Messages in this thread | | | Date | Mon, 08 Nov 2021 23:43:31 +1000 | From | Nicholas Piggin <> | Subject | Re: [PATCH] printk: restore flushing of NMI buffers on remote CPUs after NMI backtraces |
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Excerpts from Petr Mladek's message of November 8, 2021 6:34 pm: > On Sun 2021-11-07 14:51:16, Nicholas Piggin wrote: >> printk from NMI context relies on irq work being raised on the local CPU >> to print to console. This can be a problem if the NMI was raised by a >> lockup detector to print lockup stack and regs, because the CPU may not >> enable irqs (because it is locked up). >> >> Introduce printk_trigger_flush() that can be called another CPU to try >> to get those messages to the console, call that where printk_safe_flush >> was previously called. >> >> Fixes: 93d102f094be ("printk: remove safe buffers") >> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > > Reviewed-by: Petr Mladek <pmladek@suse.com> > > We should add also > > Cc: stable@vger.kernel.org # 5.15 > > No need to resent the patch. I could add it when pushing. > > Plan: I am going to wait one or more days for a potential feedback > and ack from John. Then I am going to push this into printk/linux.git.
That sounds good to me.
> IMHO, it makes sense to get this into 5.16-rc1 or rc2.
Agree.
Thanks, Nick
> Thank you both a lot for nailing this down and for the fix. > > Best Regards, > Petr >
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