On Mon, Jun 11, 2018 at 9:30 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Sun, Jun 10, 2018 at 11:47:56PM +0900, Tetsuo Handa wrote: > >> This looks quite strange that nobody is holding percpu_rw_semaphore for >> write but everybody is stuck trying to hold it for read. (Since there >> is no "X locks held by ..." line without followup "#0:" line, there is >> no possibility that somebody is in TASK_RUNNING state while holding >> percpu_rw_semaphore for write.) >> >> I feel that either API has a bug or API usage is wrong. >> Any idea for debugging this? > > Look at percpu_rwsem_release() and usage. The whole fs freezer thing is > magic. Do you mean that we froze fs? We tried to never-ever issue ioctl(FIFREEZE) during fuzzing. Are there other ways to do this?
