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    SubjectRe: [PATCH] perf-script: check session->header.env.arch before using it
    Em Sun, Oct 03, 2021 at 10:32:38PM -0700, Song Liu escreveu:
    > When perf.data is not written cleanly, we would like to process existing
    > data as much as possible (please see f_header.data.size == 0 condition
    > in perf_session__read_header). However, perf.data with partial data may
    > crash perf. Specifically, we see crash in perf-script for NULL
    > session->header.env.arch.
    >
    > Fix this by checking session->header.env.arch before using it to determine
    > native_arch. Also split the if condition so it is easier to read.
    >
    > Cc: stable@vger.kernel.org
    > Signed-off-by: Song Liu <songliubraving@fb.com>
    > ---
    > tools/perf/builtin-script.c | 13 +++++++++----
    > 1 file changed, 9 insertions(+), 4 deletions(-)
    >
    > diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
    > index 6211d0b84b7a6..7821f6740ac1d 100644
    > --- a/tools/perf/builtin-script.c
    > +++ b/tools/perf/builtin-script.c
    > @@ -4039,12 +4039,17 @@ int cmd_script(int argc, const char **argv)
    > goto out_delete;
    >
    > uname(&uts);
    > - if (data.is_pipe || /* assume pipe_mode indicates native_arch */
    > - !strcmp(uts.machine, session->header.env.arch) ||
    > - (!strcmp(uts.machine, "x86_64") &&
    > - !strcmp(session->header.env.arch, "i386")))
    > + if (data.is_pipe) /* assume pipe_mode indicates native_arch */
    > native_arch = true;
    >
    > + if (session->header.env.arch) {

    Shouldn't the above be:

    else if (session->header.env.arch) {

    ?

    > + if (!strcmp(uts.machine, session->header.env.arch))
    > + native_arch = true;
    > + else if (!strcmp(uts.machine, "x86_64") &&
    > + !strcmp(session->header.env.arch, "i386"))
    > + native_arch = true;
    > + }
    > +
    > script.session = session;
    > script__setup_sample_type(&script);
    >
    > --
    > 2.30.2

    --

    - Arnaldo

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