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00387808d3
The change in struct file [1] moved f_ref to the 3rd cache line.
It made *(u64 *)file dereference invalid from the verifier point of view,
because btf_struct_walk() walks into f_lock field, which is 4-byte long.
Fix the selftests to deference the file pointer as a 4-byte access.
[1] commit e249056c91 ("fs: place f_ref to 3rd cache line in struct file to resolve false sharing")
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20250327185528.1740787-1-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
143 lines
3.3 KiB
C
143 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2020 Facebook */
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#include "vmlinux.h"
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_core_read.h>
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#include "../test_kmods/bpf_testmod.h"
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__u32 raw_tp_read_sz = 0;
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SEC("raw_tp/bpf_testmod_test_read")
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int BPF_PROG(handle_raw_tp,
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struct task_struct *task, struct bpf_testmod_test_read_ctx *read_ctx)
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{
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raw_tp_read_sz = BPF_CORE_READ(read_ctx, len);
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return 0;
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}
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__u32 raw_tp_bare_write_sz = 0;
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SEC("raw_tp/bpf_testmod_test_write_bare")
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int BPF_PROG(handle_raw_tp_bare,
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struct task_struct *task, struct bpf_testmod_test_write_ctx *write_ctx)
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{
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raw_tp_bare_write_sz = BPF_CORE_READ(write_ctx, len);
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return 0;
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}
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int raw_tp_writable_bare_in_val = 0;
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int raw_tp_writable_bare_early_ret = 0;
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int raw_tp_writable_bare_out_val = 0;
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SEC("raw_tp.w/bpf_testmod_test_writable_bare")
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int BPF_PROG(handle_raw_tp_writable_bare,
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struct bpf_testmod_test_writable_ctx *writable)
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{
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raw_tp_writable_bare_in_val = writable->val;
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writable->early_ret = raw_tp_writable_bare_early_ret;
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writable->val = raw_tp_writable_bare_out_val;
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return 0;
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}
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__u32 tp_btf_read_sz = 0;
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SEC("tp_btf/bpf_testmod_test_read")
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int BPF_PROG(handle_tp_btf,
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struct task_struct *task, struct bpf_testmod_test_read_ctx *read_ctx)
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{
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tp_btf_read_sz = read_ctx->len;
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return 0;
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}
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__u32 fentry_read_sz = 0;
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SEC("fentry/bpf_testmod_test_read")
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int BPF_PROG(handle_fentry,
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struct file *file, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf, loff_t off, size_t len)
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{
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fentry_read_sz = len;
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return 0;
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}
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__u32 fentry_manual_read_sz = 0;
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SEC("fentry")
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int BPF_PROG(handle_fentry_manual,
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struct file *file, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf, loff_t off, size_t len)
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{
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fentry_manual_read_sz = len;
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return 0;
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}
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__u32 fentry_explicit_read_sz = 0;
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SEC("fentry/bpf_testmod:bpf_testmod_test_read")
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int BPF_PROG(handle_fentry_explicit,
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struct file *file, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf, loff_t off, size_t len)
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{
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fentry_explicit_read_sz = len;
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return 0;
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}
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__u32 fentry_explicit_manual_read_sz = 0;
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SEC("fentry")
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int BPF_PROG(handle_fentry_explicit_manual,
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struct file *file, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf, loff_t off, size_t len)
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{
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fentry_explicit_manual_read_sz = len;
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return 0;
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}
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__u32 fexit_read_sz = 0;
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int fexit_ret = 0;
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SEC("fexit/bpf_testmod_test_read")
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int BPF_PROG(handle_fexit,
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struct file *file, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf, loff_t off, size_t len,
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int ret)
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{
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fexit_read_sz = len;
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fexit_ret = ret;
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return 0;
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}
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SEC("fexit/bpf_testmod_return_ptr")
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int BPF_PROG(handle_fexit_ret, int arg, struct file *ret)
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{
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long buf = 0;
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bpf_probe_read_kernel(&buf, 8, ret);
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bpf_probe_read_kernel(&buf, 8, (char *)ret + 256);
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*(volatile int *)ret;
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*(volatile int *)&ret->f_mode;
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return 0;
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}
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__u32 fmod_ret_read_sz = 0;
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SEC("fmod_ret/bpf_testmod_test_read")
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int BPF_PROG(handle_fmod_ret,
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struct file *file, struct kobject *kobj,
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struct bin_attribute *bin_attr, char *buf, loff_t off, size_t len)
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{
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fmod_ret_read_sz = len;
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return 0; /* don't override the exit code */
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}
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SEC("kprobe.multi/bpf_testmod_test_read")
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int BPF_PROG(kprobe_multi)
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{
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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