lkml.org 
[lkml]   [2008]   [May]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: ACPI: kmemcheck: Caught 16-bit read from freed memory (f7c12ec6)
    Hello,

    On Thu, May 8, 2008 at 7:35 AM, Lin Ming <ming.m.lin@intel.com> wrote:
    > Here comes a simple patch that fixes the warning in my machine.
    >
    > Vegard, would you please help to test it in your machine?
    >

    Thanks for the try, but unfortunately this does not solve the problem.

    Please note that kmemcheck is an patch to the kernel; without it you
    will never see the warning. You can pull it from
    git://git.kernel.org/pub/scm/linux/kernel/git/vegard/kmemcheck.git current
    though it is unlikely that it will help you more than looking at the
    code (or the report) will do.

    > Thanks,
    > Lin Ming
    >
    > Signed-off-by: Lin Ming <ming.m.lin@intel.com>
    > ---
    > diff --git a/drivers/acpi/parser/psargs.c b/drivers/acpi/parser/psargs.c
    > index f1e8bf6..ef55d24 100644
    > --- a/drivers/acpi/parser/psargs.c
    > +++ b/drivers/acpi/parser/psargs.c
    > @@ -268,7 +268,7 @@ acpi_ps_get_next_namepath(struct acpi_walk_state
    > *walk_state,

    > */
    > if (ACPI_SUCCESS(status) &&
    > possible_method_call && (node->type == ACPI_TYPE_METHOD)) {
    > - if (walk_state->op->common.aml_opcode == AML_UNLOAD_OP) {
    > + if (walk_state->op && walk_state->op->common.aml_opcode ==
    > AML_UNLOAD_OP) {
    > /*
    > * acpi_ps_get_next_namestring has increased the AML pointer,
    > * so we need to restore the saved AML pointer for method call.

    Also, noticing your change, I can see why it makes no difference:
    Pekka already found that it is walk_state->op that has the value of
    0xf7c12ec6 (e.g. the pointer being dereferenced), so the test will
    still succeed.

    On the other hand, I have discovered what seems to be a deficiency in
    kmemcheck (i.e. it might be my fault entirely), so it is possible that
    the warning is bogus. Will send an update shortly.


    Vegard

    --
    "The animistic metaphor of the bug that maliciously sneaked in while
    the programmer was not looking is intellectually dishonest as it
    disguises that the error is the programmer's own creation."
    -- E. W. Dijkstra, EWD1036


    \
     
     \ /
      Last update: 2008-05-08 08:09    [W:0.023 / U:2.956 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site