Messages in this thread | | | Date | Thu, 22 Sep 2022 10:48:59 -0400 | Subject | Re: [PATCH v2] tracing: Disable interrupt or preemption before acquiring arch_spinlock_t | From | Waiman Long <> |
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On 9/22/22 10:31, Peter Zijlstra wrote: > 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 :-)
Sorry for the omission. The patch should have the following fixes tags.
Fixes: a35873a0993b ("tracing: Add conditional snapshot") Fixes: 939c7a4f04fc ("tracing: Introduce saved_cmdlines_size file")
Cheers, Longman
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