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    Subject[PATCH 5.13 348/800] objtool: Dont make .altinstructions writable
    Date
    From: Josh Poimboeuf <jpoimboe@redhat.com>

    [ Upstream commit e31694e0a7a709293319475d8001e05e31f2178c ]

    When objtool creates the .altinstructions section, it sets the SHF_WRITE
    flag to make the section writable -- unless the section had already been
    previously created by the kernel. The mismatch between kernel-created
    and objtool-created section flags can cause failures with external
    tooling (kpatch-build). And the section doesn't need to be writable
    anyway.

    Make the section flags consistent with the kernel's.

    Fixes: 9bc0bb50727c ("objtool/x86: Rewrite retpoline thunk calls")
    Reported-by: Joe Lawrence <joe.lawrence@redhat.com>
    Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
    Signed-off-by: Ingo Molnar <mingo@kernel.org>
    Link: https://lore.kernel.org/r/6c284ae89717889ea136f9f0064d914cd8329d31.1624462939.git.jpoimboe@redhat.com
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    tools/objtool/arch/x86/decode.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
    index 523aa4157f80..bc821056aba9 100644
    --- a/tools/objtool/arch/x86/decode.c
    +++ b/tools/objtool/arch/x86/decode.c
    @@ -684,7 +684,7 @@ static int elf_add_alternative(struct elf *elf,
    sec = find_section_by_name(elf, ".altinstructions");
    if (!sec) {
    sec = elf_create_section(elf, ".altinstructions",
    - SHF_WRITE, size, 0);
    + SHF_ALLOC, size, 0);

    if (!sec) {
    WARN_ELF("elf_create_section");
    --
    2.30.2


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