Messages in this thread | | | Date | Mon, 23 Nov 2015 18:05:52 -0500 | From | Tejun Heo <> | Subject | Re: [PATCH 1/2] ptrace: make wait_on_bit(JOBCTL_TRAPPING_BIT) in ptrace_attach() killable |
| |
On Thu, Nov 19, 2015 at 07:47:32PM +0100, Oleg Nesterov wrote: > ptrace_attach() can hang waiting for STOPPED -> TRACED transition if the > tracee gets frozen in between, change wait_on_bit() to use TASK_KILLABLE. > > This doesn't really solve the problem(s) and we probably need to fix the > freezer. In particular, note that this means that pm freezer will fail if > it races attach-to-stopped-task. > > And otoh perhaps we can just remove JOBCTL_TRAPPING_BIT altogether, it is > not clear if we really need to hide this transition from debugger, WNOHANG > after PTRACE_ATTACH can fail anyway if it races with SIGCONT. > > Reported-by: Andrey Ryabinin <aryabinin@virtuozzo.com> > Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Thanks.
-- tejun
| |