On Mon, Feb 19, 2018 at 12:20 AM, David Rientjes <[email protected]> wrote: > On Sat, 17 Feb 2018, Miguel Ojeda wrote: > >> From the GCC manual: >> >> The nonstring variable attribute specifies that an object or member >> declaration with type array of char or pointer to char is intended to >> store character arrays that do not necessarily contain a terminating NUL >> character. This is useful in detecting uses of such arrays or pointers >> with functions that expect NUL-terminated strings, and to avoid warnings >> when such an array or pointer is used as an argument to a bounded string >> manipulation function such as strncpy. >> >> https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html >> >> Some reports are already coming to the LKML regarding these >> warnings. When they are false positives, we can use __nonstring to let >> gcc know a NUL character is not required; like in this case: >> >> https://lkml.org/lkml/2018/1/16/135 >> >> Signed-off-by: Miguel Ojeda <[email protected]> >> Cc: Ingo Molnar <[email protected]> >> Cc: Josh Poimboeuf <[email protected]> >> Cc: Kees Cook <[email protected]> >> Cc: Andrew Morton <[email protected]> >> Cc: Geert Uytterhoeven <[email protected]> >> Cc: Will Deacon <[email protected]> >> Cc: Greg Kroah-Hartman <[email protected]> >> Cc: David Rientjes <[email protected]> > > I would have expected to have seen __nonstring used somewhere as part of > this patch.
Do you mean to expand the commit message with an actual code example instead of the links to the docs and the discussion about the report? Otherwise, if you mean in the actual commit, I think in that case it should be a patch series, not a single commit. In any case, the key point here is to agree on the short-term policy: i.e. whether we want to disable the upcoming warning or try to take advantage of it (which not *necessarily* implies using __nonstring, there are other workarounds; though where applicable, __nonstring is probably the right thing to use). [By the way, CC'ing Xiongfeng, Willy and Arnd, since they were involved in the example report; sorry guys!]. Cheers, Miguel
