Re: [PATCH 1/1] tty: set_termios/set_termiox should not return -EINTR

[Oleg Nesterov <oleg@redhat.com>]

On 01/29, Jiri Slaby wrote:
>
> On 01/29/2013 08:07 PM, Oleg Nesterov wrote:
> >
> > Change set_termios/set_termiox to return -ERESTARTSYS to fix this
> > particular problem.
>
> This looks reasonable. However given the link above says:
>  You are not authorized to access bug #904907.
> the description above is poor. What problem exactly does this fix?

A syscall must never return EINTR unless it can not be restarted
(or it should not be restarted by, say, historical reasons).

In this case ioctl(TCSETAW) returns -EINTR even if it is interrupted
by the signal which has the SA_RESTART handler. This doesn't look right
no matter what.

> Why this should go to stable at all?

OK, this is up to you.

But if this patch is correct, perhaps it should be backported. This
-EINTR breaks /bin/bash which doesn't expect it, this leads to
"*** glibc detected *** ./bash-4.1.2-14.el6/bin/bash: double free or corruption (out):"

Perhaps /bin/bash is buggy too, I do not know. Probably Roman and
Lingzhu can tell more.

Oleg.