On Fri 12-06-20 15:13:22, Naresh Kamboju wrote: > On Thu, 11 Jun 2020 at 15:25, Michal Hocko <mhocko@xxxxxxxxxx> wrote: > > > > On Fri 29-05-20 11:49:20, Michal Hocko wrote: > > > On Fri 29-05-20 02:56:44, Chris Down wrote: > > > > Yafang Shao writes: > > > Agreed. Even if e{low,min} might still have some rough edges I am > > > completely puzzled how we could end up oom if none of the protection > > > path triggers which the additional debugging should confirm. Maybe my > > > debugging patch is incomplete or used incorrectly (maybe it would be > > > esier to use printk rather than trace_printk?). > > > > It would be really great if we could move forward. While the fix (which > > has been dropped from mmotm) is not super urgent I would really like to > > understand how it could hit the observed behavior. Can we double check > > that the debugging patch really doesn't trigger (e.g. > > s@trace_printk@printk in the first step)? > > Please suggest to me the way to get more debug information > by providing kernel debug patches and extra kernel configs. > > I have applied your debug patch and tested on top on linux next 20200612 > but did not find any printk output while running mkfs -t ext4 /drive test case. Have you tried s@trace_printk@printk@ in the patch? AFAIK trace_printk doesn't dump anything into the printk ring buffer. You would have to look into trace ring buffer. -- Michal Hocko SUSE Labs