Messages in this thread | | | Date | Fri, 22 Apr 2022 23:13:50 +0200 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH v2 0/5] ptrace-vs-PREEMPT_RT and freezer rewrite |
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On 2022-04-22 14:15:35 [-0500], Eric W. Biederman wrote: > Sebastian Andrzej Siewior <bigeasy@linutronix.de> writes: > > > On 2022-04-21 17:02:48 [+0200], Peter Zijlstra wrote: > >> Find here a new posting of the ptrace and freezer patches :-) > >> > >> The majority of the changes are in patch 2, which with much feedback from Oleg > >> and Eric has changed lots. > >> > >> I'm hoping we're converging on something agreeable. > > > > I tested this under RT (had to remove the preempt-disable section in > > ptrace_stop()) with ssdd [0]. It forks a few tasks and then > > PTRACE_SINGLESTEPs them for a few iterations. > > Out of curiosity why did you need to remove the preempt_disable section > on PREEMPT_RT? It should have lasted for just a moment until schedule > was called.
within that section spinlock_t locks are acquired. These locks are sleeping locks on PREEMPT_RT and must not be acquired within a preempt-disable section. (A spinlock_t lock does not disable preemption on PREEMPT_RT.)
> Eric
Sebastian
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