Date: Mon, 16 Jun 2003 02:21:44 +0100 From: Ian Dowse <iedowse@maths.tcd.ie> To: "M. Warner Losh" <imp@bsdimp.com> Cc: freebsd-arch@freebsd.org Subject: Re: Message buffer and printf reentrancy patch Message-ID: <200306160221.aa52952@salmon.maths.tcd.ie> In-Reply-To: Your message of "Sun, 15 Jun 2003 12:28:52 MDT." <20030615.122852.26275397.imp@bsdimp.com>
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In message <20030615.122852.26275397.imp@bsdimp.com>, "M. Warner Losh" writes:
>In message: <200306151406.aa36218@salmon.maths.tcd.ie>
> Ian Dowse <iedowse@maths.tcd.ie> writes:
>: occur via tputchar() when using xconsole, and generally make the
>: use of printf() in the kernel a bit safer. Many of the ideas here
>: were suggested by Bruce Evans.
>
>Safe enough to be used for ddb? That is, can we get the ddb output in
>out dmesg buffers?
That's what I use it for anyway - I use a laptop that has no serial
ports but does retain its memory contents across a reboot, so having
panic messages and stack traces left in the message buffer helps a
lot. There are probably a few ways of doing it, but I just replaced
db_putchar()'s contents with the following:
printf("%c", c);
if (c == '\r' || c == '\n')
db_check_interrupt();
This probably needs to have a sysctl to control the behaviour, as
many people won't want the message buffer to be filled up with
interactive DDB output normally.
Ian
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