Buildresult: linus/x86_64-defconfig/x86_64-gcc8 built on Feb 10, 13:10

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Status:	OK
Date/Time:	Feb 10, 13:10
Duration:	0:01:33.166013
Builder:	ka4
Revision:	work around gcc bugs with 'asm goto' with outputs (`4356e9f841f7fbb945521cef3577ba394c65f3fc)`
Target:	linus/x86_64-defconfig/x86_64-gcc8
Branch:	linus
Compiler:	x86_64-gcc8 (x86_64-linux-gcc (GCC) 8.5.0 / GNU ld (GNU Binutils) 2.36.1)
Config:	defconfig (download)
Log:	Download original No warnings found in log. Full Log # git rev-parse -q --verify 4356e9f841f7fbb945521cef3577ba394c65f3fc^{commit} 4356e9f841f7fbb945521cef3577ba394c65f3fc already have revision, skipping fetch # git checkout -q -f -B kisskb 4356e9f841f7fbb945521cef3577ba394c65f3fc # git clean -qxdf # < git log -1 # commit 4356e9f841f7fbb945521cef3577ba394c65f3fc # Author: Linus Torvalds <torvalds@linux-foundation.org> # Date: Fri Feb 9 12:39:31 2024 -0800 # # work around gcc bugs with 'asm goto' with outputs # # We've had issues with gcc and 'asm goto' before, and we created a # 'asm_volatile_goto()' macro for that in the past: see commits # 3f0116c3238a ("compiler/gcc4: Add quirk for 'asm goto' miscompilation # bug") and a9f180345f53 ("compiler/gcc4: Make quirk for # asm_volatile_goto() unconditional"). # # Then, much later, we ended up removing the workaround in commit # 43c249ea0b1e ("compiler-gcc.h: remove ancient workaround for gcc PR # 58670") because we no longer supported building the kernel with the # affected gcc versions, but we left the macro uses around. # # Now, Sean Christopherson reports a new version of a very similar # problem, which is fixed by re-applying that ancient workaround. But the # problem in question is limited to only the 'asm goto with outputs' # cases, so instead of re-introducing the old workaround as-is, let's # rename and limit the workaround to just that much less common case. # # It looks like there are at least two separate issues that all hit in # this area: # # (a) some versions of gcc don't mark the asm goto as 'volatile' when it # has outputs: # # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420 # # which is easy to work around by just adding the 'volatile' by hand. # # (b) Internal compiler errors: # # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422 # # which are worked around by adding the extra empty 'asm' as a # barrier, as in the original workaround. # # but the problem Sean sees may be a third thing since it involves bad # code generation (not an ICE) even with the manually added 'volatile'. # # but the same old workaround works for this case, even if this feels a # bit like voodoo programming and may only be hiding the issue. # # Reported-and-tested-by: Sean Christopherson <seanjc@google.com> # Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/ # Cc: Nick Desaulniers <ndesaulniers@google.com> # Cc: Uros Bizjak <ubizjak@gmail.com> # Cc: Jakub Jelinek <jakub@redhat.com> # Cc: Andrew Pinski <quic_apinski@quicinc.com> # Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> # < /opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux-ld --version # < git log --format=%s --max-count=1 4356e9f841f7fbb945521cef3577ba394c65f3fc # make -s -j 40 ARCH=x86 O=/kisskb/build/linus_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux- x86_64_defconfig # < make -s -j 40 ARCH=x86 O=/kisskb/build/linus_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux- help # make -s -j 40 ARCH=x86 O=/kisskb/build/linus_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux- olddefconfig # make -s -j 40 ARCH=x86 O=/kisskb/build/linus_x86_64_defconfig_x86_64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.5.0-nolibc/x86_64-linux/bin/x86_64-linux- Completed OK # rm -rf /kisskb/build/linus_x86_64_defconfig_x86_64-gcc8 # Build took: 0:01:33.166013

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