Re: kernel BUG at mm/rmap.c:480 in 2.6.10-rc3-bk7

From: Nick Piggin (nickpiggin_at_yahoo.com.au)
Date: 12/15/04

  • Next message: Werner Almesberger: "Re: [RFC] Splitting kernel headers and deprecating __KERNEL__" 
    To: Hugh Dickins <hugh@veritas.com>
Date:	Wed, 15 Dec 2004 11:10:10 +1100

    On Tue, 2004-12-14 at 23:26 +0000, Hugh Dickins wrote:
    > On Tue, 14 Dec 2004, Greg KH wrote:
    > >
    > > So I finally try to get dri working on my laptop and I get the following
    > > kernel bug when killing X (the program gish was running at the time):
    > >
    > > kernel BUG at mm/rmap.c:480!
    > > EIP is at page_remove_rmap+0x32/0x40
    > > Process gish (pid: 10864, threadinfo=c8aea000 task=c7c2c040)
    > > [<c0141495>] zap_pte_range+0x135/0x290
    > >...
    > > [<c0145f41>] exit_mmap+0x71/0x140
    > > [<c01163c4>] mmput+0x24/0x80
    > > [<c011a756>] do_exit+0x146/0x370
    > >...
    >
    > It's my BUG_ON(page_mapcount(page) < 0).
    >
    > We've had about one report per month, over the last six months.
    > But this is the first citing "gish"; sometimes it's been "cc1".
    >
    > I've given it a lot of thought, but I'm still mystified. The last
    > report turned out to be attributable to bad memory; but this BUG_ON
    > is too persistent and specific to be put down to that in all cases.
    >
    > One case that's easy to explain: if it was preceded (perhaps hours
    > earlier) by a "Bad page state" message and stacktrace, referring to
    > the same page (in ecx, edx, ebp in your dump), which showed non-zero
    > mapcount, then this is an after-effect of bad_page resetting mapcount.
    > And the real problem was probably a double free, which bad_page noted,
    > but carried on regardless. Worth checking your logs for, let us know,
    > but there have been several reports where that's definitely not so.
    >

    "EIP: 0060:[<c0147d72>] Not tainted VLI"
                                  ^^^^^^^^^^^

    Just FYI, that kernel should be tainting on bad_page...

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  • Next message: Werner Almesberger: "Re: [RFC] Splitting kernel headers and deprecating __KERNEL__"