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    SubjectRe: [tip:perf/core] perf events: Fix false positive build warning with older GCC's
    tip-bot for Ingo Molnar wrote:
    > Commit-ID: 55632770d7298835645489828af87f854c47749c
    > Gitweb: http://git.kernel.org/tip/55632770d7298835645489828af87f854c47749c
    > Author: Ingo Molnar <mingo@elte.hu>
    > AuthorDate: Thu, 18 Mar 2010 16:51:16 +0100
    > Committer: Ingo Molnar <mingo@elte.hu>
    > CommitDate: Thu, 18 Mar 2010 17:03:24 +0100
    >
    > perf events: Fix false positive build warning with older GCC's
    >
    > gcc 4.2.1 produces:
    >
    > util/probe-event.c: In function 'add_perf_probe_events':
    > util/probe-event.c:883: warning: 'tev' may be used uninitialized in this function
    > make: *** [util/probe-event.o] Error 1
    >
    > Newer GCCs get this right.
    >
    > To work it around, initialize the variable to NULL so that older GCCs see
    > it as initialized too.

    Hmm, indeed. this code implies that ntevs > 0, it seems that we'd better
    check it first (e.g. 'if(ntevs <= 0) return;') too.

    Thank you,

    >
    > Cc: Masami Hiramatsu <mhiramat@redhat.com>
    > Cc: Frederic Weisbecker <fweisbec@gmail.com>
    > Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
    > Cc: Paul Mackerras <paulus@samba.org>
    > Cc: Mike Galbraith <efault@gmx.de>
    > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    > LKML-Reference: <20100316220612.32050.33806.stgit@localhost6.localdomain6>
    > Signed-off-by: Ingo Molnar <mingo@elte.hu>
    > ---
    > tools/perf/util/probe-event.c | 2 +-
    > 1 files changed, 1 insertions(+), 1 deletions(-)
    >
    > diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
    > index f333269..c6603f3 100644
    > --- a/tools/perf/util/probe-event.c
    > +++ b/tools/perf/util/probe-event.c
    > @@ -880,7 +880,7 @@ static void __add_kprobe_trace_events(struct perf_probe_event *pev,
    > int ntevs, bool allow_suffix)
    > {
    > int i, fd;
    > - struct kprobe_trace_event *tev;
    > + struct kprobe_trace_event *tev = NULL;
    > char buf[64];
    > const char *event, *group;
    > struct strlist *namelist;
    > --
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    --
    Masami Hiramatsu
    e-mail: mhiramat@redhat.com


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