Messages in this thread | | | Date | Tue, 27 Sep 2022 13:12:21 -0400 | From | Steven Rostedt <> | Subject | Re: [Resend PATCH v2] tracing: Disable interrupt or preemption before acquiring arch_spinlock_t |
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On Tue, 27 Sep 2022 11:28:13 -0400 Waiman Long <longman@redhat.com> wrote:
> On 9/22/22 10:56, Waiman Long wrote: > > It was found that some tracing functions in kernel/trace/trace.c acquire > > an arch_spinlock_t with preemption and irqs enabled. An example is the > > tracing_saved_cmdlines_size_read() function which intermittently causes > > a "BUG: using smp_processor_id() in preemptible" warning when the LTP > > read_all_proc test is run. > > > > That can be problematic in case preemption happens after acquiring the > > lock. Add the necessary preemption or interrupt disabling code in the > > appropriate places before acquiring an arch_spinlock_t. > > > > The convention here is to disable preemption for trace_cmdline_lock and > > interupt for max_lock. > > > > Fixes: a35873a0993b ("tracing: Add conditional snapshot") > > Fixes: 939c7a4f04fc ("tracing: Introduce saved_cmdlines_size file") > > Suggested-by: Steven Rostedt <rostedt@goodmis.org> > > Signed-off-by: Waiman Long <longman@redhat.com> > > --- > > kernel/trace/trace.c | 23 +++++++++++++++++++++++ > > 1 file changed, 23 insertions(+) > > Ping! > > Any comment on this patch?
You may have noticed (from today's emailing) I applied the patch ;-)
-- Steve
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