lkml.org 
[lkml]   [2007]   [Feb]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: [RFC][PATCH 3/3] Freezer: Prevent ___call_usermodehelper from missing freezing requests
    Date
    On Monday, 26 February 2007 12:58, Aneesh Kumar wrote:
    > On 2/26/07, Rafael J. Wysocki <rjw@sisk.pl> wrote:
    > > NOTE: Alternatively, we can just drop flush_signals() from there, but I'm not
    > > sure that's the right thing to do.
    > >
    > > ---
    > > From: Rafael J. Wysocki <rjw@sisk.pl>
    > >
    > > Since ____call_usermodehelper() calls flush_signals(current), the task that
    > > enters it may miss a freezing request. However, if ____call_usermodehelper()
    > > clears TIF_FREEZE for the current task after flush_signals(current) returns, the
    > > freezer will generate one more freezing request for this task.
    > >
    > > Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
    > > ---
    > > kernel/kmod.c | 2 ++
    > > 1 file changed, 2 insertions(+)
    > >
    > > Index: linux-2.6.20-mm2/kernel/kmod.c
    > > ===================================================================
    > > --- linux-2.6.20-mm2.orig/kernel/kmod.c 2007-02-25 12:07:15.000000000 +0100
    > > +++ linux-2.6.20-mm2/kernel/kmod.c 2007-02-25 12:49:16.000000000 +0100
    > > @@ -34,6 +34,7 @@
    > > #include <linux/kernel.h>
    > > #include <linux/init.h>
    > > #include <linux/resource.h>
    > > +#include <linux/freezer.h>
    > > #include <asm/uaccess.h>
    > >
    > > extern int delete_module(const char *name, unsigned int flags);
    > > @@ -258,6 +259,7 @@ static int ____call_usermodehelper(void
    > > new_session = key_get(sub_info->ring);
    > > flush_signals(current);
    > > spin_lock_irq(&current->sighand->siglock);
    > > + do_not_freeze(current);
    > > old_session = __install_session_keyring(current, new_session);
    > > flush_signal_handlers(current, 1);
    > > sigemptyset(&current->blocked);
    > >
    >
    >
    > this need a comment . Otherwise one reading will read it as we don't
    > want it to freeze.
    >
    > How about
    > /*
    > clears TIF_FREEZE for the current task after flush_signals(current)
    > returns, so that the
    > freezer will generate one more freezing request for this task.
    >
    > */

    Looks reasonable, but Oleg wants to drop the flush_signals(current) ...

    Rafael
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-02-26 19:31    [W:0.026 / U:0.396 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site