On Tue, Apr 19, 2011 at 11:47:47PM +0200, Marcin Slusarz wrote:
> On Mon, Apr 18, 2011 at 01:27:10PM -0700, Linus Torvalds wrote:
> > On Mon, Apr 18, 2011 at 1:02 PM, Marcin Slusarz
> > <marcin.slusarz at gmail.com> wrote:
> > >
> > > It's some nasty corruption:
> >
> > Looks like something wrote 0xffffffff to free'd memory.
> >
> > Enabling DEBUG_PAGEALLOC *might* show where it happens.
> >
> > >
> > > [ ? ?6.523867]
> > > =============================================================================
> > > [ ? ?6.523916] BUG sysfs_dir_cache: Poison overwritten
> > > [ ? ?6.523949]
> > > -----------------------------------------------------------------------------
> > > [ ? ?6.523950]
> > > [ ? ?6.524016] INFO: 0xffff8801bb47df4c-0xffff8801bb47df4f. First byte
> > > 0xff instead of 0x6b
> > > [ ? ?6.524061] INFO: Slab 0xffffea00060f7b58 objects=22 used=21
> > > fp=0xffff8801bb47df18 flags=0x80000000000000c1
> > > [ ? ?6.524110] INFO: Object 0xffff8801bb47df18 @offset=3864 fp=0x ? ? ? ?
> > > ?(null)
> > > [ ? ?6.524111]
> > > [ ? ?6.524170] Bytes b4 0xffff8801bb47df08: ?00 00 00 00 00 00 00 00 5a
> > > 5a 5a 5a 5a 5a 5a 5a ........ZZZZZZZZ
> > > [ ? ?6.524516] ? Object 0xffff8801bb47df18: ?6b 6b 6b 6b 6b 6b 6b 6b 6b
> > > 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> > > [ ? ?6.524862] ? Object 0xffff8801bb47df28: ?6b 6b 6b 6b 6b 6b 6b 6b 6b
> > > 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> > > [ ? ?6.525208] ? Object 0xffff8801bb47df38: ?6b 6b 6b 6b 6b 6b 6b 6b 6b
> > > 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
> > > [ ? ?6.525556] ? Object 0xffff8801bb47df48: ?6b 6b 6b 6b ff ff ff ff 6b
> > > 6b 6b 6b 6b 6b 6b 6b kkkk<FF><FF><FF><FF>kkkkkkkk
> >
> > So here the 0xffffffff is pretty obvious.
> >
> > > and in another boot:
> > >
> > > [ ? ?6.704786] BUG: unable to handle kernel paging request at
> > > ffffffffbc70b058
> >
> > Here it is less obvious, but it was _probably_ a regular kernel
> > pointer of the type 0xffff8801bc70b058 before the high bits were
> > overwritten by a 0xffffffff.
> >
> > So then sysfs_refresh_inode() follows that pointer, and crashes.
> >
> > Just a guess, obviously, but it looks rather likely.
>
> Thanks. It helped a bit.
> I'll send two patches in response to this message, one of which fixes this
> bug.
Thanks Marcin, now my system boots finely again. Consider this bug CLOSED
and FIXED. Thanks again,
Dominik
