MaskRay added a comment. In D72222#1836645 <https://reviews.llvm.org/D72222#1836645>, @nickdesaulniers wrote:
> In D72222#1836610 <https://reviews.llvm.org/D72222#1836610>, @MaskRay wrote: > > > In D72222#1836409 <https://reviews.llvm.org/D72222#1836409>, @peter.smith > > wrote: > > > > > Although this particular commit will not be at fault, it is the option > > > that enables the feature which is the earliest I can bisect the fault to. > > > There are 3 files in linux that assert fail on the Implement the > > > 'patchable-function attribute'. The files in question are > > > kasan/quarantine.c, mm/slab_common.c and mm/slub.c . > > > > > > I reproduced with > > > > > > make CC=/path/to/clang/install/clang ARCH=arm64 > > > CROSS_COMPILE=aarch64-linux-gnu- HOSTGCC=gcc allmodconfig > > > > > > > > > You can get the log files for the build, which is from clang-10 > > > > > > https://git.linaro.org/toolchain/ci/base-artifacts.git/log/?h=linaro-local/ci/tcwg_kernel/llvm-release-aarch64-mainline-allmodconfig > > > (4: update: llvm-linux: 19676) > > > > > > If the patchable functions is intended for clang-10 we'll need to make > > > sure any fix is merged to clang-10. > > > > > > This commit was made before release/10.x branch. Maybe the easiest thing is > > to revert the driver change in release/10.x (CC @hans), before we had a > > better understanding of the problem. > > > If you have cycles to debug the assertions quickly, maybe it's a simple fix > that doesn't require a revert? > > > (Eventually I think the Linux kernel should have a better configure time > > test than a simple `whether the compiler accepts > > -fpatchable-function-entry=2,0?`) > > Maybe, but I would prefer to avoid such autoconf like detection. `cc-option` > in the kernel is relatively simple and hardened at this point. I will need to read your other qemu command lines to learn how to debug. The problem may be that the Linux kernel expects a different behavior from Clang's. We don't have to be hurry. If we decide to revert it in release/10.x, we can do that just a few days before 10.0.0 is released. (That was why I separated these patches...) I am more concerned of whether the GCC side will eventually fix the flaws (https://gcc.gnu.org/ml/gcc/2020-01/msg00067.html). (I really dislike how the feature was developed on the GCC side. Yet another Linux-kernel specific GCC option when there are already 4 existing options for the same feature) Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D72222/new/ https://reviews.llvm.org/D72222 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
