Messages in this thread | | | From | Neil Brown <> | Date | Mon, 13 Nov 2006 17:42:38 +1100 | Subject | Re: [Bugme-new] [Bug 7495] New: Kernel periodically hangs. |
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On Saturday November 11, akpm@osdl.org wrote: > On Sat, 11 Nov 2006 03:29:32 -0800 > bugme-daemon@bugzilla.kernel.org wrote: > > > http://bugzilla.kernel.org/show_bug.cgi?id=7495 > > > > Summary: Kernel periodically hangs. > > Kernel Version: Linux version 2.6.18.2 (root@pub) (gcc version 3.4.6) > > #13 SMP Fr > > Status: NEW > > Severity: blocking > > Owner: other_other@kernel-bugs.osdl.org > > Submitter: alex@hausnet.ru
So getting back to the main issue in this bug report.....
> > > > > > [42587.676000] BUG: unable to handle kernel NULL pointer dereference at > > virtual address 0000003c
it would appear that in: if (inode->i_sb && inode->i_sb->s_op->clear_inode) inode->i_sb->s_op->clear_inode(inode);
inode->i_sb->s_op is NULL. This is unfortunate :-) alloc_super initialises s_op to '&default_op' and it isn't cleared on unmount, so the implication seems to be that i_sb has been freed and the memory has been reused. This tends to suggest that generic_shutdown_super isn't releasing all inodes before the superblock gets destroyed.
I cannot see how this could be happening yet, but it might be helpful to compile with CONFIG_DEBUG_SLAB and maybe even CONFIG_DEBUG_PAGEALLOC. That might make the problem trigger earlier and so be easier to track.
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