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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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e626a13f6f
Drop bpf_iter.h header which uses vmlinux.h but re-defines a bunch of iterator structures and some of BPF constants for use in BPF iterator selftests. None of that is necessary when fresh vmlinux.h header is generated for vmlinux image that matches latest selftests. So drop ugly hacks and have a nice plain vmlinux.h usage everywhere. We could do the same with all the kfunc __ksym redefinitions, but that has dependency on very fresh pahole, so I'm not addressing that here. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20241029203919.1948941-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
125 lines
2.7 KiB
C
125 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
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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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char _license[] SEC("license") = "GPL";
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struct {
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__uint(type, BPF_MAP_TYPE_CGRP_STORAGE);
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__uint(map_flags, BPF_F_NO_PREALLOC);
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__type(key, int);
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__type(value, long);
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} map_a SEC(".maps");
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__s32 target_pid;
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__u64 cgroup_id;
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int target_hid;
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bool is_cgroup1;
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struct cgroup *bpf_task_get_cgroup1(struct task_struct *task, int hierarchy_id) __ksym;
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void bpf_cgroup_release(struct cgroup *cgrp) __ksym;
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void bpf_rcu_read_lock(void) __ksym;
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void bpf_rcu_read_unlock(void) __ksym;
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SEC("?iter.s/cgroup")
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int cgroup_iter(struct bpf_iter__cgroup *ctx)
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{
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struct cgroup *cgrp = ctx->cgroup;
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long *ptr;
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if (cgrp == NULL)
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return 0;
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ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0,
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BPF_LOCAL_STORAGE_GET_F_CREATE);
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if (ptr)
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cgroup_id = cgrp->kn->id;
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return 0;
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}
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static void __no_rcu_lock(struct cgroup *cgrp)
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{
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long *ptr;
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/* Note that trace rcu is held in sleepable prog, so we can use
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* bpf_cgrp_storage_get() in sleepable prog.
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*/
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ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0,
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BPF_LOCAL_STORAGE_GET_F_CREATE);
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if (ptr)
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cgroup_id = cgrp->kn->id;
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}
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SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
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int cgrp1_no_rcu_lock(void *ctx)
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{
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struct task_struct *task;
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struct cgroup *cgrp;
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task = bpf_get_current_task_btf();
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if (task->pid != target_pid)
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return 0;
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/* bpf_task_get_cgroup1 can work in sleepable prog */
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cgrp = bpf_task_get_cgroup1(task, target_hid);
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if (!cgrp)
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return 0;
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__no_rcu_lock(cgrp);
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bpf_cgroup_release(cgrp);
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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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int no_rcu_lock(void *ctx)
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{
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struct task_struct *task;
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task = bpf_get_current_task_btf();
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if (task->pid != target_pid)
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return 0;
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/* task->cgroups is untrusted in sleepable prog outside of RCU CS */
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__no_rcu_lock(task->cgroups->dfl_cgrp);
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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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int yes_rcu_lock(void *ctx)
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{
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struct task_struct *task;
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struct cgroup *cgrp;
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long *ptr;
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task = bpf_get_current_task_btf();
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if (task->pid != target_pid)
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return 0;
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if (is_cgroup1) {
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bpf_rcu_read_lock();
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cgrp = bpf_task_get_cgroup1(task, target_hid);
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if (!cgrp) {
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bpf_rcu_read_unlock();
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return 0;
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}
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ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, BPF_LOCAL_STORAGE_GET_F_CREATE);
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if (ptr)
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cgroup_id = cgrp->kn->id;
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bpf_cgroup_release(cgrp);
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bpf_rcu_read_unlock();
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return 0;
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}
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bpf_rcu_read_lock();
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cgrp = task->cgroups->dfl_cgrp;
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/* cgrp is trusted under RCU CS */
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ptr = bpf_cgrp_storage_get(&map_a, cgrp, 0, BPF_LOCAL_STORAGE_GET_F_CREATE);
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if (ptr)
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cgroup_id = cgrp->kn->id;
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bpf_rcu_read_unlock();
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return 0;
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}
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