Messages in this thread | | | Date | Thu, 22 Sep 2022 16:31:46 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2] tracing: Disable interrupt or preemption before acquiring arch_spinlock_t |
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On Thu, Sep 22, 2022 at 09:31:58AM -0400, 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. > > Suggested-by: Steven Rostedt <rostedt@goodmis.org> > Signed-off-by: Waiman Long <longman@redhat.com>
This seems to be missing a Fixes: tag :-)
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