bpf: Allow terminal gotox instructions

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check_subprogs() treats gotox as a direct jump and validates its reserved
zero offset. When gotox is the final instruction, this produces a
synthetic successor one instruction past the end of the subprogram and
rejects an otherwise valid program.

Skip direct-offset validation for gotox and accept it as a
non-fallthrough terminal instruction. Its actual targets remain validated
from the instruction-array jump table during CFG construction.

Fixes: 493d9e0d60 ("bpf, x86: add support for indirect jumps")
Signed-off-by: Siddharth Chintamaneni <sidchintamaneni@gmail.com>
Reviewed-by: Anton Protopopov <a.s.protopopov@gmail.com>
Link: https://lore.kernel.org/r/20260902171414.96165-1-sidchintamaneni@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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Siddharth Chintamaneni 2026-09-02 17:14:13 +00:00 • committed by Alexei Starovoitov

parent 15071f2a12

commit 0d7823cd4c

1 changed files with 4 additions and 1 deletions

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kernel/bpf/verifier.c

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