deepin: ARM:Fix segmentation fault when running fuse-bpf on ARM

[myslqyr]

The Struct_op operation allocates a single memory page to store target platform binary code.On x86, where instruction lengths are shorter, one page is sufficient. However, on ARM architectures, longer instructions require more memory space, causing the single page allocation to overflow.

To resolve this, the memory allocation has been
increased to two pages, ensuring stable operation
of the fuse_daemon.

Summary by Sourcery

Increase the executable image buffer for BPF struct operations from one page to two pages to prevent overflows on architectures with longer instructions (e.g., ARM).

Bug Fixes:

• Prevent segmentation faults when running fuse-bpf on ARM by expanding the code buffer size for struct_ops.

Enhancements:

• Introduce ST_IMAGE_SIZE constant (PAGE_SIZE * 2) for consistent two-page allocations.
• Allocate two pages for the JIT-compiled image and adjust image_end accordingly.
• Update all set_memory_* calls to operate on two pages instead of one.

[sourcery-ai]

Reviewer's guide (collapsed on small PRs)

Reviewer's Guide

This patch defines a new ST_IMAGE_SIZE macro (2× PAGE_SIZE) and replaces hard-coded PAGE_SIZE values in buffer allocation, boundary checks, and memory protection calls to double the executable buffer for BPF struct operations, preventing overflows on architectures with larger instruction encodings.

Class diagram for updated bpf_struct_ops_map structure and related functions

classDiagram
    class bpf_struct_ops_map {
        +void *image
        +void *uvalue
        +struct bpf_links **links
    }
    class bpf_struct_ops_map_alloc {
        +bpf_struct_ops_map_alloc(union bpf_attr *attr)
    }
    class bpf_struct_ops_map_update_elem {
        +bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key, void *value, u64 flags)
    }
    bpf_struct_ops_map_alloc --> bpf_struct_ops_map : allocates
    bpf_struct_ops_map_update_elem --> bpf_struct_ops_map : updates
    bpf_struct_ops_map : image field now allocated with ST_IMAGE_SIZE (2 * PAGE_SIZE)

Loading

File-Level Changes

Change	Details	Files
Introduce ST_IMAGE_SIZE and replace PAGE_SIZE usage to double buffer size	Add #define ST_IMAGE_SIZE (PAGE_SIZE * 2) Use ST_IMAGE_SIZE instead of PAGE_SIZE in bpf_jit_alloc_exec() Update image_end calculation to ST_IMAGE_SIZE Adjust all set_memory_{rox,nx,rw} calls to use ST_IMAGE_SIZE / PAGE_SIZE	kernel/bpf/bpf_struct_ops.c

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[deepin-ci-robot]

Hi @myslqyr. Thanks for your PR. 😃

[deepin-ci-robot]

Hi @myslqyr. Thanks for your PR.

I'm waiting for a deepin-community member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[deepin-ci-robot]

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