lkml.org 
[lkml]   [2010]   [Feb]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: PATCH? process_32.c:__switch_to() calls __math_state_restore() before updating current_task
    On 02/05, Oleg Nesterov wrote:
    >
    > In short: why restore_i387_xstate() does init_fpu() when !used_math(),
    > can't (or shouldn't) it merely do set_used_math() ?
    >
    > restore_i387_xstate:
    >
    > if (!used_math()) {
    > err = init_fpu(tsk);
    > if (err)
    > return err;
    > }
    >
    > note that buf != NULL. This means that used_math() was true when
    > get_sigframe() was called, otherwise buf == sigcontext->fpstate
    > would be NULL, right?
    >
    > So, the task must have the valid ->thread.xstate,

    This is probably correct. But a malicious user can set sc->fpsate
    and fool the kernel, so we must assume buf != NULL implies the
    valid ->xstate.

    Oleg.



    \
     
     \ /
      Last update: 2010-02-06 13:09    [W:0.020 / U:155.560 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site