Messages in this thread | | | From | Linus Torvalds <> | Date | Mon, 18 Apr 2011 13:27:10 -0700 | Subject | Re: 2.6.39-rc1 nouveau(?) regression (bisected) |
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On Mon, Apr 18, 2011 at 1:02 PM, Marcin Slusarz <marcin.slusarz@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.
Linus -- 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/
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