lkml.org 
[lkml]   [2007]   [Nov]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: 2.6.24-rc1-gb4f5550 oops
    On Mon, 12 Nov 2007 19:05:49 +0100
    Peter Zijlstra <peterz@infradead.org> wrote:

    >
    > On Thu, 2007-11-08 at 23:49 +0100, Rafael J. Wysocki wrote:
    > > On Thursday, 8 of November 2007, Grant Wilson wrote:
    > > > On Thu, 8 Nov 2007 22:42:21 +0100
    > > > "Rafael J. Wysocki" <rjw@sisk.pl> wrote:
    > > >
    > > > > On Thursday, 8 of November 2007, Grant Wilson wrote:
    > > > > > On Thu, 8 Nov 2007 16:53:10 +0100
    > > > > > "Rafael J. Wysocki" <rjw@sisk.pl> wrote:
    > > > > >
    > > > > > > On Thursday, 8 of November 2007, Grant Wilson wrote:
    > > > > > > > On Thu, 8 Nov 2007 01:06:21 +0100
    > > > > > > > "Rafael J. Wysocki" <rjw@sisk.pl> wrote:
    > > > > > > >
    > > > > > > > > On Monday, 5 of November 2007, Grant Wilson wrote:
    > > > > > > > > > Hi,
    > > > > > > > > > I got this oops on 2.6.24-rc1-641-gb4f5550:
    > > > > > > > >
    > > > > > > > > (1) Is this reproducible?
    > > > > > > > > (2) Did it happen previously on your system?
    > > > > > > > >
    > > > > > > > > [18073.371126] Unable to handle kernel NULL pointer dereference at 0000000000000120 RIP:
    > > > > > > > > [18073.371134] [<ffffffff8023572e>] check_preempt_wakeup+0x6e/0x110
    > > > > > > >
    > > > > > > > This has now happened twice - the second time was last night when
    > > > > > > > running 2.6.24-rc2.
    > > > > > > >
    > > > > > > > Here's that second occurrence:
    > > > > > > >
    > > > > > [snip]
    > > > > > >
    > > > > > > Hmm.
    > > > > > >
    > > > > > > Please run "gdb vmlinux" and see what code corresponds to
    > > > > > > check_preempt_wakeup+0x6e in your kernel.
    > > > > >
    > > > > >
    > > > > > Dump of assembler code for function check_preempt_wakeup:
    > > > >
    > > > > Well, thanks, but I meant the source code. Please do "gdb vmlinux" and then
    > > > > "l *check_preempt_wakeup+0x6e" in gdb.
    > > >
    > > > Here's the requested output:
    > > >
    > > > (gdb) l *check_preempt_wakeup+0x6e
    > > > 0xffffffff802329ae is in check_preempt_wakeup (kernel/sched_fair.c:668).
    > > > 663
    > > > 664 /* Do the two (enqueued) entities belong to the same group ? */
    > > > 665 static inline int
    > > > 666 is_same_group(struct sched_entity *se, struct sched_entity *pse)
    > > > 667 {
    > > > 668 if (se->cfs_rq == pse->cfs_rq)
    > > > 669 return 1;
    > > > 670
    > > > 671 return 0;
    > > > 672 }
    > >
    > > Well, it looks like either se or pse is NULL.
    > >
    > > Ingo, can you please have a look?
    >
    > Most puzzling this, it should be guaranteed that the top sched_entities
    > are of the same group, therefore avoiding this loop into NULL. Obviously
    > something has gone wrong.
    >
    > Grant, is there anything specific you can tell us about how to reproduce
    > this?

    I'm afraid not. It has only happened twice and both times I was away
    from the box in question at the time of failure, so it wasn't doing a
    great deal.

    I'm running 2.6.24-rc2 on two boxes and both times it happened on the
    box running a quad core processor.

    Grant

    -
    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: 2007-11-12 19:33    [W:4.341 / U:0.016 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site