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    Subject[PATCH 3.10 12/23] ftrace/x86: Load ftrace_ops in parameter not the variable holding it
    Date
    3.10-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Steven Rostedt <rostedt@goodmis.org>

    commit 1739f09e33d8f66bf48ddbc3eca615574da6c4f6 upstream.

    Function tracing callbacks expect to have the ftrace_ops that registered it
    passed to them, not the address of the variable that holds the ftrace_ops
    that registered it.

    Use a mov instead of a lea to store the ftrace_ops into the parameter
    of the function tracing callback.

    Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
    Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
    Link: http://lkml.kernel.org/r/20131113152004.459787f9@gandalf.local.home
    Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    arch/x86/kernel/entry_32.S | 4 ++--
    arch/x86/kernel/entry_64.S | 2 +-
    2 files changed, 3 insertions(+), 3 deletions(-)

    --- a/arch/x86/kernel/entry_32.S
    +++ b/arch/x86/kernel/entry_32.S
    @@ -1075,7 +1075,7 @@ ENTRY(ftrace_caller)
    pushl $0 /* Pass NULL as regs pointer */
    movl 4*4(%esp), %eax
    movl 0x4(%ebp), %edx
    - leal function_trace_op, %ecx
    + movl function_trace_op, %ecx
    subl $MCOUNT_INSN_SIZE, %eax

    .globl ftrace_call
    @@ -1133,7 +1133,7 @@ ENTRY(ftrace_regs_caller)
    movl 12*4(%esp), %eax /* Load ip (1st parameter) */
    subl $MCOUNT_INSN_SIZE, %eax /* Adjust ip */
    movl 0x4(%ebp), %edx /* Load parent ip (2nd parameter) */
    - leal function_trace_op, %ecx /* Save ftrace_pos in 3rd parameter */
    + movl function_trace_op, %ecx /* Save ftrace_pos in 3rd parameter */
    pushl %esp /* Save pt_regs as 4th parameter */

    GLOBAL(ftrace_regs_call)
    --- a/arch/x86/kernel/entry_64.S
    +++ b/arch/x86/kernel/entry_64.S
    @@ -88,7 +88,7 @@ END(function_hook)
    MCOUNT_SAVE_FRAME \skip

    /* Load the ftrace_ops into the 3rd parameter */
    - leaq function_trace_op, %rdx
    + movq function_trace_op(%rip), %rdx

    /* Load ip into the first parameter */
    movq RIP(%rsp), %rdi



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