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    Subject[PATCH 4.9 085/125] objtool: Fix switch table detection in .text.unlikely
    Date
    From: Josh Poimboeuf <jpoimboe@redhat.com>

    commit b401efc120a399dfda1f4d2858a4de365c9b08ef upstream.

    If a switch jump table's indirect branch is in a ".cold" subfunction in
    .text.unlikely, objtool doesn't detect it, and instead prints a false
    warning:

    drivers/media/v4l2-core/v4l2-ioctl.o: warning: objtool: v4l_print_format.cold()+0xd6: sibling call from callable instruction with modified stack frame
    drivers/hwmon/max6650.o: warning: objtool: max6650_probe.cold()+0xa5: sibling call from callable instruction with modified stack frame
    drivers/media/dvb-frontends/drxk_hard.o: warning: objtool: init_drxk.cold()+0x16f: sibling call from callable instruction with modified stack frame

    Fix it by comparing the function, instead of the section and offset.

    Fixes: 13810435b9a7 ("objtool: Support GCC 8's cold subfunctions")
    Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
    Signed-off-by: Borislav Petkov <bp@suse.de>
    Reviewed-by: Miroslav Benes <mbenes@suse.cz>
    Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    Link: https://lkml.kernel.org/r/157c35d42ca9b6354bbb1604fe9ad7d1153ccb21.1585761021.git.jpoimboe@redhat.com
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    tools/objtool/check.c | 5 +----
    1 file changed, 1 insertion(+), 4 deletions(-)

    --- a/tools/objtool/check.c
    +++ b/tools/objtool/check.c
    @@ -914,10 +914,7 @@ static struct rela *find_switch_table(st
    * it.
    */
    for (;
    - &insn->list != &file->insn_list &&
    - insn->sec == func->sec &&
    - insn->offset >= func->offset;
    -
    + &insn->list != &file->insn_list && insn->func && insn->func->pfunc == func;
    insn = insn->first_jump_src ?: list_prev_entry(insn, list)) {

    if (insn != orig_insn && insn->type == INSN_JUMP_DYNAMIC)

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