CONFIG_UBSAN_DIV_ZERO causes objtool: foo() falls through to the next function bar() #1657
Labels
[ARCH] x86_64
This bug impacts ARCH=x86_64
[CONFIG] allmodconfig
Issue affects allmodconfig on certain architectures
Reported upstream
This bug was filed on LLVM’s issue tracker, Phabricator, or the kernel mailing list.
[TOOL] objtool
warning is produced by the kernel's objtool
[WORKAROUND] Applied
This bug has an applied workaround
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nickdesaulniers
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[ARCH] x86_64
nickdesaulniers
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the
Reported upstream
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These appear to only be visible with With
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There are a lot more warnings of this nature after llvm/llvm-project@10c531c. At the parent commit: At that change: I suspect this is the same problem but I'll see which specific configurations trigger this and open a new issue if necessary. |
Yeah let's bisect the configs. Unless there's a bug in the LLVM patch, I have a sinking feeling that this is again sanitizer related. |
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This appears to be entirely related to With before the change: after that change: The
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nickdesaulniers
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
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submitted a patch to disable this config for now: https://lore.kernel.org/llvm/20220714205646.4023495-1-ndesaulniers@google.com/ |
nickdesaulniers
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[PATCH] Submitted
torvalds
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Linus picked up https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e5d523f1ae8f2cef01f8e071aeee432654166708. Let's keep this open so that we can work towards getting the config option re-enabled. |
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[WORKAROUND] Applied
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Change-Id: I9e9a142b2e332a210a757a30e732e09f0febddbc Signed-off-by: Alexander Winkowski <dereference23@outlook.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Change-Id: I9e9a142b2e332a210a757a30e732e09f0febddbc Signed-off-by: Alexander Winkowski <dereference23@outlook.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I98dd1aee705b3c1ebca270ce641b328ef150bdf4 Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I98dd1aee705b3c1ebca270ce641b328ef150bdf4 Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I98dd1aee705b3c1ebca270ce641b328ef150bdf4 Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: Ia4bd02e2340f830b5027a3871a94f06d6c0dcfa2 Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: Ia4bd02e2340f830b5027a3871a94f06d6c0dcfa2 Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: Iac6fed9ff2f7aab48bb559a5586910db31b5a9e9 Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: Iac6fed9ff2f7aab48bb559a5586910db31b5a9e9 Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: Iac6fed9ff2f7aab48bb559a5586910db31b5a9e9 Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: Iac6fed9ff2f7aab48bb559a5586910db31b5a9e9 Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: Iac6fed9ff2f7aab48bb559a5586910db31b5a9e9 Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: Ic42632f882281fd379df1638edf3a5ac0ebb5570 Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I1f3177aa1bf13dec27fa9af165debfbeab1972e2 Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: If70d1bbafe037f6f7d92de37eb3596d73e96aabb Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I28db1f1fe9da8787264431a191e5fc6e4b7f2ddb Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I28db1f1fe9da8787264431a191e5fc6e4b7f2ddb Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Aug 11, 2024
Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I28db1f1fe9da8787264431a191e5fc6e4b7f2ddb Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Aug 13, 2024
Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I28db1f1fe9da8787264431a191e5fc6e4b7f2ddb Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Aug 14, 2024
Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I28db1f1fe9da8787264431a191e5fc6e4b7f2ddb Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I28db1f1fe9da8787264431a191e5fc6e4b7f2ddb Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: Ib148a383852bd6a0e9e2c8bafcd10961c37991dc Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Sep 6, 2024
Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: Ib148a383852bd6a0e9e2c8bafcd10961c37991dc Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: Ib148a383852bd6a0e9e2c8bafcd10961c37991dc Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: Ib148a383852bd6a0e9e2c8bafcd10961c37991dc Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Sep 24, 2024
Building with UBSAN_DIV_ZERO with clang produces numerous fallthrough warnings from objtool. In the case of uncheck division, UBSAN_DIV_ZERO may introduce new control flow to check for division by zero. Because the result of the division is undefined, LLVM may optimize the control flow such that after the call to __ubsan_handle_divrem_overflow doesn't matter. If panic_on_warn was set, __ubsan_handle_divrem_overflow would panic. The problem is is that panic_on_warn is run time configurable. If it's disabled, then we cannot guarantee that we will be able to recover safely. Disable this config for clang until we can come up with a solution in LLVM. Link: ClangBuiltLinux/linux#1657 Link: llvm/llvm-project#56289 Link: https://lore.kernel.org/lkml/CAHk-=wj1qhf7y3VNACEexyp5EbkNpdcu_542k-xZpzmYLOjiCg@mail.gmail.com/ Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: Ib148a383852bd6a0e9e2c8bafcd10961c37991dc Acked-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Alexander Winkowski <dereference23@outlook.com> (cherry picked from commit 65b37d8468a4afffbef4ba91c5ae53d3d90e7911) Signed-off-by: TogoFire <togofire@mailfence.com>
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Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>It seems like a bunch of these have something to do with
__ubsan_handle_divrem_overflow. It's not clear to me yet that clang expects that fn to benoreturn(I haven't found anything in the IR or clang sources that assumes so), as hypothesized here.The text was updated successfully, but these errors were encountered: