Messages in this thread | | | Date | Thu, 24 Sep 2020 10:40:10 +0900 | From | Sergey Senozhatsky <> | Subject | Re: [RFC 2/2] printk: Add more information about the printk caller |
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On (20/09/23 15:56), Petr Mladek wrote: > The information about the printk caller has been added by the commit > 15ff2069cb7f967da ("printk: Add caller information to printk() output."). > The main motivation was to reconstruct original messages when they > longer output from different CPUs got mixed. > > But there are more usecases. The number of CPUs and tasks running on > a single system is growing. It brings bigger challenges when debugging > problems. The context in which kernel reports its state is sometimes > pretty useful. > > In particular, people suggest to remember the task id, cpu id, more details > about the interrupt context, and even the task name [0][1]. > > Prepare for extending the caller information by replacing caller_id > with struct printk_caller. And always store task id, cpu id, and > exact interrupt context.
Wild idea:
Currently, we have two sides to the problem, I think. There are tasks that store messages, but then there are tasks that print those messages on the consoles. And those tasks and contexts are not always the same. What I found helpful in the past was not only the caller_id, but the emitter_id (especially preemption count and irqs state of the context that prints messages on the slow consoles).
-ss
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