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bpf: Do not allocate percpu memory at init stage #662

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bpf: Do not allocate percpu memory at init stage #662

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2 changes: 1 addition & 1 deletion include/linux/bpf.h
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Original file line number Diff line number Diff line change
Expand Up @@ -56,7 +56,7 @@ extern struct idr btf_idr;
extern spinlock_t btf_idr_lock;
extern struct kobject *btf_kobj;
extern struct bpf_mem_alloc bpf_global_ma, bpf_global_percpu_ma;
extern bool bpf_global_ma_set, bpf_global_percpu_ma_set;
extern bool bpf_global_ma_set;

typedef u64 (*bpf_callback_t)(u64, u64, u64, u64, u64);
typedef int (*bpf_iter_init_seq_priv_t)(void *private_data,
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8 changes: 3 additions & 5 deletions kernel/bpf/core.c
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Expand Up @@ -64,8 +64,8 @@
#define OFF insn->off
#define IMM insn->imm

struct bpf_mem_alloc bpf_global_ma, bpf_global_percpu_ma;
bool bpf_global_ma_set, bpf_global_percpu_ma_set;
struct bpf_mem_alloc bpf_global_ma;
bool bpf_global_ma_set;

/* No hurry in this branch
*
Expand Down Expand Up @@ -2934,9 +2934,7 @@ static int __init bpf_global_ma_init(void)

ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false);
bpf_global_ma_set = !ret;
ret = bpf_mem_alloc_init(&bpf_global_percpu_ma, 0, true);
bpf_global_percpu_ma_set = !ret;
return !bpf_global_ma_set || !bpf_global_percpu_ma_set;
return ret;
}
late_initcall(bpf_global_ma_init);
#endif
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17 changes: 15 additions & 2 deletions kernel/bpf/verifier.c
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@
#include <linux/poison.h>
#include <linux/module.h>
#include <linux/cpumask.h>
#include <linux/bpf_mem_alloc.h>
#include <net/xdp.h>

#include "disasm.h"
Expand All @@ -41,6 +42,9 @@ static const struct bpf_verifier_ops * const bpf_verifier_ops[] = {
#undef BPF_LINK_TYPE
};

struct bpf_mem_alloc bpf_global_percpu_ma;
static bool bpf_global_percpu_ma_set;

/* bpf_check() is a static code analyzer that walks eBPF program
* instruction by instruction and updates register/stack state.
* All paths of conditional branches are analyzed until 'bpf_exit' insn.
Expand Down Expand Up @@ -12287,8 +12291,17 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
if (meta.func_id == special_kfunc_list[KF_bpf_obj_new_impl] && !bpf_global_ma_set)
return -ENOMEM;

if (meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl] && !bpf_global_percpu_ma_set)
return -ENOMEM;
if (meta.func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) {
mutex_lock(&bpf_verifier_lock);
if (!bpf_global_percpu_ma_set) {
err = bpf_mem_alloc_init(&bpf_global_percpu_ma, 0, true);
if (!err)
bpf_global_percpu_ma_set = true;
}
mutex_unlock(&bpf_verifier_lock);
if (err)
return err;
}

if (((u64)(u32)meta.arg_constant.value) != meta.arg_constant.value) {
verbose(env, "local type ID argument must be in range [0, U32_MAX]\n");
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