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70bc793382
PT_REGS*() macro on some architectures force-cast struct pt_regs to
other types (user_pt_regs, etc) and might drop volatile modifiers, if any.
Volatile isn't really required as pt_regs value isn't supposed to change
during the BPF program run, so this is correct behavior.
But progs/loop3.c relies on that volatile modifier to ensure that loop
is preserved. Fix loop3.c by declaring i and sum variables as volatile
instead. It preserves the loop and makes the test pass on all
architectures (including s390x which is currently broken).
Fixes: 3cc31d7940 ("libbpf: Normalize PT_REGS_xxx() macro definitions")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220106205156.955373-1-andrii@kernel.org
24 lines
491 B
C
24 lines
491 B
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (c) 2019 Facebook
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#include <linux/sched.h>
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#include <linux/ptrace.h>
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#include <stdint.h>
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#include <stddef.h>
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#include <stdbool.h>
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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char _license[] SEC("license") = "GPL";
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SEC("raw_tracepoint/consume_skb")
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int while_true(struct pt_regs *ctx)
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{
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volatile __u64 i = 0, sum = 0;
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do {
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i++;
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sum += PT_REGS_RC(ctx);
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} while (i < 0x100000000ULL);
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return sum;
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}
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