On Sun, Mar 29, 2020 at 08:31:26PM +0900, Masahiro Yamada wrote: > On Fri, Mar 27, 2020 at 4:42 AM Nathan Chancellor > <natechancellor@xxxxxxxxx> wrote: > > > > Currently, we disable -Wtautological-compare, which in turn disables a > > bunch of more specific tautological comparison warnings that are useful > > for the kernel such as -Wtautological-bitwise-compare. See clang's > > documentation below for the other warnings that are suppressed by > > -Wtautological-compare. Now that all of the major/noisy warnings have > > been fixed, enable -Wtautological-compare so that more issues can be > > caught at build time by various continuous integration setups. > > > > -Wtautological-constant-out-of-range-compare is kept disabled under a > > normal build but visible at W=1 because there are places in the kernel > > where a constant or variable size can change based on the kernel > > configuration. These are not fixed in a clean/concise way and the ones > > I have audited so far appear to be harmless. It is not a subgroup but > > rather just one warning so we do not lose out on much coverage by > > default. > > > > Link: https://github.com/ClangBuiltLinux/linux/issues/488 > > Link: http://releases.llvm.org/10.0.0/tools/clang/docs/DiagnosticsReference.html#wtautological-compare > > Link: https://bugs.llvm.org/show_bug.cgi?id=42666 > > Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx> > > --- > > > > v1 -> v2: https://lore.kernel.org/lkml/20200219045423.54190-7-natechancellor@xxxxxxxxx/ > > > > * Expand commit message a bit by adding more reasoning behind change. > > * Disable -Wtautological-constant-out-of-range-compare under a normal > > build but allow it to show up at W=1 for easy auditing. > > > > I hope this can be accepted for 5.7. There are two warnings that I see > > still across a bunch of allyesconfig/allmodconfig builds that have > > patches sent but not accepted. I will ping them today. > > > > * https://lore.kernel.org/lkml/20191023002014.22571-1-natechancellor@xxxxxxxxx/ > > * https://lore.kernel.org/lkml/20200220051011.26113-1-natechancellor@xxxxxxxxx/ > > > OK, I will queue this up and send it to Linus > in the second week of MW. > > I hope all warnings will be fixed by that time. Just a follow up, those two patches have been picked up and should be in this coming release: https://git.kernel.org/balbi/usb/c/58582220d2d34228e5a1e1585e41b735713988bb https://git.kernel.org/rostedt/linux-trace/c/bf2cbe044da275021b2de5917240411a19e5c50d As of next-20200331, with the former applied (because it is not there yet) along with this patch, I see no warnings on arm, arm64, x86_64 all{mod,yes}config. Cheers, Nathan
