On Thu, Jul 22, 2021 at 04:57:57PM +0800, Zhouyi Zhou wrote: > Thanks for reviewing, > > What I have deduced from the dmesg is: > In function do_swap_page, > after invoking > 3385 si = get_swap_device(entry); /* rcu_read_lock */ > and before > 3561 out: > 3562 if (si) > 3563 put_swap_device(si); > The thread got scheduled out in > 3454 locked = lock_page_or_retry(page, vma->vm_mm, vmf->flags); > > I am only familiar with Linux RCU subsystem, hope mm people can solve our > confusions. I don't understamd why you're still talking. The problem is understood. You need to revert the unnecessary backport of 2799e77529c2 and 2efa33fc7f6e
