• Matteo Croce's avatar
    samples, bpf: suppress compiler warning · 3ab0e4bc
    Matteo Croce authored
    [ Upstream commit a195ceff ]
    
    GCC 9 fails to calculate the size of local constant strings and produces a
    false positive:
    
    samples/bpf/task_fd_query_user.c: In function ‘test_debug_fs_uprobe’:
    samples/bpf/task_fd_query_user.c:242:67: warning: ‘%s’ directive output may be truncated writing up to 255 bytes into a region of size 215 [-Wformat-truncation=]
      242 |  snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%ss/%s/id",
          |                                                                   ^~
      243 |    event_type, event_alias);
          |                ~~~~~~~~~~~
    samples/bpf/task_fd_query_user.c:242:2: note: ‘snprintf’ output between 45 and 300 bytes into a destination of size 256
      242 |  snprintf(buf, sizeof(buf), "/sys/kernel/debug/tracing/events/%ss/%s/id",
          |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      243 |    event_type, event_alias);
          |    ~~~~~~~~~~~~~~~~~~~~~~~~
    
    Workaround this by lowering the buffer size to a reasonable value.
    Related GCC Bugzilla: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83431Signed-off-by: default avatarMatteo Croce <mcroce@redhat.com>
    Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
    Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
    3ab0e4bc
task_fd_query_user.c 10.5 KB