[Deepin-Kernel-SIG] [linux 6.6-y] [Upstream] bpf: Charge modmem for struct_ops trampoline #1165
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mainline inclusion from mainline-v6.7-rc1 category: feature Current code charges modmem for regular trampoline, but not for struct_ops trampoline. Add bpf_jit_[charge|uncharge]_modmem() to struct_ops so the trampoline is charged in both cases. Signed-off-by: Song Liu <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Martin KaFai Lau <[email protected]> (cherry picked from commit 5c04433) Signed-off-by: Wentao Guan <[email protected]>
Reviewer's GuideIntroduce modmem charging and uncharging for struct_ops trampolines to match regular trampolines, updating allocation and free paths with proper error handling. Sequence diagram for struct_ops trampoline allocation and modmem chargingsequenceDiagram
participant Caller
participant "bpf_struct_ops_map_alloc()"
participant "bpf_jit_charge_modmem()"
participant "bpf_jit_alloc_exec()"
participant "bpf_jit_uncharge_modmem()"
participant "__bpf_struct_ops_map_free()"
Caller->>"bpf_struct_ops_map_alloc()": Request struct_ops map allocation
"bpf_struct_ops_map_alloc()"->>"bpf_jit_charge_modmem()": Charge modmem for trampoline
alt Charge fails
"bpf_struct_ops_map_alloc()"->>"__bpf_struct_ops_map_free()": Free resources
"bpf_struct_ops_map_alloc()"-->>Caller: Return error
else Charge succeeds
"bpf_struct_ops_map_alloc()"->>"bpf_jit_alloc_exec()": Allocate trampoline image
alt Allocation fails
"bpf_struct_ops_map_alloc()"->>"bpf_jit_uncharge_modmem()": Uncharge modmem
"bpf_struct_ops_map_alloc()"->>"__bpf_struct_ops_map_free()": Free resources
"bpf_struct_ops_map_alloc()"-->>Caller: Return error
else Allocation succeeds
"bpf_struct_ops_map_alloc()"-->>Caller: Return map
end
end
Sequence diagram for struct_ops trampoline free and modmem unchargingsequenceDiagram
participant Caller
participant "__bpf_struct_ops_map_free()"
participant "bpf_jit_free_exec()"
participant "bpf_jit_uncharge_modmem()"
Caller->>"__bpf_struct_ops_map_free()": Free struct_ops map
alt st_map->image exists
"__bpf_struct_ops_map_free()"->>"bpf_jit_free_exec()": Free trampoline image
"__bpf_struct_ops_map_free()"->>"bpf_jit_uncharge_modmem()": Uncharge modmem
end
"__bpf_struct_ops_map_free()"-->>Caller: Done
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[APPROVALNOTIFIER] This PR is NOT APPROVED This pull-request has been approved by: The full list of commands accepted by this bot can be found here.
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opsiff
changed the title
deepin pr auto review这段代码是关于BPF (Berkeley Packet Filter) struct_ops实现的部分修改，主要涉及到内存分配和释放的改进。我来对这段代码进行审查： 1. 语法逻辑代码语法正确，逻辑流程清晰。主要改进是将内存分配和释放的操作进行了更细致的处理，特别是对 2. 代码质量代码质量有所提升，主要表现在：
3. 代码性能性能方面没有明显变化，因为主要是对错误处理路径的改进，不会影响正常执行路径的性能。 4. 代码安全安全性的改进较为显著：
改进建议：
static void __bpf_struct_ops_map_free(struct bpf_map *map)
{
struct bpf_struct_ops_map *st_map = container_of(map, struct bpf_struct_ops_map, map);
if (st_map->image) {
bpf_jit_free_exec(st_map->image);
bpf_jit_uncharge_modmem(PAGE_SIZE);
}
if (st_map->links)
bpf_struct_ops_map_put_progs(st_map);
bpf_map_area_free(st_map->links);
bpf_map_area_free(st_map->uvalue);
bpf_map_area_free(st_map);
}
static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr)
{
struct bpf_struct_ops_map *st_map;
const struct btf_type *t, *vt;
struct bpf_map *map;
int ret;
st_ops = bpf_struct_ops_find_value(attr->btf_vmlinux_value_type_id);
if (!st_ops)
return ERR_PTR(-ENOENT);
t = st_ops->type;
vt = btf_type_by_id(st_ops->btf, st_ops->value_type_id);
if (!t || !vt)
return ERR_PTR(-EINVAL);
st_map = bpf_map_area_alloc(sizeof(*st_map), NUMA_NO_NODE);
if (!st_map)
return ERR_PTR(-ENOMEM);
st_map->st_ops = st_ops;
map = &st_map->map;
ret = bpf_jit_charge_modmem(PAGE_SIZE);
if (ret) {
bpf_map_area_free(st_map);
return ERR_PTR(ret);
}
st_map->image = bpf_jit_alloc_exec(PAGE_SIZE);
if (!st_map->image) {
bpf_jit_uncharge_modmem(PAGE_SIZE);
bpf_map_area_free(st_map);
return ERR_PTR(-ENOMEM);
}
st_map->uvalue = bpf_map_area_alloc(vt->size, NUMA_NO_NODE);
st_map->links = bpf_map_area_alloc(btf_type_vlen(t) * sizeof(struct bpf_links *), NUMA_NO_NODE);
if (!st_map->uvalue || !st_map->links) {
__bpf_struct_ops_map_free(map);
return ERR_PTR(-ENOMEM);
}
return map;
}这些改进可以使代码更加健壮，错误处理更加完善，同时保持代码的可读性和可维护性。 |
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Pull Request Overview
This PR backports a kernel patch from mainline v6.7-rc1 that adds proper module memory accounting for BPF struct_ops trampolines. Currently, modmem is charged for regular trampolines but not for struct_ops trampolines, creating an accounting inconsistency.
Key changes:
- Adds
bpf_jit_charge_modmem()call during struct_ops map allocation to account for trampoline memory - Adds
bpf_jit_uncharge_modmem()call during map cleanup to properly release the memory charge
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| st_map->image = bpf_jit_alloc_exec(PAGE_SIZE); | ||
| if (!st_map->image) { | ||
| /* __bpf_struct_ops_map_free() uses st_map->image as flag | ||
| * for "charged or not". In this case, we need to unchange |
There was a problem hiding this comment.
Corrected spelling of 'unchange' to 'uncharge'.
Suggested change
| * for "charged or not". In this case, we need to unchange | |
| * for "charged or not". In this case, we need to uncharge |
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mainline inclusion
from mainline-v6.7-rc1
category: feature
Current code charges modmem for regular trampoline, but not for struct_ops trampoline. Add bpf_jit_[charge|uncharge]_modmem() to struct_ops so the trampoline is charged in both cases.
Link: https://lore.kernel.org/r/[email protected]
(cherry picked from commit 5c04433)
Summary by Sourcery
Account for module memory usage in BPF struct_ops JIT trampolines by adding modmem charge and uncharge calls during allocation and free
New Features:
Enhancements: