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selftests/bpf: Fix chained_global_func_calls_success() for cpu v4

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The chained_global_func_calls_success() test hardcodes the instruction
counts reported by the verifier's per-subprog stats:

  subprog {{[0-9]+}} (global_good) global insns_self 5 insns_total 5 stack
  processed 14 insns

global_good() does 'return arr[0]', where arr[] is an int array and the
return type is long. Without cpu v4 this is a zero-extending load
followed by a <<32/s>>32 sign-extension pair. With -mcpu=v4 llvm emits a
single sign-extending load instead:

  18: (18) r1 = 0xffa00000008eb000
  20: (81) r0 = *(s32 *)(r1 +0)
  21: (95) exit

so the subprog is 3 insns rather than 5, and the whole program is
12 processed insns rather than 14. test_progs-cpuv4 fails with:

  EXPECTED    REGEX: 'subprog {{[0-9]+}} (global_good) global insns_self 5 insns_total 5 stack'
  #606/1   verifier_global_subprogs/chained_global_func_calls_success:FAIL

Select the expected counts based on __BPF_CPU_VERSION__.

Fixes: c2e6c7de88 ("bpf: Show more useful info in stack depth stats")
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20260813150641.3347662-1-yonghong.song@linux.dev
This commit is contained in:
Yonghong Song
2026-08-13 08:06:41 -07:00
committed by Daniel Borkmann
parent 6f033615ef
commit 9786d424a3
1 changed files with 5 additions and 0 deletions
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5
tools/testing/selftests/bpf/progs/verifier_global_subprogs.c
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@@ -54,8 +54,13 @@ __msg("Validating global_good() func")
__msg("('global_good') is safe for any args that match its prototype")
__msg("subprog 0 (chained_global_func_calls_success) main insns_self 7 insns_total 7 stack")
__msg("subprog {{[0-9]+}} (global_calls_good_only) global insns_self 2 insns_total 2 stack")
#if defined(__BPF_CPU_VERSION__) && __BPF_CPU_VERSION__ >= 4
__msg("subprog {{[0-9]+}} (global_good) global insns_self 3 insns_total 3 stack")
__msg("processed 12 insns")
#else
__msg("subprog {{[0-9]+}} (global_good) global insns_self 5 insns_total 5 stack")
__msg("processed 14 insns")
#endif
int chained_global_func_calls_success(void)
{
int sum = 0;