From: Dave Chinner Date: Mon, 12 Aug 2013 10:50:11 +0000 (+1000) Subject: xfs: use reference counts to free clean buffer items X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=2ad01f53dc34ef3180e555d40b331f95f269a0fa;p=linux-beck.git xfs: use reference counts to free clean buffer items When a transaction is cancelled and the buffer log item is clean in the transaction, the buffer log item is unconditionally freed. If the log item is in the AIL, however, this leads to a use after free condition as the item still has other users. In this case, xfs_buf_item_relse() should only be called on clean buffer items if the reference count has dropped to zero. This ensures only the last user frees the item. Signed-off-by: Dave Chinner Reviewed-by: Mark Tinguely Signed-off-by: Ben Myers --- diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c index 9358504e4b68..3a944b198e35 100644 --- a/fs/xfs/xfs_buf_item.c +++ b/fs/xfs/xfs_buf_item.c @@ -613,11 +613,9 @@ xfs_buf_item_unlock( } } } - if (clean) - xfs_buf_item_relse(bp); - else if (aborted) { + if (clean || aborted) { if (atomic_dec_and_test(&bip->bli_refcount)) { - ASSERT(XFS_FORCED_SHUTDOWN(lip->li_mountp)); + ASSERT(!aborted || XFS_FORCED_SHUTDOWN(lip->li_mountp)); xfs_buf_item_relse(bp); } } else