libbpf: add compile-time OOB warning to bpf_tail_call_static #9659
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Add a compile-time check to bpf_tail_call_static() to warn when a
constant slot(index) is >= map->max_entries. This uses a small
BPF_MAP_ENTRIES() macro together with Clang's diagnose_if attribute.
Clang front-end keeps the map type with a '(*max_entries)[N]' field,
so the expression
sizeof(*(m)->max_entries) / sizeof(**(m)->max_entries)
is resolved to N entirely at compile time. This allows diagnose_if()
to emit a warning when a constant slot index is out of range.
Out-of-bounds tail call checkup is no-ops at runtime. Emitting a
compile-time warning can help developers detect mistakes earlier. The
check is currently limited to Clang (due to diagnose_if) and constant
indices, but should catch common errors.
Signed-off-by: Hoyeon Lee <[email protected]>
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Upstream branch: b338cf8 |
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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=999130 expired. Closing PR. |
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Pull request for series with
subject: libbpf: add compile-time OOB warning to bpf_tail_call_static
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=999130