On Wed 07-11-18 15:48:20, Daniel Colascione wrote:

On Tue, Nov 6, 2018 at 1:05 PM, Michal Hocko [off-list ref] wrote:

quoted

On Mon 05-11-18 13:22:05, Daniel Colascione wrote:

quoted

State explicitly that holding a /proc/pid file descriptor open does
not reserve the PID. Also note that in the event of PID reuse, these
open file descriptors refer to the old, now-dead process, and not the
new one that happens to be named the same numeric PID.

This sounds quite obvious

Many people *on* *LKML* were wrong about this behavior. If it's not
obvious to experienced kernel developers, it's certainly not obvious
to the public.

Fair enough

quoted

otherwise anybody could simply DoS the system
by consuming all available pids.

People can do that today using the instrument of terror widely known
as fork(2). The only thing standing between fork(2) and a full process
table is RLIMIT_NPROC.

not really. If you really do care about pid space depletion then you
should use pid cgroup controller.
-- 
Michal Hocko
SUSE Labs