On Sat, Mar 07, 2020 at 12:00:07PM +0100, Christian Brauner wrote:
On Fri, Mar 06, 2020 at 11:23:14AM -0600, minyard@acm.org wrote:
From: Corey Minyard cminyard@mvista.com
Recent changes to alloc_pid() allow the pid number to be specified on the command line. If set_tid_size is set, then the code scanning the levels will hard-set retval to -EPERM, overriding it's previous -ENOMEM value.
After the code scanning the levels, there are error returns that do not set retval, assuming it is still set to -ENOMEM.
So set retval back to -ENOMEM after scanning the levels.
Fixes: 49cb2fc42ce4 "fork: extend clone3() to support setting a PID" Signed-off-by: Corey Minyard cminyard@mvista.com Cc: stable@vger.kernel.org # 5.5 Cc: Adrian Reber areber@redhat.com Cc: Christian Brauner christian.brauner@ubuntu.com Cc: Oleg Nesterov oleg@redhat.com Cc: Dmitry Safonov 0x7f454c46@gmail.com Cc: Andrei Vagin avagin@gmail.com
Thanks! I've pulled the patch now and applied.
I think that restores the old behavior. If you don't mind, I'll add a comment on top of it saying something like: "ENOMEM is not the most obvious choice but it's the what we've been exposing to userspace for a long time and it's also documented behavior. So we can't easily change it to something more sensible."
That's great. I was just looking through the code for another reason and noticed the issue. Every little thing counts for quality.
-corey
Acked-by: Christian Brauner christian.brauner@ubuntu.com