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| author | Yonghong Song <yonghong.song@linux.dev> | 2026-05-16 01:50:56 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-05-17 03:46:16 +0300 |
| commit | d1dbe443a0abb4ea3ec35a16e36efe6d3bbf72f6 (patch) | |
| tree | 9e23942f3600de6eec59956d7930199d3bd7000c | |
| parent | 0e2647792f60df746422d6089daf9d56945d5f91 (diff) | |
| download | linux-d1dbe443a0abb4ea3ec35a16e36efe6d3bbf72f6.tar.xz | |
bpf: Fix arg_track_join log to use sa prefix for stack arg slots
arg_track_join() logs state transitions at CFG merge points. For
stack arg slots (r >= MAX_BPF_REG), it printed "r11:", "r12:", etc.,
which is misleading since r11 is a special register (BPF_REG_PARAMS)
not meaningful to the user.
Fix it to print "sa0:", "sa1:", etc., matching the per-instruction
transition log in arg_track_log() which already uses the "sa" prefix.
Update the existing stack_arg_pruning_type_mismatch selftest to expect
the corrected format.
Fixes: 2af4e792773f ("bpf: Extend liveness analysis to track stack argument slots")
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20260515225056.823086-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | kernel/bpf/liveness.c | 4 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/verifier_stack_arg.c | 2 |
2 files changed, 4 insertions, 2 deletions
diff --git a/kernel/bpf/liveness.c b/kernel/bpf/liveness.c index 7f4a0e4c2c49..0aadfbae0acc 100644 --- a/kernel/bpf/liveness.c +++ b/kernel/bpf/liveness.c @@ -806,7 +806,9 @@ static bool arg_track_join(struct bpf_verifier_env *env, int idx, int target, in return true; verbose(env, "arg JOIN insn %d -> %d ", idx, target); - if (r >= 0) + if (r >= MAX_BPF_REG) + verbose(env, "sa%d: ", r - MAX_BPF_REG); + else if (r >= 0) verbose(env, "r%d: ", r); else verbose(env, "fp%+d: ", r * 8); diff --git a/tools/testing/selftests/bpf/progs/verifier_stack_arg.c b/tools/testing/selftests/bpf/progs/verifier_stack_arg.c index df0c3438529e..7e0ce5db28a0 100644 --- a/tools/testing/selftests/bpf/progs/verifier_stack_arg.c +++ b/tools/testing/selftests/bpf/progs/verifier_stack_arg.c @@ -117,7 +117,7 @@ __description("stack_arg: pruning with different stack arg types") __failure __log_level(2) __flag(BPF_F_TEST_STATE_FREQ) __msg("arg JOIN insn 9 -> 10 r1: fp0-8 + _ => fp0-8|fp0+0") -__msg("arg JOIN insn 9 -> 10 r11: fp0-8 + _ => fp0-8|fp0+0") +__msg("arg JOIN insn 9 -> 10 sa0: fp0-8 + _ => fp0-8|fp0+0") __msg("R{{[0-9]}} invalid mem access 'scalar'") __naked void stack_arg_pruning_type_mismatch(void) { |