On Tue, 2011-04-19 at 23:47 +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. Nice catch. I'll push these to the nouveau tree now, and get them to Dave with some additional fixes.
Ben. > > Marcin >
