Messages in this thread | | | Date | Mon, 8 Dec 2014 10:08:51 -0500 | From | Steven Rostedt <> | Subject | Re: [GIT PULL] tracing/NMI/printk: Use seq_buf for safe printing from NMI context |
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On Mon, 8 Dec 2014 10:05:28 -0500 Steven Rostedt <rostedt@goodmis.org> wrote:
> This code solves the issue of performing stack dumps from NMI context. > The issue is that printk() is not safe from NMI context as if the NMI > were to trigger when a printk() was being performed, the NMI could > deadlock from the printk() internal locks. This has been seen in practice. >
One added bonus is that this code also makes the NMI dump stack work on PREEMPT_RT kernels. As printk() includes sleeping locks on PREEMPT_RT, printk() only writes to console if the console does not use any rt_mutex converted spin locks. Which a lot do.
-- Steve
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