On Tue, Dec 19, 2006 at 12:39:46AM +0100, Haar János wrote: > From: "David Chinner" <[EMAIL PROTECTED]> > > On Mon, Dec 18, 2006 at 09:17:50AM +0100, Haar János wrote: > > > From: "David Chinner" <[EMAIL PROTECTED]> > > > > Ok, I've never heard of a problem like this before and you are doing > > > > something that very few ppl are doing (i.e. XFS on NBD). I'd start > > > > Hence I'd start by suspecting a bug in the NBD driver. > > > > > > Ok, if you have right, this also can be in context with the following > issue: > > > > > > http://download.netcenter.hu/bughunt/20061217/messages.txt (10KB) > > > > Which appears to be a crash in wake_up_process() when doing memory > > reclaim (waking the xfsbufd). > > Sorry, can you translate it to "poor mans language"? :-) > This is a different bug?
Don't know - it's a different crash, but once again one that I've never heard of occurring before. > > Ok, I've found this pattern: > > > > #define POISON_FREE 0x6b > > > > Can you confirm that you are running with CONFIG_DEBUG_SLAB=y? > > Yes, i build with this option enabled. > Is this wrong? No, but it does slow your machine down. > > If so, we have a use after free occurring here and it would also > > explain why no-one has reported it before. > > > > FWIW, can you turn on CONFIG_XFS_DEBUG=y and see if that triggers > > a different bug check prior to the above dump? > > [EMAIL PROTECTED] linux-2.6.19]# make bzImage > scripts/kconfig/conf -s arch/x86_64/Kconfig > .config:7:warning: trying to assign nonexistent symbol XFS_DEBUG > > I have missed something? No - I forgot that config option doesn't exist in mainline XFS - it's only in the dev tree. FWIW, I've run XFSQA twice now on a scsi disk with slab debuggin turned on and I haven't seen this problem. I'm not sure how to track down the source of the problem without a test case, but as a quick test, can you try the following patch? Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group --- fs/xfs/linux-2.6/xfs_buf.c | 4 ++++ 1 file changed, 4 insertions(+) Index: 2.6.x-xfs-new/fs/xfs/linux-2.6/xfs_buf.c =================================================================== --- 2.6.x-xfs-new.orig/fs/xfs/linux-2.6/xfs_buf.c 2006-12-19 12:22:54.000000000 +1100 +++ 2.6.x-xfs-new/fs/xfs/linux-2.6/xfs_buf.c 2006-12-19 13:48:36.937118569 +1100 @@ -942,11 +942,14 @@ xfs_buf_unlock( /* * Pinning Buffer Storage in Memory * Ensure that no attempt to force a buffer to disk will succeed. + * Hold the buffer so we don't attempt to free it while it + * is pinned. */ void xfs_buf_pin( xfs_buf_t *bp) { + xfs_buf_hold(bp); atomic_inc(&bp->b_pin_count); XB_TRACE(bp, "pin", (long)bp->b_pin_count.counter); } @@ -958,6 +961,7 @@ xfs_buf_unpin( if (atomic_dec_and_test(&bp->b_pin_count)) wake_up_all(&bp->b_waiters); XB_TRACE(bp, "unpin", (long)bp->b_pin_count.counter); + xfs_buf_rele(bp); } int - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/