On Fri, Feb 14, 2020 at 01:10:26AM +0100, Thomas Gleixner wrote: > Josh Poimboeuf <jpoimboe@xxxxxxxxxx> writes: > > On Tue, Feb 11, 2020 at 12:47:38PM -0000, tip-bot2 for Josh Poimboeuf wrote: > >> The following commit has been merged into the core/objtool branch of tip: > >> > >> Commit-ID: 644592d328370af4b3e027b7b1ae9f81613782d8 > >> Gitweb: https://git.kernel.org/tip/644592d328370af4b3e027b7b1ae9f81613782d8 > >> Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> > >> AuthorDate: Mon, 10 Feb 2020 12:32:38 -06:00 > >> Committer: Borislav Petkov <bp@xxxxxxx> > >> CommitterDate: Tue, 11 Feb 2020 13:27:03 +01:00 > >> > >> objtool: Fail the kernel build on fatal errors > >> > >> When objtool encounters a fatal error, it usually means the binary is > >> corrupt or otherwise broken in some way. Up until now, such errors were > >> just treated as warnings which didn't fail the kernel build. > >> > >> However, objtool is now stable enough that if a fatal error is > >> discovered, it most likely means something is seriously wrong and it > >> should fail the kernel build. > >> > >> Note that this doesn't apply to "normal" objtool warnings; only fatal > >> ones. > > > > Clang still has some toolchain issues which need to be sorted out, so > > upgrading the fatal errors is causing their CI to fail. > > Good. Last time we made it fail they just fixed their stuff. > > > So I think we need to drop this one for now. > > Why? It's our decision to define which level of toolchain brokeness is > tolerable. > > > Boris, are you able to just drop it or should I send a revert? > > I really want to see a revert which has a proper justification why the > issues of clang are tolerable along with a clear statement when this > fatal error will come back. And 'when' means a date, not 'when clang is > fixed'. Fair enough. The root cause was actually a bug in binutils which gets triggered by a new clang feature. So instead of reverting the above patch, I think I've figured out a way to work around the binutils bug, while also improving objtool at the same time (win-win). The binutils bug will be fixed in binutils 2.35. BTW, to be fair, this was less "Clang has issues" and more "Josh is lazy". I didn't test the patch with Clang -- I tend to rely on 0-day bot reports because I don't have the bandwidth to test the kernel/config/toolchain combinations. Nick tells me Clang will soon be integrated with the 0-day bot, which should help prevent this type of thing in the future. -- Josh
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