Messages in this thread | | | Date | Mon, 21 Aug 2017 22:05:20 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] pids: make task_tgid_nr_ns() safe |
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On Mon, Aug 21, 2017 at 05:35:02PM +0200, Oleg Nesterov wrote: > This was reported many times, and this was even mentioned in commit > 52ee2dfdd4f5 "pids: refactor vnr/nr_ns helpers to make them safe" but > somehow nobody bothered to fix the obvious problem: task_tgid_nr_ns() > is not safe because task->group_leader points to nowhere after the > exiting task passes exit_notify(), rcu_read_lock() can not help. > > We really need to change __unhash_process() to nullify group_leader, > parent, and real_parent, but this needs some cleanups. Until then we > can turn task_tgid_nr_ns() into another user of __task_pid_nr_ns() and > fix the problem. > > Reported-by: Troy Kensinger <tkensinger@google.com> > Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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