bpf: Show more useful info in stack depth stats

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Stack depth statistics list captured depths in subprogram-number order,
while per-verification instruction counts are reported separately. Since
libbpf determines subprogram numbers, it is hard to associate either
statistic with its subprogram name or see where verifier work is spent.

Now that self and inclusive instruction counts are available for every
subprogram, keep the combined maximum stack depth on its own line and print
one uniform record for each subprogram. Represent the main program as
subprog 0, then classify each record as main, global, or static before
reporting insns_self, insns_total, and stack depth.

The aggregate processed count is the sum of all self counts, while each
total shows verifier work rooted at that subprogram.

When no subprogram name is available, print <unknown>. Keep the existing
aggregate "processed ... insns" record unchanged for compatibility.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/20260812221925.3358041-4-memxor@gmail.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>

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Kumar Kartikeya Dwivedi 2026-08-13 00:19:20 +02:00 • committed by Eduard Zingerman

parent 6137fb7c5f

commit c2e6c7de88

6 changed files with 58 additions and 25 deletions

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23

kernel/bpf/verifier.c

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6

tools/testing/selftests/bpf/progs/verifier_basic_stack.c

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28

tools/testing/selftests/bpf/progs/verifier_bpf_fastcall.c

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5

tools/testing/selftests/bpf/progs/verifier_global_subprogs.c

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15

tools/testing/selftests/bpf/progs/verifier_private_stack.c

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6

tools/testing/selftests/bpf/progs/verifier_var_off.c

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