Hi Russell, Russell King - ARM Linux writes: > On Fri, Oct 05, 2018 at 10:46:19AM +0100, Russell King - ARM Linux wrote: >> On Fri, Oct 05, 2018 at 11:09:40AM +0200, Marek Szyprowski wrote: >> > This patch causes lots of kernel 'BUG' messages on all Samsung Exynos >> > boards. It started to appear since it has been merged to linux-next >> > on 20181002. I wonder if this issue is Exynos specific or there are >> > some patches missing in linux-next, which should fix those 'BUGS'. >> > If this is Exynos specific, please let us know what should be changed >> > in Exynos platform code to avoid this issue. >> >> Thanks for the report. >> >> It looks like my solution for big.Little isn't possible... back to >> the drawing board, and big.Little will have to remain vulnerable to >> Spectre for another release cycle. > > I've pushed out a new version in my build branch for the autobuilders > to chew on, but I've little confidence in validating that the problem > is fixed because the boot results are completely unreliable. > > It really doesn't help that kernelci.org flags boot logs as "green" > and "successful" when they contain such stuff as: > > 01:08:40.181846 [ 9.309984] Unable to handle kernel paging request at virtual address e7fddef0 > > which is the kernel hitting a BUG() - for the full log, see: > > https://storage.kernelci.org/rmk/to-build/v4.16-38-g9fa10446d304/arm/multi_v7_defconfig/lab-collabora/boot-exynos5800-peach-pi.html > > This means the only way to check is to _manually_ go through reading > each and every boot log - to see if your reported BUG: messages are > there - no thanks. You're right, we should be flagging these as boot failures. > If kernelci thinks that a boot which hits a kernel BUG(), but still > manages to get to a shell prompt is successful, it's giving very > misleading boot results. What about a WARN_ON() or an oops that > still allows it to reach a shell prompt. > > Yes, these may be "successful" in so far as reaching the shell prompt, > but they should at least be flagged for further inspection, not > effectively marked as "there is nothing wrong here". We currently catch stack bactraces like this, and flag them as boot warnings, and they are shown in the overview: https://kernelci.org/boot/id/5bd7af1b59b514ece774be08/ But, as you pointed out, that still requires knowing what you're looking for and manually digging for them as we con't have a good way of flagging them currently. What we need to do is catch both warnings (e.g. WARN_ON) etc. as well as real errors (e.g. BUG/panic/etc.). In the case of errors, we should mark the boot test as FAIL. Kevin
