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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>
52 lines
1.1 KiB
C
52 lines
1.1 KiB
C
// 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/bpf_tracing.h>
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, 8);
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__type(key, __u32);
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__type(value, __u64);
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} test_array SEC(".maps");
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unsigned int triggered;
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static __u64 test_cb(struct bpf_map *map, __u32 *key, __u64 *val, void *data)
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{
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return 1;
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}
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SEC("fexit/bpf_testmod_return_ptr")
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int BPF_PROG(handle_fexit_ret_subprogs, int arg, struct file *ret)
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{
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*(volatile int *)ret;
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*(volatile int *)&ret->f_mode;
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bpf_for_each_map_elem(&test_array, test_cb, NULL, 0);
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triggered++;
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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_subprogs2, int arg, struct file *ret)
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{
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*(volatile int *)ret;
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*(volatile int *)&ret->f_mode;
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bpf_for_each_map_elem(&test_array, test_cb, NULL, 0);
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triggered++;
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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_subprogs3, int arg, struct file *ret)
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{
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*(volatile int *)ret;
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*(volatile int *)&ret->f_mode;
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bpf_for_each_map_elem(&test_array, test_cb, NULL, 0);
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triggered++;
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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