Re: [PATCH 3/4] perf scripts: Add perf-stuck, to tell where a running perf is stuck

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] perf scripts: perf-dso GDB command fails on ASan/LSan builds
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commit 3e959f0b96fd50b6f00f007448b2245cac82c305
Author: Arnaldo Carvalho de Melo <acme@redhat.com>

perf scripts: Add perf-stuck, to tell where a running perf is stuck

This commit introduces a prototype perf-stuck script and accompanying GDB
script to identify where a running perf process is stuck. It samples /proc
entries and can optionally use GDB to dump the DWARF DIE chain.

> diff --git a/tools/perf/scripts/perf-stuck.gdb b/tools/perf/scripts/perf-stuck.gdb
> new file mode 100644
> index 0000000000000..2022f83c6bfdc
> --- /dev/null
> +++ b/tools/perf/scripts/perf-stuck.gdb
[ ... ]
> +define perf-dso
> +  if $_any_caller_is("find_data_type", 20)
> +    frame function find_data_type
> +    # REFCNT_CHECKING, implied by an ASan/LSan build, wraps struct map and
> +    # struct dso in a proxy keeping the real object in ->orig, so there the
> +    # dso is map->orig->dso->orig, giving map->orig->dso->orig->name here;
> +    # struct symbol is not wrapped, so sym->name needs no ->orig.
> +    printf "dso=%s ip=0x%lx sym=%s\n", dloc->ms->map->dso->name, dloc->ip, dloc->ms->sym ? dloc->ms->sym->name : "(no symbol)"

[Severity: Low]
Does this command fail on ASan/LSan builds? 

The comment correctly notes that REFCNT_CHECKING wraps struct map and struct
dso in a proxy requiring ->orig access, but the printf statement hardcodes
the standard non-ASan access path (dloc->ms->map->dso->name).

This causes the perf-dso GDB macro to fail to evaluate and abort when
running perf-stuck.sh -g against an ASan-instrumented perf process.

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Sashiko AI review · https://sashiko.dev/#/patchset/20260928220634.2451784-1-acme@kernel.org?part=3