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Yonghong SongAlexei Starovoitov
Yonghong Song
authored and
Alexei Starovoitov
committed
selftests/bpf: Add tracing prog private stack tests
Some private stack tests are added including: - main prog only with stack size greater than BPF_PSTACK_MIN_SIZE. - main prog only with stack size smaller than BPF_PSTACK_MIN_SIZE. - prog with one subprog having MAX_BPF_STACK stack size and another subprog having non-zero small stack size. - prog with callback function. - prog with exception in main prog or subprog. - prog with async callback without nesting - prog with async callback with possible nesting Signed-off-by: Yonghong Song <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
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‎tools/testing/selftests/bpf/prog_tests/verifier.c

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@@ -61,6 +61,7 @@
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#include "verifier_or_jmp32_k.skel.h"
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#include "verifier_precision.skel.h"
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#include "verifier_prevent_map_lookup.skel.h"
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#include "verifier_private_stack.skel.h"
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#include "verifier_raw_stack.skel.h"
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#include "verifier_raw_tp_writable.skel.h"
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#include "verifier_reg_equal.skel.h"
@@ -188,6 +189,7 @@ void test_verifier_bpf_fastcall(void) { RUN(verifier_bpf_fastcall); }
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void test_verifier_or_jmp32_k(void) { RUN(verifier_or_jmp32_k); }
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void test_verifier_precision(void) { RUN(verifier_precision); }
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void test_verifier_prevent_map_lookup(void) { RUN(verifier_prevent_map_lookup); }
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void test_verifier_private_stack(void) { RUN(verifier_private_stack); }
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void test_verifier_raw_stack(void) { RUN(verifier_raw_stack); }
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void test_verifier_raw_tp_writable(void) { RUN(verifier_raw_tp_writable); }
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void test_verifier_reg_equal(void) { RUN(verifier_reg_equal); }

