1. 25 Jul, 2018 38 commits
  2. 22 Jul, 2018 2 commits
    • Greg Kroah-Hartman's avatar
      Linux 4.14.57 · ecc160ec
      Greg Kroah-Hartman authored
      ecc160ec
    • Tejun Heo's avatar
      string: drop __must_check from strscpy() and restore strscpy() usages in cgroup · 779128d8
      Tejun Heo authored
      commit 08a77676 upstream.
      
      e7fd37ba ("cgroup: avoid copying strings longer than the buffers")
      converted possibly unsafe strncpy() usages in cgroup to strscpy().
      However, although the callsites are completely fine with truncated
      copied, because strscpy() is marked __must_check, it led to the
      following warnings.
      
        kernel/cgroup/cgroup.c: In function ‘cgroup_file_name’:
        kernel/cgroup/cgroup.c:1400:10: warning: ignoring return value of ‘strscpy’, declared with attribute warn_unused_result [-Wunused-result]
           strscpy(buf, cft->name, CGROUP_FILE_NAME_MAX);
      	       ^
      
      To avoid the warnings, 50034ed4 ("cgroup: use strlcpy() instead of
      strscpy() to avoid spurious warning") switched them to strlcpy().
      
      strlcpy() is worse than strlcpy() because it unconditionally runs
      strlen() on the source string, and the only reason we switched to
      strlcpy() here was because it was lacking __must_check, which doesn't
      reflect any material differences between the two function.  It's just
      that someone added __must_check to strscpy() and not to strlcpy().
      
      These basic string copy operations are used in variety of ways, and
      one of not-so-uncommon use cases is safely handling truncated copies,
      where the caller naturally doesn't care about the return value.  The
      __must_check doesn't match the actual use cases and forces users to
      opt for inferior variants which lack __must_check by happenstance or
      spread ugly (void) casts.
      
      Remove __must_check from strscpy() and restore strscpy() usages in
      cgroup.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Suggested-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Cc: Ma Shimiao <mashimiao.fnst@cn.fujitsu.com>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Chris Metcalf <cmetcalf@ezchip.com>
      [backport only the string.h portion to remove build warnings starting to show up - gregkh]
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      779128d8