On Wed, Aug 14, 2019 at 06:09:17PM +0200, Oleg Nesterov wrote: > On 08/14, Christian Brauner wrote: > > > > and a signal could come in between the system call that > > retrieved the process gorup and the call to waitid that changes the > ^^^^^ > > current process group. > > I noticed this typo only because I spent 2 minutes or more trying to > understand this sentence ;) But yes, a signal handler or another thread > can change pgrp in between. > > Reviewed-by: Oleg Nesterov <o...@redhat.com>
Applied-to: https://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git/log/?h=pidfd on top of P_PIDFD changes (cf. [1]) with merge conflict resolved (cf. [2]). (All changes on top of v5.3-rc1.) Merged-into: https://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git/log/?h=for-next and should show up in linux-next tomorrow. Thanks! Christian /* References */ [1]: https://lore.kernel.org/r/20190727222229.6516-2-christ...@brauner.io [2]: patch after resolved merge-conflict: kernel/exit.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/exit.c b/kernel/exit.c index 64bb6893a37d..d2d74a7b81d1 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1596,10 +1596,13 @@ static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop, break; case P_PGID: type = PIDTYPE_PGID; - if (upid <= 0) + if (upid < 0) return -EINVAL; - pid = find_get_pid(upid); + if (upid) + pid = find_get_pid(upid); + else + pid = get_task_pid(current, PIDTYPE_PGID); break; case P_PIDFD: type = PIDTYPE_PID;
