Date: Wed, 14 Jun 2017 23:12:32 -0600 From: Warner Losh <imp@bsdimp.com> To: Gleb Smirnoff <glebius@freebsd.org> Cc: Konstantin Belousov <kostikbel@gmail.com>, src-committers <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org> Subject: Re: svn commit: r319874 - head/sys/kern Message-ID: <CANCZdfr3zqSnjP3WhKngM6UNpYKkRkUcrsAJvSWbWKdeBV%2Br8A@mail.gmail.com> In-Reply-To: <20170615050400.GP50023@FreeBSD.org> References: <201706122111.v5CLBBUT092606@repo.freebsd.org> <20170612234356.GD50023@FreeBSD.org> <20170613120643.GX2088@kib.kiev.ua> <20170615050400.GP50023@FreeBSD.org>
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On Wed, Jun 14, 2017 at 11:04 PM, Gleb Smirnoff <glebius@freebsd.org> wrote: > On Tue, Jun 13, 2017 at 03:06:43PM +0300, Konstantin Belousov wrote: > K> On Mon, Jun 12, 2017 at 04:43:56PM -0700, Gleb Smirnoff wrote: > K> > On Mon, Jun 12, 2017 at 09:11:11PM +0000, Konstantin Belousov wrote: > K> > K> Author: kib > K> > K> Date: Mon Jun 12 21:11:11 2017 > K> > K> New Revision: 319874 > K> > K> URL: https://svnweb.freebsd.org/changeset/base/319874 > K> > K> > K> > K> Log: > K> > K> Print unimplemented syscall number to the ctty on SIGSYS, if > enabled > K> > K> by the knob kern.lognosys. > K> > > K> > Why is it off by default? > K> In some (non-default) situation it may cause lot of ctty output. > K> I made the knob tunable to allow it to be set very early (init) > K> if needed. > > I remember myself being a beginner UNIX user, and all this > "bad system call, core dumped" messages were so annoyingly > uninformative for me, and I had no idea how to track to the > actual problem. This feature gives a lot of clue for a beginner > user, but having it default to off, devaluates its value. > We can also rate limit the messages. We have the technology. Warner > > To avoid possible tty spam for an application that produces ton > of bad syscalls, but ignores SIGSYS, we can enable the feature > for those processes, who doesn't ignore SIGSYS. > > -- > Totus tuus, Glebius. > >
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