = 0;"
> +	"exit;"
> +	:
> +	: __imm_const(max_bpf_stack, MAX_BPF_STACK)
> +	: __clobber_all);
> +}
> +
> +SEC("kprobe")
> +__description("Private stack, subtree > MAX_BPF_STACK")
> +__success
> +__arch_x86_64
> +/* private stack fp for the subprog */
> +__jited("	addq	$0x20, %r9")
> +__naked void private_stack_nested_2(void)
> +{
> +	asm volatile (
> +	"r1 = 42;"
> +	"*(u64 *)(r10 - %[max_bpf_stack]) = r1;"
> +	"call cumulative_stack_depth_subprog;"
> +	"r0 = 0;"
> +	"exit;"
> +	:
> +	: __imm_const(max_bpf_stack, MAX_BPF_STACK)
> +	: __clobber_all);
> +}
> +
> +SEC("raw_tp")
> +__description("No private stack, nested")
> +__success
> +__arch_x86_64
> +__jited("	subq	$0x8, %rsp")
> +__naked void no_private_stack_nested(void)
> +{
> +	asm volatile (
> +	"r1 = 42;"
> +	"*(u64 *)(r10 - 8) = r1;"
> +	"call cumulative_stack_depth_subprog;"
> +	"r0 = 0;"
> +	"exit;"
> +	:
> +	:
> +	: __clobber_all);
> +}
> +
> +__naked __noinline __used
> +static unsigned long loop_callback()
> +{
> +	asm volatile (
> +	"call %[bpf_get_prandom_u32];"
> +	"r1 = 42;"
> +	"*(u64 *)(r10 - 512) = r1;"
> +	"call cumulative_stack_depth_subprog;"
> +	"r0 = 0;"
> +	"exit;"
> +	:
> +	: __imm(bpf_get_prandom_u32)
> +	: __clobber_common);
> +}
> +
> +SEC("raw_tp")
> +__description("Private stack, callback")
> +__success
> +__arch_x86_64
> +/* for func loop_callback */
> +__jited("func #1")
> +__jited("	endbr64")
> +__jited("	nopl	(%rax,%rax)")
> +__jited("	nopl	(%rax)")
> +__jited("	pushq	%rbp")
> +__jited("	movq	%rsp, %rbp")
> +__jited("	endbr64")
> +__jited("	movabsq	$0x{{.*}}, %r9")
> +__jited("	addq	%gs:0x{{.*}}, %r9")
> +__jited("	pushq	%r9")
> +__jited("	callq")
> +__jited("	popq	%r9")
> +__jited("	movl	$0x2a, %edi")
> +__jited("	movq	%rdi, -0x200(%r9)")
> +__jited("	pushq	%r9")
> +__jited("	callq")
> +__jited("	popq	%r9")
> +__naked void private_stack_callback(void)
> +{
> +	asm volatile (
> +	"r1 = 1;"
> +	"r2 = %[loop_callback];"
> +	"r3 = 0;"
> +	"r4 = 0;"
> +	"call %[bpf_loop];"
> +	"r0 = 0;"
> +	"exit;"
> +	:
> +	: __imm_ptr(loop_callback),
> +	  __imm(bpf_loop)
> +	: __clobber_common);
> +}
> +
> +SEC("fentry/bpf_fentry_test9")
> +__description("Private stack, exception in main prog")
> +__success __retval(0)
> +__arch_x86_64
> +__jited("	pushq	%r9")
> +__jited("	callq")
> +__jited("	popq	%r9")
> +int private_stack_exception_main_prog(void)
> +{
> +	asm volatile (
> +	"r1 = 42;"
> +	"*(u64 *)(r10 - 512) = r1;"
> +	::: __clobber_common);
> +
> +	bpf_throw(0);
> +	return 0;
> +}
> +
> +__used static int subprog_exception(void)
> +{
> +	bpf_throw(0);
> +	return 0;
> +}
> +
> +SEC("fentry/bpf_fentry_test9")
> +__description("Private stack, exception in subprog")
> +__success __retval(0)
> +__arch_x86_64
> +__jited("	movq	%rdi, -0x200(%r9)")
> +__jited("	pushq	%r9")
> +__jited("	callq")
> +__jited("	popq	%r9")
> +int private_stack_exception_sub_prog(void)
> +{
> +	asm volatile (
> +	"r1 = 42;"
> +	"*(u64 *)(r10 - 512) = r1;"
> +	"call subprog_exception;"
> +	::: __clobber_common);
> +
> +	return 0;
> +}
> +
> +#else
> +
> +SEC("kprobe")
> +__description("private stack is not supported, use a dummy test")
> +__success
> +int dummy_test(void)
> +{
> +        return 0;
> +}
> +
> +#endif
> +
> +char _license[] SEC("license") = "GPL";
> -- 
> 2.43.5
> 
>