‎tools/testing/selftests/bpf/progs/verifier_private_stack.c

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// SPDX-License-Identifier: GPL-2.0
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#include <vmlinux.h>
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#include <bpf/bpf_helpers.h>
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#include "bpf_misc.h"
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#include "bpf_experimental.h"
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/* From include/linux/filter.h */
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#define MAX_BPF_STACK 512
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#if defined(__TARGET_ARCH_x86)
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struct elem {
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struct bpf_timer t;
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char pad[256];
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};
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, 1);
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__type(key, int);
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__type(value, struct elem);
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} array SEC(".maps");
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SEC("kprobe")
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__description("Private stack, single prog")
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__success
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__arch_x86_64
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__jited(" movabsq $0x{{.*}}, %r9")
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__jited(" addq %gs:0x{{.*}}, %r9")
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__jited(" movl $0x2a, %edi")
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__jited(" movq %rdi, -0x100(%r9)")
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__naked void private_stack_single_prog(void)
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{
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asm volatile (" \
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r1 = 42; \
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*(u64 *)(r10 - 256) = r1; \
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r0 = 0; \
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exit; \
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" ::: __clobber_all);
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}
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SEC("raw_tp")
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__description("No private stack")
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__success
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__arch_x86_64
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__jited(" subq $0x8, %rsp")
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__naked void no_private_stack_nested(void)
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{
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asm volatile (" \
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r1 = 42; \
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*(u64 *)(r10 - 8) = r1; \
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r0 = 0; \
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exit; \
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" ::: __clobber_all);
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}
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__used
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__naked static void cumulative_stack_depth_subprog(void)
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{
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asm volatile (" \
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r1 = 41; \
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*(u64 *)(r10 - 32) = r1; \
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call %[bpf_get_smp_processor_id]; \
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exit; \
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" :
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: __imm(bpf_get_smp_processor_id)
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: __clobber_all);
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}
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SEC("kprobe")
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__description("Private stack, subtree > MAX_BPF_STACK")
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__success
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__arch_x86_64
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/* private stack fp for the main prog */
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__jited(" movabsq $0x{{.*}}, %r9")
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__jited(" addq %gs:0x{{.*}}, %r9")
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__jited(" movl $0x2a, %edi")
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__jited(" movq %rdi, -0x200(%r9)")
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__jited(" pushq %r9")
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__jited(" callq 0x{{.*}}")
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__jited(" popq %r9")
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__jited(" xorl %eax, %eax")
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__naked void private_stack_nested_1(void)
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{
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asm volatile (" \
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r1 = 42; \
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*(u64 *)(r10 - %[max_bpf_stack]) = r1; \
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call cumulative_stack_depth_subprog; \
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r0 = 0; \
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exit; \
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" :
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: __imm_const(max_bpf_stack, MAX_BPF_STACK)
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: __clobber_all);
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}
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__naked __noinline __used
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static unsigned long loop_callback(void)
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{
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asm volatile (" \
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call %[bpf_get_prandom_u32]; \
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r1 = 42; \
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*(u64 *)(r10 - 512) = r1; \
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call cumulative_stack_depth_subprog; \
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r0 = 0; \
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exit; \
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" :
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: __imm(bpf_get_prandom_u32)
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: __clobber_common);
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}
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SEC("raw_tp")
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__description("Private stack, callback")
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__success
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__arch_x86_64
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/* for func loop_callback */
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__jited("func #1")
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__jited(" endbr64")
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__jited(" nopl (%rax,%rax)")
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__jited(" nopl (%rax)")
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__jited(" pushq %rbp")
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__jited(" movq %rsp, %rbp")
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__jited(" endbr64")
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__jited(" movabsq $0x{{.*}}, %r9")
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__jited(" addq %gs:0x{{.*}}, %r9")
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__jited(" pushq %r9")
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__jited(" callq")
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__jited(" popq %r9")
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__jited(" movl $0x2a, %edi")
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__jited(" movq %rdi, -0x200(%r9)")
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__jited(" pushq %r9")
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__jited(" callq")
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__jited(" popq %r9")
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__naked void private_stack_callback(void)
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{
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asm volatile (" \
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r1 = 1; \
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r2 = %[loop_callback]; \
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r3 = 0; \
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r4 = 0; \
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call %[bpf_loop]; \
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r0 = 0; \
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exit; \
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" :
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: __imm_ptr(loop_callback),
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__imm(bpf_loop)
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: __clobber_common);
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}
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SEC("fentry/bpf_fentry_test9")
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__description("Private stack, exception in main prog")
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__success __retval(0)
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__arch_x86_64
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__jited(" pushq %r9")
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__jited(" callq")
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__jited(" popq %r9")
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int private_stack_exception_main_prog(void)
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{
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asm volatile (" \
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r1 = 42; \
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*(u64 *)(r10 - 512) = r1; \
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" ::: __clobber_common);
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bpf_throw(0);
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return 0;
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}
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__used static int subprog_exception(void)
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{
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bpf_throw(0);
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return 0;
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}
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SEC("fentry/bpf_fentry_test9")
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__description("Private stack, exception in subprog")
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__success __retval(0)
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__arch_x86_64
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__jited(" movq %rdi, -0x200(%r9)")
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__jited(" pushq %r9")
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__jited(" callq")
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__jited(" popq %r9")
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int private_stack_exception_sub_prog(void)
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{
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asm volatile (" \
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r1 = 42; \
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*(u64 *)(r10 - 512) = r1; \
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call subprog_exception; \
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" ::: __clobber_common);
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return 0;
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}
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int glob;
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__noinline static void subprog2(int *val)
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{
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glob += val[0] * 2;
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}
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__noinline static void subprog1(int *val)
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{
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int tmp[64] = {};
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tmp[0] = *val;
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subprog2(tmp);
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}
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__noinline static int timer_cb1(void *map, int *key, struct bpf_timer *timer)
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{
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subprog1(key);
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return 0;
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}
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__noinline static int timer_cb2(void *map, int *key, struct bpf_timer *timer)
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{
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return 0;
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}
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SEC("fentry/bpf_fentry_test9")
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__description("Private stack, async callback, not nested")
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__success __retval(0)
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__arch_x86_64
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__jited(" movabsq $0x{{.*}}, %r9")
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int private_stack_async_callback_1(void)
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{
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struct bpf_timer *arr_timer;
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int array_key = 0;
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arr_timer = bpf_map_lookup_elem(&array, &array_key);
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if (!arr_timer)
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return 0;
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bpf_timer_init(arr_timer, &array, 1);
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bpf_timer_set_callback(arr_timer, timer_cb2);
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bpf_timer_start(arr_timer, 0, 0);
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subprog1(&array_key);
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return 0;
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}
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SEC("fentry/bpf_fentry_test9")
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__description("Private stack, async callback, potential nesting")
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__success __retval(0)
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__arch_x86_64
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__jited(" subq $0x100, %rsp")
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int private_stack_async_callback_2(void)
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{
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struct bpf_timer *arr_timer;
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int array_key = 0;
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arr_timer = bpf_map_lookup_elem(&array, &array_key);
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if (!arr_timer)
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return 0;
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bpf_timer_init(arr_timer, &array, 1);
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bpf_timer_set_callback(arr_timer, timer_cb1);
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bpf_timer_start(arr_timer, 0, 0);
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subprog1(&array_key);
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return 0;
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}
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#else
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SEC("kprobe")
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__description("private stack is not supported, use a dummy test")
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__success
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int dummy_test(void)
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{
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return 0;
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}
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#endif
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char _license[] SEC("license") = "GPL";

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