8ec3bf5c31
Add bpf_guard_preempt() macro that uses newly introduced bpf_preempt_disable/enable() kfuncs to guard a critical section. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20240424225529.16782-1-alexei.starovoitov@gmail.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
132 lines
2.5 KiB
C
132 lines
2.5 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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#include "bpf_misc.h"
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#include "bpf_experimental.h"
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SEC("?tc")
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__failure __msg("1 bpf_preempt_enable is missing")
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int preempt_lock_missing_1(struct __sk_buff *ctx)
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{
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bpf_preempt_disable();
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return 0;
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}
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SEC("?tc")
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__failure __msg("2 bpf_preempt_enable(s) are missing")
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int preempt_lock_missing_2(struct __sk_buff *ctx)
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{
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bpf_preempt_disable();
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bpf_preempt_disable();
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return 0;
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}
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SEC("?tc")
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__failure __msg("3 bpf_preempt_enable(s) are missing")
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int preempt_lock_missing_3(struct __sk_buff *ctx)
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{
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bpf_preempt_disable();
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bpf_preempt_disable();
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bpf_preempt_disable();
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return 0;
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}
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SEC("?tc")
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__failure __msg("1 bpf_preempt_enable is missing")
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int preempt_lock_missing_3_minus_2(struct __sk_buff *ctx)
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{
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bpf_preempt_disable();
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bpf_preempt_disable();
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bpf_preempt_disable();
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bpf_preempt_enable();
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bpf_preempt_enable();
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return 0;
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}
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static __noinline void preempt_disable(void)
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{
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bpf_preempt_disable();
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}
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static __noinline void preempt_enable(void)
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{
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bpf_preempt_enable();
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}
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SEC("?tc")
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__failure __msg("1 bpf_preempt_enable is missing")
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int preempt_lock_missing_1_subprog(struct __sk_buff *ctx)
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{
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preempt_disable();
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return 0;
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}
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SEC("?tc")
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__failure __msg("2 bpf_preempt_enable(s) are missing")
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int preempt_lock_missing_2_subprog(struct __sk_buff *ctx)
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{
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preempt_disable();
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preempt_disable();
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return 0;
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}
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SEC("?tc")
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__failure __msg("1 bpf_preempt_enable is missing")
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int preempt_lock_missing_2_minus_1_subprog(struct __sk_buff *ctx)
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{
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preempt_disable();
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preempt_disable();
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preempt_enable();
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return 0;
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}
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static __noinline void preempt_balance_subprog(void)
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{
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preempt_disable();
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preempt_enable();
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}
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SEC("?tc")
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__success int preempt_balance(struct __sk_buff *ctx)
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{
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bpf_guard_preempt();
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return 0;
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}
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SEC("?tc")
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__success int preempt_balance_subprog_test(struct __sk_buff *ctx)
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{
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preempt_balance_subprog();
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return 0;
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}
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SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
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__failure __msg("sleepable helper bpf_copy_from_user#")
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int preempt_sleepable_helper(void *ctx)
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{
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u32 data;
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bpf_preempt_disable();
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bpf_copy_from_user(&data, sizeof(data), NULL);
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bpf_preempt_enable();
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return 0;
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}
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int __noinline preempt_global_subprog(void)
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{
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preempt_balance_subprog();
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return 0;
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}
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SEC("?tc")
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__failure __msg("global function calls are not allowed with preemption disabled")
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int preempt_global_subprog_test(struct __sk_buff *ctx)
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{
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preempt_disable();
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preempt_global_subprog();
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preempt_enable();
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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