On 2020/9/21 18:25, Jan Kara wrote:
On Sat 19-09-20 05:39:23, Shijie Luo wrote:
So 4.18 is rather old and we had several fixes in this area for crashes
similar to the one you show above. The list was likely:
68f23b89067 ("memcg: fix a crash in wb_workfn when a device disappears")
but there were multiple changes before that to bdi logic to fix lifetime
issues when devices are hot-removed.
Thanks for your reply, we checked several fixes in wb_workfn , and
finally found
this patch (ceff86fddae8 ext4: Avoid freeing inodes on dirty list) works.
Our fsstress process randomly uses ioctl interface to set inode with
journal data flag, ext4 inode with journal data
flags is possible to be marked dirty and added to writeback lists again.
When locked_inode_to_wb_and_lock_list in __mark_inode_dirty releases
inode->i_lock and do not lock
wb->list_lock, simultaneously the inode is evicted and removed from
writeback lists, it's possible this
inode will be added to writeback list again. This problem causes inode
allocated from slab is still on
writeback list, and may causes crash because destory_inode set inode->wb
to be NULL.
