Re: [PATCH v2] perf annotate: Use jump__delete when freeing LoongArch jumps

[WANG Rui]

On Mon, Apr 13, 2026 at 6:11 PM Rong Bao <rong.bao@xxxxxxxxxxxx> wrote:
>
> Currently, the initialization of loongarch_jump_ops does not contain an
> assignment to its .free field. This causes disasm_line__free() to fall
> through to ins_ops__delete() for LoongArch jump instructions.
>
> ins_ops__delete() will free ins_operands.source.raw and
> ins_operands.source.name, and these fields overlaps with
> ins_operands.jump.raw_comment and ins_operands.jump.raw_func_start.
> Since in loongarch_jump__parse(), these two fields are populated by
> strchr()-ing the same buffer, trying to free them will lead to undefined
> behavior.
>
> This invalid free usually leads to crashes:
>
>         Process 1712902 (perf) of user 1000 dumped core.
>         Stack trace of thread 1712902:
>         #0  0x00007fffef155c58 n/a (libc.so.6 + 0x95c58)
>         #1  0x00007fffef0f7a94 raise (libc.so.6 + 0x37a94)
>         #2  0x00007fffef0dd6a8 abort (libc.so.6 + 0x1d6a8)
>         #3  0x00007fffef145490 n/a (libc.so.6 + 0x85490)
>         #4  0x00007fffef1646f4 n/a (libc.so.6 + 0xa46f4)
>         #5  0x00007fffef164718 n/a (libc.so.6 + 0xa4718)
>         #6  0x00005555583a6764 __zfree (/home/csmantle/dist/linux-arch/tools/perf/perf + 0x106764)
>         #7  0x000055555854fb70 disasm_line__free (/home/csmantle/dist/linux-arch/tools/perf/perf + 0x2afb70)
>         #8  0x000055555853d618 annotated_source__purge (/home/csmantle/dist/linux-arch/tools/perf/perf + 0x29d618)
>         #9  0x000055555852300c __hist_entry__tui_annotate (/home/csmantle/dist/linux-arch/tools/perf/perf + 0x28300c)
>         #10 0x0000555558526718 do_annotate (/home/csmantle/dist/linux-arch/tools/perf/perf + 0x286718)
>         #11 0x000055555852ed94 evsel__hists_browse (/home/csmantle/dist/linux-arch/tools/perf/perf + 0x28ed94)
>         #12 0x000055555831fdd0 cmd_report (/home/csmantle/dist/linux-arch/tools/perf/perf + 0x7fdd0)
>         #13 0x000055555839b644 handle_internal_command (/home/csmantle/dist/linux-arch/tools/perf/perf + 0xfb644)
>         #14 0x00005555582fe6ac main (/home/csmantle/dist/linux-arch/tools/perf/perf + 0x5e6ac)
>         #15 0x00007fffef0ddd90 n/a (libc.so.6 + 0x1dd90)
>         #16 0x00007fffef0ddf0c __libc_start_main (libc.so.6 + 0x1df0c)
>         #17 0x00005555582fed10 _start (/home/csmantle/dist/linux-arch/tools/perf/perf + 0x5ed10)
>         ELF object binary architecture: LoongArch
>
> ... and it can be confirmed with Valgrind:
>
>         ==1721834== Invalid free() / delete / delete[] / realloc()
>         ==1721834==    at 0x4EA9014: free (in /usr/lib/valgrind/vgpreload_memcheck-loongarch64-linux.so)
>         ==1721834==    by 0x4106287: __zfree (zalloc.c:13)
>         ==1721834==    by 0x42ADC8F: disasm_line__free (in /home/csmantle/dist/linux-arch/tools/perf/perf)
>         ==1721834==    by 0x429B737: annotated_source__purge (in /home/csmantle/dist/linux-arch/tools/perf/perf)
>         ==1721834==    by 0x42811EB: __hist_entry__tui_annotate (in /home/csmantle/dist/linux-arch/tools/perf/perf)
>         ==1721834==    by 0x42848D7: do_annotate (in /home/csmantle/dist/linux-arch/tools/perf/perf)
>         ==1721834==    by 0x428CF33: evsel__hists_browse (in /home/csmantle/dist/linux-arch/tools/perf/perf)
>         ==1721834==  Address 0x7d34303 is 35 bytes inside a block of size 62 alloc'd
>         ==1721834==    at 0x4EA59B8: malloc (in /usr/lib/valgrind/vgpreload_memcheck-loongarch64-linux.so)
>         ==1721834==    by 0x6B80B6F: strdup (strdup.c:42)
