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[ Upstream commit bffdeaa ] BPF verifier marks some instructions as prune points. Currently these prune points serve two purposes. It's a point where verifier tries to find previously verified state and check current state's equivalence to short circuit verification for current code path. But also currently it's a point where jump history, used for precision backtracking, is updated. This is done so that non-linear flow of execution could be properly backtracked. Such coupling is coincidental and unnecessary. Some prune points are not part of some non-linear jump path, so don't need update of jump history. On the other hand, not all instructions which have to be recorded in jump history necessarily are good prune points. This patch splits prune and jump points into independent flags. Currently all prune points are marked as jump points to minimize amount of changes in this patch, but next patch will perform some optimization of prune vs jmp point placement. No functional changes are intended. Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20221206233345.438540-2-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Stable-dep-of: 3feb263 ("bpf: handle ldimm64 properly in check_cfg()") Signed-off-by: Sasha Levin <sashal@kernel.org>
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