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    SubjectRe: [PATCH 00/22] x86, objtool: several fixes/improvements
    On Sun, Jul 14, 2019 at 07:36:55PM -0500, Josh Poimboeuf wrote:
    > There have been a lot of objtool bug reports lately, mainly related to
    > Clang and BPF. As part of fixing those bugs, I added some improvements
    > to objtool which uncovered yet more bugs (some kernel, some objtool).
    >
    > I've given these patches a lot of testing with both GCC and Clang. More
    > compile testing of objtool would be appreciated, as the kbuild test
    > robot doesn't seem to be paying much attention to my branches lately.
    >
    > There are still at least three outstanding issues:
    >
    > 1) With clang I see:
    >
    > drivers/gpu/drm/i915/gem/i915_gem_execbuffer.o: warning: objtool: .altinstr_replacement+0x88: redundant UACCESS disable
    >
    > I haven't dug into it yet.
    >
    > 2) There's also an issue in clang where a large switch table had a bunch
    > of unused (bad) entries. It's not a code correctness issue, but
    > hopefully it can get fixed in clang anyway. See patch 20/22 for more
    > details.
    >
    > 3) CONFIG_LIVEPATCH is causing some objtool "unreachable instruction"
    > warnings due to the new -flive-patching flag. I have some fixes
    > pending, but this patch set is already long enough.
    >
    >
    > Jann Horn (1):
    > objtool: Support repeated uses of the same C jump table
    >
    > Josh Poimboeuf (21):
    > x86/paravirt: Fix callee-saved function ELF sizes
    > x86/kvm: Fix fastop function ELF metadata
    > x86/kvm: Fix frame pointer usage in vmx_vmenter()
    > x86/kvm: Don't call kvm_spurious_fault() from .fixup
    > x86/entry: Fix thunk function ELF sizes
    > x86/head/64: Annotate start_cpu0() as non-callable
    > x86/uaccess: Remove ELF function annotation from
    > copy_user_handle_tail()
    > x86/uaccess: Don't leak AC flag into fentry from mcsafe_handle_tail()
    > x86/uaccess: Remove redundant CLACs in getuser/putuser error paths
    > bpf: Disable GCC -fgcse optimization for ___bpf_prog_run()
    > objtool: Add mcsafe_handle_tail() to the uaccess safe list
    > objtool: Track original function across branches
    > objtool: Refactor function alias logic
    > objtool: Warn on zero-length functions
    > objtool: Change dead_end_function() to return boolean
    > objtool: Do frame pointer check before dead end check
    > objtool: Refactor sibling call detection logic
    > objtool: Refactor jump table code
    > objtool: Fix seg fault on bad switch table entry
    > objtool: convert insn type to enum
    > objtool: Support conditional retpolines

    Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

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