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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138// SPDX-License-Identifier: GPL-2.0/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */
#include <vmlinux.h>#include <bpf/bpf_helpers.h>#include "../test_kmods/bpf_testmod_kfunc.h"#include "bpf_misc.h"
#if (defined(__TARGET_ARCH_x86) || defined(__TARGET_ARCH_arm64) || \ (defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64)) && \ defined(__BPF_FEATURE_STACK_ARGUMENT)
/* Force kfunc extern BTF generation for inline asm call below. * Uses its own SEC so it's not included as a .text subprog. * The '?' prefix sets autoload=false so libbpf won't load it. */SEC("?tc")int __btf_kfunc_gen(struct __sk_buff *ctx){ char buf[8] = {};
return bpf_kfunc_call_stack_arg_mem(0, 0, 0, 0, 0, buf, sizeof(buf));}
/* * Test precision backtracking across bpf-to-bpf call for kfunc stack arg. * subprog_call_mem_kfunc receives a size as incoming stack arg (arg6) * and forwards it as mem__sz (arg7) to bpf_kfunc_call_stack_arg_mem. */__naked __noinline __usedstatic long subprog_call_mem_kfunc(long a, long b, long c, long d, long e, long size){ asm volatile ( "r1 = *(u64 *)(r11 + 8);" /* r1 = incoming arg6 (size) */ "r2 = 0x0807060504030201 ll;" /* r2 = buf contents */ "*(u64 *)(r10 - 8) = r2;" /* store buf to stack */ "r2 = r10;" "r2 += -8;" /* r2 = &buf */ "*(u64 *)(r11 - 8) = r2;" /* outgoing arg6 = buf */ "*(u64 *)(r11 - 16) = r1;" /* outgoing arg7 = size */ "r1 = 1;" "r2 = 2;" "r3 = 3;" "r4 = 4;" "r5 = 5;" "call %[bpf_kfunc_call_stack_arg_mem];" "exit;" : : __imm(bpf_kfunc_call_stack_arg_mem) : __clobber_all );}
SEC("tc")__description("stack_arg: precision backtracking across bpf2bpf call for kfunc")__success__log_level(2)__flag(BPF_F_TEST_STATE_FREQ)__btf_func_path("btf__stack_arg_precision.bpf.o")__msg("mark_precise: frame1: last_idx 26 first_idx 13 subseq_idx -1")__msg("mark_precise: frame1: regs= stack= before 25: (b7) r5 = 5")__msg("mark_precise: frame1: regs= stack= before 24: (b7) r4 = 4")__msg("mark_precise: frame1: regs= stack= before 23: (b7) r3 = 3")__msg("mark_precise: frame1: regs= stack= before 22: (b7) r2 = 2")__msg("mark_precise: frame1: regs= stack= before 21: (b7) r1 = 1")__msg("mark_precise: frame1: regs= stack= before 20: (7b) *(u64 *)(r11 -16) = r1")__msg("mark_precise: frame1: regs=r1 stack= before 19: (7b) *(u64 *)(r11 -8) = r2")__msg("mark_precise: frame1: regs=r1 stack= before 18: (07) r2 += -8")__msg("mark_precise: frame1: regs=r1 stack= before 17: (bf) r2 = r10")__msg("mark_precise: frame1: regs=r1 stack= before 16: (7b) *(u64 *)(r10 -8) = r2")__msg("mark_precise: frame1: regs=r1 stack= before 14: (18) r2 = 0x807060504030201")__msg("mark_precise: frame1: regs=r1 stack= before 13: (79) r1 = *(u64 *)(r11 +8)")__msg("mark_precise: frame1: parent state regs= stack=: frame1: R10=fp0")__msg("mark_precise: frame0: parent state regs= stack=: R10=fp0")__msg("mark_precise: frame1: last_idx 11 first_idx 11 subseq_idx 13")__msg("mark_precise: frame1: regs= stack= before 11: (85) call pc+1")__msg("mark_precise: frame0: parent state regs= stack=: R10=fp0")__msg("mark_precise: frame0: last_idx 9 first_idx 7 subseq_idx 11")__msg("mark_precise: frame0: regs= stack= before 9: (05) goto pc+1")__msg("mark_precise: frame0: regs= stack= before 8: (7a) *(u64 *)(r11 -8) = 4")__msg("mark_precise: frame1: last_idx 26 first_idx 13 subseq_idx -1 ")__msg("mark_precise: frame1: regs= stack= before 25: (b7) r5 = 5")__msg("mark_precise: frame1: regs= stack= before 24: (b7) r4 = 4")__msg("mark_precise: frame1: regs= stack= before 23: (b7) r3 = 3")__msg("mark_precise: frame1: regs= stack= before 22: (b7) r2 = 2")__msg("mark_precise: frame1: regs= stack= before 21: (b7) r1 = 1")__msg("mark_precise: frame1: regs= stack= before 20: (7b) *(u64 *)(r11 -16) = r1")__msg("mark_precise: frame1: regs=r1 stack= before 19: (7b) *(u64 *)(r11 -8) = r2")__msg("mark_precise: frame1: regs=r1 stack= before 18: (07) r2 += -8")__msg("mark_precise: frame1: regs=r1 stack= before 17: (bf) r2 = r10")__msg("mark_precise: frame1: regs=r1 stack= before 16: (7b) *(u64 *)(r10 -8) = r2")__msg("mark_precise: frame1: regs=r1 stack= before 14: (18) r2 = 0x807060504030201")__msg("mark_precise: frame1: regs=r1 stack= before 13: (79) r1 = *(u64 *)(r11 +8)")__msg("mark_precise: frame1: parent state regs= stack=: frame1: R10=fp0")__msg("mark_precise: frame0: parent state regs= stack=: R10=fp0")__msg("mark_precise: frame1: last_idx 11 first_idx 11 subseq_idx 13 ")__msg("mark_precise: frame1: regs= stack= before 11: (85) call pc+1")__msg("mark_precise: frame0: parent state regs= stack=: R10=fp0")__msg("mark_precise: frame0: last_idx 10 first_idx 10 subseq_idx 11 ")__msg("mark_precise: frame0: regs= stack= before 10: (7a) *(u64 *)(r11 -8) = 6")__naked void stack_arg_precision_bpf2bpf(void){ asm volatile ( "call %[bpf_get_prandom_u32];" "r6 = r0;" "r1 = 1;" "r2 = 2;" "r3 = 3;" "r4 = 4;" "r5 = 5;" "if r6 < 2 goto l0_%=;" "*(u64 *)(r11 - 8) = 4;" "goto l1_%=;" "l0_%=:" "*(u64 *)(r11 - 8) = 6;" "l1_%=:" "call subprog_call_mem_kfunc;" "exit;" :: __imm(bpf_get_prandom_u32) : __clobber_all );}
#else
SEC("socket")__description("stack_arg_precision: not supported, dummy test")__skip("stack_arg_precision: not supported")__successint dummy_test(void){ return 0;}
#endif
char _license[] SEC("license") = "GPL";