From: Lucas Tanure <tanure@linux.com>
To: aleave <aleave@protonmail.com>
Cc: "kernelnewbies@kernelnewbies.org" <kernelnewbies@kernelnewbies.org>
Subject: Re: How to printk synchronously
Date: Tue, 26 Nov 2019 22:31:08 +0000 [thread overview]
Message-ID: <CAJX_Q+0i7diV5j0G11bCDPf3SHLse0AxZktuvz4m0_iwbE=WoA@mail.gmail.com> (raw)
In-Reply-To: <kUQdnenuZBA_XCFa9mZuSwBHPQgMXwjo1mXzg2fPOKxVxwwZsjON4Faf4F_-jT6c81EIBCdSAytgATCFGxpkjTvhnpKgTjpqU9Z_rCtHNgc=@protonmail.com>
Hi,
What about ftrace ? Documentation/trace/ftrace.txt
Thanks
Lucas
On Tue, Nov 26, 2019 at 8:08 PM aleave <aleave@protonmail.com> wrote:
>
> Hi everyone,
>
> I'm modifying kernel code and running into system dead-lock issues. I have printk statements to try to retrieve info about the freeze after I do a hard shutdown, but printk is asynchronous so /var/log/kern.log only shows NULL character gibberish instead (^@^@^@^@). Is there a way to make printk synchronous? I have looked at people using printk_sync and printk.synchronous variables as recently as 2017, but I don't see any reference to these anymore in the kernel version I have (5.4).
>
> Thanks for the help.
>
>
> _______________________________________________
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> Kernelnewbies@kernelnewbies.org
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next prev parent reply other threads:[~2019-11-26 22:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-26 20:07 How to printk synchronously aleave
2019-11-26 22:31 ` Lucas Tanure [this message]
2019-11-27 9:18 ` Valdis Klētnieks
2019-11-28 6:12 ` Muni Sekhar
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