Messages in this thread | | | Date | Thu, 27 Sep 2012 16:39:20 -0400 | From | Theodore Ts'o <> | Subject | Re: [PATCH next/mmotm] ext4: fix cache_es after merge_left |
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On Thu, Sep 27, 2012 at 01:31:28PM -0700, Hugh Dickins wrote: > Kernel build with CONFIG_DEBUG_SLAB or CONFIG_SLUB_DEBUG slub_debug=FPZ > gives me kernel BUG at fs/ext4/extents_status.c:142! That's the > BUG_ON(es->start + es->len < es->start) in extent_status_end() called > from ext4_es_insert_extent(). tree->cache_es has been freed and poisoned. > > This comes from when ext4_es_try_to_merge_left() merges es into leftward > es1, but ext4_es_insert_extent()'s out then updates cache_es to the freed > extent_status. ext4_es_try_to_merge_right() does not pose a problem. > > Change ext4_es_try_to_merge_left() to return whichever extent_status > should be recorded in tree->cache_es. Remove cache_es update from > both of them, leaving that to ext4_es_insert_extent()'s out label. > > Signed-off-by: Hugh Dickins <hughd@google.com>
Hugh, thanks for finding this bug!
Zheng, you were going to send me an updated patch series; can you take care of merging this patch into your patch series (and crediting Hugh with a Signed-off-by as appropriate)?
Thanks!!
- Ted
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