Re: [PATCH v2] mm: hwpoison: coredump: support recovery from dump_user_range()

[Kefeng Wang]

On 2023/4/28 0:45, Luck, Tony wrote:
> > > But in the core dump case there is no return to user. The process is being
> > > terminated by the signal that leads to this core dump. So even though you
> > > may consider the page being accessed to be a "user" page, you can't fix
> > > it by queueing work to run on return to user.
> >
> > For coredump，the task work will be called too, see following code,
> >
> > get_signal
> > 	sig_kernel_coredump
> > 		elf_core_dump
> > 			dump_user_range
> > 				_copy_from_iter // with MC-safe copy, return without panic
> > 	do_group_exit(ksig->info.si_signo);
> > 		do_exit
> > 			exit_task_work
> > 				task_work_run
> > 					kill_me_never
> > 						memory_failure
>
> Nice. I didn't realize that the exit code path would clear any pending task_work() requests.
> But it makes sense that this happens. Thanks for filling a gap in my knowledge.
Yep, we could be benefit from it to unify memory failure handling :)

> -Tony