On Thu, May 17, 2018 at 05:01:45PM +0800, ethanwu wrote:
commit 998ac6d21cfd6efd58f5edf420bae8839dda9f2a upstream
In preivous patch: Btrfs: kill trans in run_delalloc_nocow and btrfs_cross_ref_exist We avoid starting btrfs transaction and get this information from fs_info->running_transaction directly.
When accessing running_transaction in check_delayed_ref, there's a chance that current transaction will be freed by commit transaction after the NULL pointer check of running_transaction is passed.
After looking all the other places using fs_info->running_transaction, they are either protected by trans_lock or holding the transactions.
Fix this by using trans_lock and increasing the use_count.
Fixes: e4c3b2dcd144 ("Btrfs: kill trans in run_delalloc_nocow and btrfs_cross_ref_exist") CC: stable@vger.kernel.org # 4.14+ Signed-off-by: ethanwu ethanwu@synology.com Signed-off-by: David Sterba dsterba@suse.com
fs/btrfs/extent-tree.c | 7 +++++++ 1 file changed, 7 insertions(+)
Thanks for the backport, now queued up.
greg k-h