On 2025-03-24 at 11:43:27 +0100, Maciej Wieczor-Retman wrote: >On 2025-03-21 at 21:16:12 +0100, Andrey Konovalov wrote: >>On Fri, Mar 21, 2025 at 8:21 PM Maciej Wieczor-Retman >><maciej.wieczor-retman@xxxxxxxxx> wrote: >>> >>> >To account for this, let's then set hwasan-instrument-with-calls=0 >>> >when CONFIG_KASAN_INLINE is enabled. And also please add a comment >>> >explaining why this is done. >>> >>> After adding this option the kernel doesn't want to boot past uncompressing :b >>> >>> I went into Samuel's clang PR [1] and found there might be one more LShr that >>> needs changing into AShr [2]? But I'm not very good at clang code. Do you maybe >>> know if anything else in the clang code could be messing things up? >>> >>> After changing that LShr to AShr it moves a little further and hangs on some >>> initmem setup code. Then I thought my KASAN_SHADOW_OFFSET is an issue so I >>> changed to 4-level paging and the offset to 0xfffffc0000000000 and it moves a >>> little further and panics on kmem_cache_init. I'll be debugging that further but >>> just thought I'd ask if you know about something missing from the compiler side? >>> >>> [1] https://github.com/llvm/llvm-project/pull/103727 >>> [2] https://github.com/SiFiveHolland/llvm-project/blob/up/hwasan-opt/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp#L995 >> >>Hm, I only recall looking at the compiler code when investigating [1]. >>But as this series points out, [1] can be considered a feature and not >>a bug. Other than that, nothing comes to mind. >> >>Thanks! >> >>[1] https://bugzilla.kernel.org/show_bug.cgi?id=218043 > >So I assume that if outline mode works, inline mode should be fine as far as >kernel is concerned? If so perhaps it will be more time efficient to post v3 of >this series (once I'm done with kasan_non_canonical_hook() edge cases and >unpoisoning per-cpu vms[areas] with the same tag) and work on the clang side >later / in the meantime. Oh, I guess I also need to add a patch to handle the int3 (X86_TRAP_BP) so kasan reports show up in inline mode. -- Kind regards Maciej Wieczór-Retman
