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    Subject[PATCH 4.19 103/170] perf pmu: Suppress potential format-truncation warning
    Date
    4.19-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Ben Hutchings <ben@decadent.org.uk>

    commit 11a64a05dc649815670b1be9fe63d205cb076401 upstream.

    Depending on which functions are inlined in util/pmu.c, the snprintf()
    calls in perf_pmu__parse_{scale,unit,per_pkg,snapshot}() might trigger a
    warning:

    util/pmu.c: In function 'pmu_aliases':
    util/pmu.c:178:31: error: '%s' directive output may be truncated writing up to 255 bytes into a region of size between 0 and 4095 [-Werror=format-truncation=]
    snprintf(path, PATH_MAX, "%s/%s.unit", dir, name);
    ^~

    I found this when trying to build perf from Linux 3.16 with gcc 8.
    However I can reproduce the problem in mainline if I force
    __perf_pmu__new_alias() to be inlined.

    Suppress this by using scnprintf() as has been done elsewhere in perf.

    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: stable@vger.kernel.org
    Link: http://lkml.kernel.org/r/20181111184524.fux4taownc6ndbx6@decadent.org.uk
    Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    tools/perf/util/pmu.c | 8 ++++----
    1 file changed, 4 insertions(+), 4 deletions(-)

    --- a/tools/perf/util/pmu.c
    +++ b/tools/perf/util/pmu.c
    @@ -145,7 +145,7 @@ static int perf_pmu__parse_scale(struct
    int fd, ret = -1;
    char path[PATH_MAX];

    - snprintf(path, PATH_MAX, "%s/%s.scale", dir, name);
    + scnprintf(path, PATH_MAX, "%s/%s.scale", dir, name);

    fd = open(path, O_RDONLY);
    if (fd == -1)
    @@ -175,7 +175,7 @@ static int perf_pmu__parse_unit(struct p
    ssize_t sret;
    int fd;

    - snprintf(path, PATH_MAX, "%s/%s.unit", dir, name);
    + scnprintf(path, PATH_MAX, "%s/%s.unit", dir, name);

    fd = open(path, O_RDONLY);
    if (fd == -1)
    @@ -205,7 +205,7 @@ perf_pmu__parse_per_pkg(struct perf_pmu_
    char path[PATH_MAX];
    int fd;

    - snprintf(path, PATH_MAX, "%s/%s.per-pkg", dir, name);
    + scnprintf(path, PATH_MAX, "%s/%s.per-pkg", dir, name);

    fd = open(path, O_RDONLY);
    if (fd == -1)
    @@ -223,7 +223,7 @@ static int perf_pmu__parse_snapshot(stru
    char path[PATH_MAX];
    int fd;

    - snprintf(path, PATH_MAX, "%s/%s.snapshot", dir, name);
    + scnprintf(path, PATH_MAX, "%s/%s.snapshot", dir, name);

    fd = open(path, O_RDONLY);
    if (fd == -1)

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