>         ==1721834==    by 0x42AD917: disasm_line__new (in /home/csmantle/dist/linux-arch/tools/perf/perf)
>         ==1721834==    by 0x42AE5A3: symbol__disassemble_objdump (in /home/csmantle/dist/linux-arch/tools/perf/perf)
>         ==1721834==    by 0x42AF0A7: symbol__disassemble (in /home/csmantle/dist/linux-arch/tools/perf/perf)
>         ==1721834==    by 0x429B3CF: symbol__annotate (in /home/csmantle/dist/linux-arch/tools/perf/perf)
>         ==1721834==    by 0x429C233: symbol__annotate2 (in /home/csmantle/dist/linux-arch/tools/perf/perf)
>         ==1721834==    by 0x42804D3: __hist_entry__tui_annotate (in /home/csmantle/dist/linux-arch/tools/perf/perf)
>         ==1721834==    by 0x42848D7: do_annotate (in /home/csmantle/dist/linux-arch/tools/perf/perf)
>         ==1721834==    by 0x428CF33: evsel__hists_browse (in /home/csmantle/dist/linux-arch/tools/perf/perf)
>
> This patch adds the missing free() specialization in loongarch_jump_ops,
> which prevents disasm_line__free() from invoking the default cleanup
> function.
>
> Fixes: fb7fd2a14a503b9a ("perf annotate: Move raw_comment and raw_func_start fields out of 'struct ins_operands'")
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: WANG Rui <wangrui@xxxxxxxxxxx>
> Cc: Huacai Chen <chenhuacai@xxxxxxxxxx>
> Cc: WANG Xuerui <kernel@xxxxxxxxxx>
> Cc: loongarch@xxxxxxxxxxxxxxx
> Signed-off-by: Rong Bao <rong.bao@xxxxxxxxxxxx>
> ---
> v1 -> v2: Correct "Fixes:" tag and move declaration of jump__delete()
>           per comments.
>
> v1: https://lore.kernel.org/lkml/20260412062828.1734637-1-rong.bao@xxxxxxxxxxxx
>
>  tools/perf/util/annotate-arch/annotate-loongarch.c | 1 +
>  tools/perf/util/disasm.c                           | 2 +-
>  tools/perf/util/disasm.h                           | 2 ++
>  3 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/annotate-arch/annotate-loongarch.c b/tools/perf/util/annotate-arch/annotate-loongarch.c
> index 950f34e59e5cd..c2addca77320b 100644
> --- a/tools/perf/util/annotate-arch/annotate-loongarch.c
> +++ b/tools/perf/util/annotate-arch/annotate-loongarch.c
> @@ -110,6 +110,7 @@ static int loongarch_jump__parse(const struct arch *arch, struct ins_operands *o
>  }
>
>  static const struct ins_ops loongarch_jump_ops = {
> +       .free      = jump__delete,
>         .parse     = loongarch_jump__parse,
>         .scnprintf = jump__scnprintf,
>         .is_jump   = true,
> diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c
> index 9e0420e14be19..62bd8c3e53051 100644
> --- a/tools/perf/util/disasm.c
> +++ b/tools/perf/util/disasm.c
> @@ -451,7 +451,7 @@ int jump__scnprintf(const struct ins *ins, char *bf, size_t size,
>                          ops->target.offset);
>  }
>
> -static void jump__delete(struct ins_operands *ops __maybe_unused)
> +void jump__delete(struct ins_operands *ops __maybe_unused)
>  {
>         /*
>          * The ops->jump.raw_comment and ops->jump.raw_func_start belong to the
> diff --git a/tools/perf/util/disasm.h b/tools/perf/util/disasm.h
> index a6e478caf61a9..25756e3f47e47 100644
> --- a/tools/perf/util/disasm.h
> +++ b/tools/perf/util/disasm.h
> @@ -161,6 +161,8 @@ int jump__scnprintf(const struct ins *ins, char *bf, size_t size,
>  int mov__scnprintf(const struct ins *ins, char *bf, size_t size,
>                    struct ins_operands *ops, int max_ins_name);
>
> +void jump__delete(struct ins_operands *ops);
> +
>  int symbol__disassemble(struct symbol *sym, struct annotate_args *args);
>
>  char *expand_tabs(char *line, char **storage, size_t *storage_len);
>
> base-commit: 028ef9c96e96197026887c0f092424679298aae8
> --
> 2.53.0
>
>

Tested-by: WANG Rui <wangrui@xxxxxxxxxxx>

Thanks,
Rui